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Laser Engraving and Cutting
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  • How to “Paint” a Picture on Stainless Steel, Using the Snapmaker Ray 40W Laser Module (Part 2)

     

    Introduction to Laser “Painting” on Stainless Steel

    So you’ve spent the last few weeks running test array in order to define a set of parameters that will give you a nice set of colors on stainless steel and you’re thinking, “Now what? How do I actually use these colors to make a picture?” Fear not! Help is at hand! In this tutorial, I will explain my step-by-step process for creating an image like the one you see above using your Snapmaker Ray. I assume that the basic steps will port fairly smoothly over to the Snapmaker’s 3-in-1 tools (like the A350T) but I can’t make any promises since I haven’t tried to do it on both machines yet. If you are interested in pursuing projects in laser color marking and haven’t yet done so, I encourage you to start with my tutorial on that subject before diving into the depths of making images.

     

    Materials and Useful Accessories

    As I note in the other tutorial, my best results to date have come from using “frosted” steel plates of at least 1 mm thickness, sourced from Amazon. I usually use square pieces of 100 mm by 100 mm, with a protective film on both sides that keeps the surface of the steel from getting scratched prior to use. I usually peel the film off just before placing the metal sheet into my Ray, to minimize the chance of getting scratches or fingerprints on the surface. If you do get fingerprints, I recommend cleaning off the steel using a lint-free towel and 99% Isopropyl Alcohol. That leaves a nice, clean surface on which to “paint”. Again, I will be using my aluminum hold-down plate and button-head screws to secure the steel plate during “painting”.

     

     

    Laser Parameters Reference File

    If you came here after going through my tutorial on Laser Color Marking, you should already have a LightBurn reference file containing a colored test array of squares that sets out the proper laser power / speed / intervals / etc for the different colors you have available. I usually start every new image project by making a copy of the reference file and renaming it with the name of the new image. That helps prevent making changes to the original reference file and potentially losing your set of laser parameters. If you place your test array of colors outside the working area in LightBurn, it will happily just sit there and not be included in any G-code output files you create, but you can still use it to define all your laser color parameters.

    Outline of the Laser-color Image Creation Process

    Below I list the steps we will follow that will ultimately result in a G-code file that you can load into Luban and run on your Ray. After the outline, I’ll go through each of the steps individually and explain what they mean.

    Outline of picture process

    1. Select picture
    • Best is something with well-defined color areas, little shading, color set close to what is available or can be adjusted to fit what you have.
    1. Open picture in GIMP
    2. Select by color
      • CTRL + C to copy.
    3. Paste as new image
    4. Export as JPEG or PNG with label as that color (or color #1 …)
    5. Open LightBurn
    6. Open file where you have color parameters setup
      • Should have colors in test array outside of active area.
        • Won’t show up in output G-code.
    7. Import JPEG / PNG into LightBurn
    8. Trace Image (reduce min size to zero from default of 2)
      • Increase Threshold to get all but outer profile.
    9. Drag thing you just traced to side and delete
    10. Assign a color/raster parameters to that layer
    11. Go back to GIMP and delete that color from working image
    12. Repeat Steps 3-12 for each color in working image
      • Can combine layers to same color if you want to.
      • Drag each new layer to correct position relative to previous layers.
    13. Select entire image and resize to fit steel workpiece
      • I use 90 mm as max on 100 mm square to keep away from hold down screws / washers.
    14. Re-zero to put bottom corner at 0, 0
    15. Save complete image as new Lightburn Project
    16. Check simulation to get idea of time required for all layers
      • Can turn off output of layers to reduce time for a given laser session.
    17. When time looks right, save G-code

     

    Step 1 Select Your Picture

    Given the limited set of colors accessible with our lasers, not every image / picture is going to be suitable for use in the laser color marking process.

    Before jumping into this first step, I want to talk briefly about two basic ways to “make” a given color show up in an image: “dithered” and “non-dithered”. In a dithered image, color in a given area is created by combining smaller areas (sometimes single pixels) of multiple colors in your palette in an attempt to present a sort of average / mixed color. The simplest example of this is found in black and white newsprint, where a “grey” pixel is created by splitting a pixel into white sub-pixels and black sub-pixels. From a distance, the eye will visually “average” that pixel into something between black and white. The smaller your sub-pixels, the more different levels of “grey” you can obtain in that spot. The same thing works with colors, originally by combining red, green, and blue (RGB) sub-pixels, but now often adding additional colors to the mix. Looking at your phone or computer screen close-up with a magnifying glass will show you this in action. Using dithering works best when the colors of your sub-pixels are saturated and contrasty, which is typically not the case for many of the colors found with laser color marking on stainless steel. Also, much of the color effect we see on steel comes from the degree of overlap between adjacent laser lines or laser dots, so if we try to use too small of a sub-pixel in dithering, we will likely not get the expected color. For these reasons, I recommend NOT using dithering when trying to make colored images. If I figure out how to do this in the future, I’ll come back and edit this tutorial to reflect that. But for now, let’s just focus on non-dithered images.

    Keeping the above in mind, I generally look for images that have clear, well-defined areas of color, with very little shading. Below I show three example images: two that are well suited for this process, and one that isn’t.

     

     

    https://pixabay.com/vectors/abstract-colourful-dance-dancer-2029887/

    https://pixabay.com/vectors/octopus-animal-cartoon-nature-8576823/

     

    Image #1 would be an excellent choice for laser color imaging because its colors are well-defined and quite “contrasty”, and would look good with multiple color replacement sets (if you liked some of your colors better than the ones in the image). Image #2 was an acceptable choice (see the header image on this tutorial), even though it contains a larger number of colors than #1, even though some of its colors are not particularly close to the ones we have available. It depends on how close to the original color set you feel it is important to achieve. As is often the case, I made multiple versions of #2 until I found a color set I liked best.

     

    https://pixabay.com/illustrations/landscape-illustration-nature-water-4394746/

     

    Image #3 would probably be a poor choice for this process. Even though it has a limited color palette, there is a lot of subtle shading that would be very difficult to replicate. In the end, much depends on your level of patience and willingness to dive into the details of an image.

     

    Step 2 Open Your Picture in GIMP

    The next step in our process is to start breaking your picture down into its individual color components. There are many different image processing programs that could do many of the rest of these steps, but I chose GIMP for the simple reason is that it is free to use, and quite powerful. Using our Octopus as an example, this is what my screen looks like after I’ve opened the file in GIMP.

     

     

    Steps 3-4 Select by Color, Paste As New Image

    On the Menu bar, choose Select and then By Color (Shift + O). In this example, let’s start by selecting the background (purple) color by placing the cursor crosshairs on the background and clicking it. The outline of that color (everywhere it exists in the image) will be highlighted by a flashing dotted line. Now click on CTRL+C to copy that color into the clipboard. We then click on Edit on the Menu bar and choose Paste As > New Image (CTRL + SHIFT + V). This will create a new image page that only contains the selected color.

     

     

    Step 5 Export This Page

    We now go to File on the Menu bar, and select Export. This will open an Export window that will allow you to choose a name for this file and where to save it on your computer. Try to name it something helpful, like “Octopus background color.PNG”. The default file type will be PNG, which is fine. If you prefer JPEG, that should work, too. Our next step will be to import this file into LightBurn, so any image file type the Lightburn can read should work. I have created a folder on my Desktop specifically for Snapmaker Ray project files, so this is where I usually export mine to.

     

    Steps 6-8 Create a NEW Copy of Your LightBurn Color Test Array File, and Import the (Single Color) Image File You Just Made

    Below is what my computer screen looks like at this point:

     

     

    You can see my color test array on the left (outside the work area), a big copy of the background color image file in black and white in the middle of the screen, and my laser parameters Cuts / Layers window on the right side. Select the image with your cursor (you may need to click the Arrow icon on the left side of the screen).

     

    Step 9 Trace the Image

    With the image selected, right click the cursor (or use the Tools dropdown on the menu bar) and choose Trace Image. Your screen should now look like the picture below. There should be a purple outline of the image. I advise that you change the Ignore less than value to zero (0) and push the Threshold slider up to near the upper end of its range to capture as much detail as possible. Note that if you push the Threshold slider up all the way to its max value, the purple outline will disappear. Make sure not to go that far! Reducing the Ignore less than value will make sure the trace doesn’t ignore small spots of color. Sometimes it is also necessary to play around with the Cutoff slider to make sure you capture everything. When the single color files are exported from GIMP, their “blackness” level will reflect their color “value”, so a lighter color will be exported as more of a grey image than the one we see below. The Trace Image function is looking for where the contrast in the image changes, so adjusting the Cutoff value can compensate for a lower contrast. The idea is just to make sure you “get” all of the colored area enclosed by the trace.

     

     

    Step 10-11 Assign Traced Image a Set of Color Parameters and Delete Original Image

    Although the screen won’t look any different at this point, what you have done is to create an new layer underneath the original, typically now assigned to the most recent set of color parameters used. You can see this by dragging the top layer away to the side. Underneath you will find a layer that looks the same, but has now been converted into an area which can be “filled” by a color. If it’s the first time you’ve done this step, it will be assigned to the “00” layer and will still be black (look at the list of colors on the bottom of the window).

     

     

    If you now click on this new layer, you can then click on one of the other colors at the bottom of the window and it will be assigned to that “cut/layer”. In the picture below, I’ve assigned it to Cut / Layer 09 causing it to now look dark blue.

     

     

    Once you have accomplished this, it is okay to delete the original image copy on the right side.

     

     

    If you were now to click on the Save GCode button under the Cuts / Layers window on the right, LightBurn would write a set of G-code commands to a file that would “Cut” that image out using the laser parameters set up for Cut / Layer 09. Namely, a laser travel speed of 2500mm/min, a Line Interval Spacing of 0.05mm, and a power of 12.7%, which are the values I previously found to give a nice dark blue. If you decided after this point that you wanted the background to be a different color than Dark Blue, all you would need to do would be to click on the layer and then click on a different color square on the bottom of the window. Note that if you inadvertently assign it to a color that you haven’t defined with your test array, it will choose a default set of parameters from the top of the Cuts / Layers window (White in my case), so if one of your images ends up with an area that is unexpectedly a different color than you were expecting, this may be the cause.

     

    Step 12 Return to GIMP and Delete That Color from the Working Image

    In this step we return to GIMP and delete the color we have just added to our Lightburn project. This will help us keep track of the colors we have completed and which ones we still have yet to process. The picture below shows what your computer screen should show after you delete that color.

     

     

    Step 13 Repeat Steps 3-12 Until You Run Through All the Different Color Areas

    From this point on, we are just going to repeat Steps 3-12 for every different color in the starting image. If there are areas in the original image that have different colors that you wish to combine into a single color, simply hold down the SHIFT key while clicking with the mouse on the additional color areas. Alternately, this step can be done in LightBurn by clicking on a given layer and then assigning it to one of the colors already used. This will make both areas part of the same Cut / Layer.

    Each time you add a new color layer to the LightBurn Project you should move it to line up with the first layer. You can also do small shifts by adjusting the numerical values in the X and Y boxes when the layer you wish to move is selected. For very small layer movements, it is helpful to zoom into the image.

     

    Steps 14-15 Rescale the Layers and Zero the Corner

    Once all the color layers are complete and aligned with one another, we use the select rectangle to select all the layers and then enter the appropriate dimension in the Height or Width boxes. If you are using a 100 mm square piece of steel, I recommend a maximum dimension of 90 mm to keep the edges of the image away from the hold-down screws.

     

     

    You should also place the corner of the image at the 0,0 position (I always use the bottom left corner as the default zero point, as one of the arrows shows).

     

    Step 16 Save the Completed Project As a LightBurn Project

    Make sure to save the project at this point, in case you want to come back later and make modifications to layer positions, colors, etc.

     

    Step 17 Check Your Laser Time Prediction

    By clicking on the Preview icon at the top of the LightBurn window (see arrow below) you can get a good estimate of how long the laser time is predicted to be once you press the START button on your Ray. I have found LightBurn’s estimates to be quite accurate if you have followed the instructions for setting up LightBurn to work with the Ray.

     

     

    If you find that the laser time is longer than you wish to babysit the Ray, you can “turn off” layers by switching the Output to OFF in the Cuts / Layers window (see arrow). You can choose to laser anything from a single layer to all the color layers, depending on how much time it will take vs how much time you want to spend babysitting the laser.

     

     

    Step 18 Save the G-code to Your Computer and Load into Luban

    Whatever layers have their Output ON in the LightBurn Cuts / Layers window will be included in the set of G-code instructions that are generated when you click on the Save GCode button.

     

     

    Once you have saved the G-code to your computer, you can start Luban and load the G-code into the Workspace window.

     

     

    I will note here that in my attempts to set up LightBurn to work with my Snapmaker, I have somehow ended up with an X offset in the Luban G-code image of 21 mm (negative), which you can see in the above picture. However, the origin of the image generated by the diode laser still uses the red laser crosshair point as its effective origin. So I just ignore the offset in the image on the screen.

    Once you have imported the G-code file into Luban, you can upload it to your Ray, position your laser on your workpiece, and press the Start button. If you have opted not to include all of the color layers in the current laser file, make sure NOT to manually move the laser from the origin position in between laser sessions, unless you have established some way to return it to precisely the same position before you burn the rest of the layers. Otherwise, the origins of the different G-code session will likely be in different spots and your colors won’t line up between the sessions.

    Below is the final output from my pre-defined color set, following the steps I have laid out above. Total laser time was 3 hours and 50 minutes.

     

     

    Image References

    https://pixabay.com/vectors/abstract-colourful-dance-dancer-2029887/

    https://pixabay.com/vectors/octopus-animal-cartoon-nature-8576823/



  • Color Laser Marking on Stainless Steel, Using the Snapmaker Ray 40W Laser Module (Part 1)

     

    Introduction to Light Interference Color

    If you are interested in pursuing projects in laser color marking, I encourage you to start with at least a few of the existing YouTube videos about color via light interference. There are many ways to treat steel to obtain colors, but they all take advantage of the same underlying principle: a transparent chromium oxide layer on the surface of the steel creates an interference effect when light reflects from the top and bottom surface of the oxide layer. In our case, we are using the laser to heat or melt the surface of the steel plate in order to change the thickness of that chromium oxide layer. The heated steel reacts with the oxygen in the air and forms an essentially transparent metal oxide (like glass). The color we see is due to light bouncing off both the top oxide surface and bottom metal/oxide interface. These two reflections add constructively or destructively to result in one wavelength of light being enhanced in reflection. As the oxide thickness increases, the enhanced wavelength also increases, resulting in colors that start out blue/violet, and shift towards red. This is the same thing that happens with the colors you may have seen next to steel welds or tempered steel. It is also possible to accomplish the same oxide growth using an electrolyte bath and a voltage / current source. Many of the existing videos are presented from the perspective of Fiber laser owners, which have some additional control “knobs” to what we have on diode lasers, but the general concepts are broadly applicable to any laser system with the capability of heating / melting the surface of stainless steel. That’s how I started these investigations, and it was a great way to get a quick intro to the field. A good example is linked below:

    Light interference Colors on Stainless Steel MOPA Fiber Laser Color

    Watching the videos above will give you a good idea of the science underlying laser color marking (thin film optical interference) and reasonable expectations about what kinds of colors can be obtained. That’s pretty much the starting point I had when I began my own experiments.

     

    Materials and Useful Accessories

    A quick note about stainless steel. There are a vast number of different kinds of steel with differing chemical compositions, and the opinions about what the best steel to use for laser color marking seem to pretty much zero in on 304 Stainless (with 201 Stainless being the 2(nd) choice). I have yet to find an explanation of why 304 Stainless seems to work best, so I can’t comment on the truth of this opinion. I’ll come back and edit this later if I find out. Since I’m not trying to get another PhD, I decided to start with 304 stainless and not worry about it for the time being.

     

    My best results to date have come from using “frosted” steel plates of at least 1mm thickness, sourced from Amazon. The heat generated by the laser for some of the colors is easily enough to warp the steel due to local heating, so plates thinner than 1mm were harder for me to work with. Ultimately, I purchased an aluminum hold-down plate with many tapped holes and then used Flanged Button Head screws to hold down the edges of the steel plates during laser marking. Otherwise, the plates could bend so much that they could defocus the laser. I used wide washers and more screws to hold down the middles and corners of the steel plate on the “free” sides shown in this picture. The washers provide hold-down points for pieces whose sizes aren’t an exact multiple of the tapped hole spacing.

     

     

    Setting the Laser Parameters

    My next step was to take a screenshot out of one of the videos that Snapmaker released to show the capabilities of the new RAY system where they BRIEFLY showed a test array for laser color marking one of their engineers had done. That gave me a place to start for laser power, line interval spacing, and laser work speed. From there I began a multi-week dive into the various parameters used to produce different laser colors. Indispensable to that effort was the LightBurn program (https://lightburnsoftware.com/), where I was able to make excellent use of their 30 day free trial period. LightBurn has a built-in option to create test arrays where you can vary the different laser parameters in a consistent way. One example is shown below:

     

    In an array like the one above you can see how different settings, such as Line Interval Spacing and Travel Speed, impact the resulting color. You can also leave one of these parameters fixed, and instead vary Laser Power. As a word to the wise, when you start getting close to colors that you like, make sure to try arrays of larger area than the small squares above. Even if a small square looks uniform, a large square at those same setting will often show visual defects that weren’t obvious in a smaller area. I learned (and re-learned!) that lesson many times!

     

    Filling an Area with Color (Rastered Lines vs. Dot Filling)

    One thing to keep in mind here is that, while the color is primarily dependent on the thickness of the metal oxide you create, there are multiple ways to influence that thickness. Some changes have large effects, while others can be more subtle. Depending on what effect you may be trying to achieve, different ways the laser power is delivered to the steel surface can result in two areas that get the same “integrated” power looking different from each other. Maybe the most obvious example of this comes from (I assume) the “roughness” of the buried metal surface. Here I’m referring to the interface between the transparent metal oxide and the steel. A very smooth metal surface acts much like a mirror (what is referred to as “specular” reflection). Light bouncing off a mirror-like surface reflects off at the same angle as the incoming light. A rough surface, on the other hand, produces what is called a “diffuse” reflection, bouncing light off much more uniformly, over a wider range of angles. In the case of laser color marking, these effects have a strong impact on what colors we see, especially as we look from different angles. If a surface is highly reflective, we may see very different colors in any given area as we change the angle from which we are looking. If a surface is more diffuse, the color will be much more uniform over multiple angles. The “frosted” steel plate surface is an excellent example of this effect. I found that difference in angular color appearance to be particularly pronounced when comparing color markings done using the standard “rastered lines” for filling areas as opposed to Luban’s option for “dot filling”. I suspect this is primarily from the difference in the roughness of the buried metal surface between these two methods of filling space. Whatever the cause, I found the colors obtained from “dot filling” to be much more consistent when viewed from different angles. As always, I encourage you to try out both “dot filling” and “rastered line filling” to see which style appeals to you more. The dot filling approach is generally slower (you are stopping and starting the laser motion MANY more times than with rastering), but it does look better (in my opinion). One significant downside to dot-filling is that it is not available as an option to fill an area in LightBurn. Below I show some images of two butterflies with similar colors (at least in some viewing directions) made using line-rastering (on the right) and dot filling (on the left). As you can see, the colors of the dot-filled areas are much more consistent when viewed from different angles, while the line-filled areas look dramatically different from some angles where the “specular” effect is quite strong. For the butterfly images, I found the dot-filled color areas to look much better from multiple angles, although a more specular area can really “pop” at the right angle.

     

     

    Two additional settings/parameters I will discuss are Overscanning and Constant Power Mode / Adaptive Power Mode. They are somewhat interrelated, so I will talk about them together. Overscanning is a parameter in LightBurn that is typically represented as a percentage (%) of your travel speed. This percentage refers only to the speed of laser travel and will extend the length of the laser travel beyond the boundaries of your fill area. For any given Overscanning percentage, a higher speed will result in a larger amount of extra travel. The purpose here is to give the laser time to start moving and get up to the target speed before getting to the area where the laser is to turn on, and then to wait to start slowing down until after the laser has been turned off. A larger travel speed setting will need more space/time for the laser to get up to speed, so making the Overscanning distance a percentage dependent on speed makes sense. Since the laser power is a critical determinant of the oxide thickness, any variations as you move across the fill area will result in color shifts, especially near the edges of the area. If you leave “Constant Power Mode” off, the Snapmaker firmware will attempt to compensate for variations in travel speed by adjusting the laser power. Thus, if the laser is traveling more slowly than the target speed, the firmware will reduce the laser power in an attempt to provide the same integrated power to a given area. Unfortunately, the accuracy of this compensation method isn’t always where it needs to be for laser color marking. I typically found my best color results with “Constant Power Mode” switched ON in LightBurn and the Overscanning parameter set between 10% and 50%. Of the two parameters, Overscanning is much more important than the power mode. If you set the Overscanning parameter high enough, you shouldn’t need to invoke Constant Power Mode at all. I will note here that Luban also includes an Overscanning parameter, but in my limited attempts I could not make it work. If you are sticking entirely with Luban, using Constant Power Mode will be critical, as it is the only way you will have to compensate for speed variations.

     

    LightBurn’s Cut Settings Editor Window

    Below, I show an image of the LightBurn Cut Settings Editor popup window, where I set the line rastering parameters for the color I have chosen to call “Blue”. We can see that I have chosen a Line Speed of 2500mm/min, a Power of 13.5%, and a Line Interval spacing of 0.05mm. The Constant Power Mode is turned OFF, and the Overscanning is ON and set to 10%. This overscan results in an “extra” 4.17mm being added to each end of the line to allow the laser to get to the target speed before it turns on, and then to slow down after it turns off. The higher the percentage you set, the more extra travel and thus the better chance of hitting the right speed before the laser turns on. On the other hand, this also increases the length of time needed for each line, and thus your entire color marking project. Since the extra distance is only a function of your speed and not the size of the object you’re filling, the time “multiplier” will be worse for smaller areas than for larger ones. In other words, if the object you are filling is only 4mm wide, this 10% Overscanning (at a speed of 2500mm/min) will roughly triple the time needed to fill it, since it adds ~4mm onto both ends of each line. If your fill object is instead 40mm wide, an extra 4mm travel on each side increases the time needed by only 20%. Just find a value that works for you.

     

     

    For the sake of convenience, I have tried to find a set of parameters that would give me colors similar to the presets in LightBurn (on the left of the above image), so that any images I created there could look at least something like what I could expect to produce from my laser setup. In the end, I got close with some, less close with others, and way off with a few. Good red and green colors still elude my attempts, for example, while you can have pretty much any kind of blue you want. What follows are my best efforts thus far, for both line-filled and dot-filled colors. They seem to give somewhat different colors each time I switch to a new batch of steel plates, so there is always some fine tuning to be done if I’m trying to hit a specific color. Anything that affects the amount of laser power absorbed at the surface of the metal will change the amount of oxide you get, so differences in surface chemistry and surface roughness will both come into play here. Another factor I haven’t mentioned here is the thermal conductivity of the metal. How much oxide you get will also depend on how quickly heat dissipates from the laser spot. Thus, metals with high thermal conductivity (like copper and aluminum) don’t work for laser color marking. Titanium, on the other hand, has a very low thermal conductivity and absorbs light well at the wavelength of our blue diode lasers, and thus works well for color marking. If I can find some stainless steel with a significantly different thermal conductivity than 301, I’ll test it out to see how this affects the color marking.

     

    Example Laser Parameter Sets

    Below I show examples of my current “best” set of parameters for both rastered line color and dot filled color. I attempted to create the same set of colors using both techniques, so the missing squares in the dot-filled color example mean that I wasn’t able to find a good set of parameters for those colors.

     

    Rastered Line Color

    White

    2500 mm/min

    19.8% Power

    20% Ovscn

    0.074 mm LI

    CPM

    Light Grey

    1000 mm/min

    18.6% Power

    20% Ovscn

    0.040 mm LI

    CPM

    Dark Grey

    1000 mm/min

    21.5% Power

    20% Ovscn

    0.040 mm LI

    CPM

    Black

    2500 mm/min

    65% Power

    20% Ovscn

    0.040 mm LI

    Air Assist

    Light Brown

    20500 mm/min

    74% Power

    20% Ovscn

    0.020 mm LI

    CPM

    Dark Brown

    2500 mm/min

    30% Power

    20% Ovscn

    0.030 mm LI

    Air Assist/CPM

    Blue1

    2500 mm/min

    16% Power

    20% Ovscn

    0.05 mm LI

    Blue2

    2500 mm/min

    15% Power

    20% Ovscn

    0.050 mm LI

    CPM

    Blue3

    2500 mm/min

    14% Power

    20% Ovscn

    0.05 mm LI

    CPM

    Blue4

    2500 mm/min

    13.5% Power

    20% Ovscn

    0.050 mm LI

    Royal Blue

    2500 mm/min

    12.7% Power

    20% Ovscn

    0.050 mm LI

    CPM

    Royal Purple

    2500 mm/min

    12.05% Power

    20% Ovscn

    0.050 mm LI

    Light Gold

    1500 mm/min

    17% Power

    20% Ovscn

    0.100 mm LI

    Dark Gold

    1000 mm/min

    15.6% Power

    20% Ovscn

    0.110 mm LI

    CPM

    Yellow/Orange

    2500 mm/min

    19.5% Power

    20% Ovscn

    0.048 mm LI

    Pink

    1000 mm/min

    18% Power

    20% Ovscn

    0.040 mm LI

    Wine

    1000 mm/min

    17.2% Power

    20% Ovscn

    0.120 mm LI

    Red

    1000 mm/min

    17% Power

    20% Ovscn

    0.110 mm LI

    Light Lilac

    2500 mm/min

    19.7% Power

    20% Ovscn

    0.040 mm LI

    Dark Lilac

    1000 mm/min

    17% Power

    20% Ovscn

    0.090 mm LI

    Light Green

    20500 mm/min

    38% Power

    10% Ovscn

    0.024 mm LI

    CPM

    Green

    1000 mm/min

    17% Power

    10% Ovscn

    0.055 mm LI

    Dark Green

    1000 mm/min

    18.6% Power

    10% Ovscn

    0.095 mm LI

     

     

    Dot Filled Color

     

    Light Grey

    0.05 mm FI

    45% Power

    5 msec/dot

    HDM

    AirAssist

    Dark Grey

    0.05 mm FI

    49% Power

    5 msec/dot

    HDM

    AirAssist

    Black

    0.05 mm FI

    55% Power

    5 msec/dot

    HDM

    AirAssist

    Light Brown

    0.05 mm FI

    18% Power

    5 msec/dot

    HDM

    AirAssist

    Dark Brown

    0.05 mm FI

    19% Power

    5.5 msec/dot

    HDM

    AirAssist

    Blue1

    0.05 mm FI

    26% Power

    5 msec/dot

    HDM

    AirAssist

    Blue2

    0.05 mm FI

    24% Power

    5 msec/dot

    HDM

    AirAssist

    Blue3

    0.05 mm FI

    22% Power

    5 msec/dot

    HDM

    AirAssist

    Blue4

    0.05 mm FI

    21.5% Power

    5 msec/dot

    HDM

    AirAssist

    Royal Blue

    0.05 mm FI

    19.75% Power

    5 msec/dot

    HDM

    AirAssist

    Royal Purple

    0.05 mm FI

    19.5% Power

    5 msec/dot

    HDM

    AirAssist

    Light Gold

    0.05 mm FI

    20% Power

    2.5 msec/dot

    HDM

    AirAssist

    Dark Gold

    0.05 mm FI

    31% Power

    5 msec/dot

    HDM

    AirAssist

    Yellow/Orange

    0.05 mm FI

    31% Power

    5 msec/dot

    HDM

    AirAssist

    Pink

    0.05 mm FI

    36% Power

    5 msec/dot

    HDM

    AirAssist

     

    Red

    0.05 mm FI

    32.25% Power

    5.5 msec/dot

    HDM

    AirAssist

    Light Lilac

    0.05 mm FI

    30.75% Power

    6 msec/dot

    HDM

    AirAssist

    Dark Lilac

    0.05 mm FI

    32.25% Power

    5 msec/dot

    HDM

    AirAssist

    Light Green

    0.05 mm FI

    34% Power

    5 msec/dot

    HDM

    AirAssist

    Green

    0.045 mm FI

    32.25% Power

    5 msec/dot

    HDM

    AirAssist

       

     



  • Laser on Ceramics: How to Make It Not Only Black on White

    ___.png

     

    Safety

    Laser

    You have only one pair of eyes and you need them! Always wear appropriate safety goggles while working with a laser! Fumes and gasses produced during lasering might be toxic. Use an enclosure with a fan and a hose connected to an exhaust (chimney or window).

     

    ___.png

    Chemicals

    Take time to read corresponding Material Safety Data Sheets (MSDS) before working with chemicals referenced in this article. Although most of them are relatively low dangerous, wear gloves, safety goggles and a respirator mask while handling powders. Keep in mind that isopropanol is a flammable solvent.

     

    Materials

    Ceramic Tiles

    These are widely available in construction stores, sometimes referred to as porcelain tiles. The glazed surface should be clean and free of grease, use isopropanol to clean it before using.

     

    ___1.png

     

    Titanium Dioxide

    Available in pottery stores. Despite its white color, it is responsible for black color after lasering. This is mostly due to formation of crystalline defects on the surface of TiO2 particles, as a result of partial reduction of titanium ions at high temperature, especially in presence of carbon and organic substances. These structural irregularities do not reflect the visible light, making such surface-modified titanium dioxide look black.

    The well-known and extensively documented Norton White Tile (NWT) method is based on this property of TiO2, as a main component of some common white paints sold in spray cans. This method is limited to black marking on white ceramics and is not covered in the present article.

     

    Ultrox - Zircopax Plus (Zirconium Silicate)

    Available in pottery stores. A white pigment widely used in pottery, it doesn't change its color at high temperature.

     

    Chalk (Calcium Carbonate)

    Available in pottery stores and elsewhere. I found it useful to add it to Zirconium Silicate in order to reduce the size of the white dot in the absence of organic binder. Most likely promotes faster cooling of the melted dot due to endothermic decomposition with release of carbon dioxide gas.

     

    Frit 3124

    Available in pottery stores, used mostly in glazes. A fine powder of glass composed of different oxides and having a low melting point, very useful to obtain color marking on ceramics.

     

    ___2.png

     

    Kaolin EPK

    Available in pottery stores, general purpose aluminosilicate white clay powder.

     

    Bentonite Western 325M

    Available in pottery stores, extremely fine Sodium aluminosilicate clay powder with a high capacity to swell in water. In absence of organic binder, it plays a role of viscosity-increasing (thickening) agent to slow down the sedimentation of the slurry and to facilitate its even spreading over the surface of the ceramic tile.

     

    Pottery Pigments

    Available in pottery stores. These are key components for color marking of ceramic tiles, fine powders of specially formulated mixtures of inorganic oxides encapsulated in zirconia glass. Some of these oxides are highly toxic, but in such an encapsulated state they are less dangerous. Yet, please use them with due care, protect yourself!
    I tried pigments produced by Mason and BASF. For more pure and vivid colors, avoid using organic binders: they produce carbon black while burning under the laser beam, which makes the color darker (unless this is your desired effect).

     

    ___3.png

     

    Polyvinyl Pyrrolidone (PVP) K-90

    Available in stores of materials for home-made cosmetics. A water-soluble binder and thickening agent. Helps to decrease the dot size. Can be used as a 2% solution in isopropanol (attention: full solubilization may take up to 72 hours with occasional agitation).
    Most likely, PVP could be replaced by Polyvinyl Alcohol, but I had no chance to test it.

    Unfortunately, the carbon black formed during laser burning of PVP and other organic binders makes them incompatible with white marking of black ceramic tiles. Also, colors get darker if such binder is used, for example, red becomes brown.

     

    Isopropyl Alcohol (Isopropanol)

    Available in general hardware and construction stores as a paint or lacquer thinner. Flammable, but not very toxic solvent miscible with water. Yet, take all safety measures!

    Avoid using isopropanol with high content of water from a pharmacy, if no other option, accordingly remove water addition from the slurry recipes below.

     

    ___4.png

     

    Process

    In this article, I will limit myself to a description of processing raster pictures. Vector images are easier to process, if necessary, laser parameters can be adjusted to get best results.

    The process consists in addition of material by melting it on the surface of the ceramic tile. This is not engraving, the glaze of the tile is not getting removed, but it slightly melts on the surface together with added material. The intensity of the laser beam does not affect the darkness of the resulting dot in a wide range of laser power. This means that a grayscale image cannot be rendered directly, through variation of the laser power, but only through picture pre-treatment while converting it to a black and white dotted image, a process called dithering.

     

    Picture Pre-Treatment

    Not all pictures would give suitable dithered images even if best algorithms are employed. This topic could be a subject of a whole separate article, I will only provide some general recommendations here.

     

    Picture Quality

    Your selected picture should have enough resolution, contrast and sharpness, the background should be blurry enough. The minimal resolution should be 10 dots/mm (254 DPI). Graphic pictures (sketches, drawings, engravings, pictures with enhanced contours) will be rendered better than soft halftone photos.

    For soft halftone photos with smooth transitions, I would recommend the use of special software or plugins to transform it into an artistic sketch or drawing, often this gives very interesting final results.

     

    ___5.png

     

    External Photo Editor

    In an external photo editor, you can not only adjust brightness and contrast of a picture with more precision and accuracy before dithering, but also improve sharpness, perform crop, adjust resolution, convert to grayscale, add vignetting and even proceed with dithering. This would give you full control of the process before importing the picture into Snapmaker Luban, even the possibility to delete or add individual dots after dithering.

    Please note that it is normal if the photo before final levels adjustment looks oversharpened.

     

    ___6.png

     

    Also, the external photo editor would be useful to separate colors for multi-color applications.

    For white on black process, the picture colors should be inverted before the final levels adjustment and dithering.
    For pictures with smooth tone transitions, it would be appropriate to use some artistic filters like G'Mic Illustration Look available in GIMP or Krita software and maybe some minor manual dodge/burn adjustments.

     

    ___7.png

     

    For final curve adjustment (using, only for example, Adobe Photoshop Levels tool), I would recommend the following generic parameters (provided the picture looks well-balanced on the screen): 

    • Black slider of Output levels: 130 to 200 (to prevent dots overlapping)
    • Midtone Slider: 1.50 to 2.00, depending on the picture

     

    ___8.png

     

    After this adjustment the picture should look considerably underexposed, but this is required in order to get normal rendering as a result of the whole process. Similar Levels tools are available in other photo editors as well. This is the simplest, yet efficient way to prepare your photos for lasering.

    I prefer a slightly more complex approach, using frequency separation and adjusting the levels only in the low-frequency background layer. This way the sharp contours are better preserved, yet no dot overlapping occurs in dark areas. Advanced photo editing skills are required in this case. 

     

    ___9.png

     

    If you prefer to perform dithering in an external editor, your picture resolution before that should match the expected laser Fill Interval processing parameter in Snapmaker Luban (for example, a resolution of 10 dots/mm or 254 DPI is equivalent to 0.1 mm fill interval). For dithering, I would recommend Stucki or Floyd–Steinberg algorithms. Note that Adobe Photoshop has a similar method in its conversion to Bitmap tool, under Image Mode menu line, it is called Diffusion Dither.

     

    ___10.png

     

    The dithered picture below is obtained in a different external editor (Photoline), which I prefer, using Stucki algorithm. Do not forget to save the dithered picture in bitmap (.bmp) format, otherwise the quality may suffer during import in Snapmaker Luban.

     

    ___11.png

     

    You can also use other laser-engraving softwares to control the whole process, but their descriptions are not the topic of the present article, in any case the basic principles stay the same.

     

    Importing into Snapmaker Luban

    Once imported into Snapmaker Luban, previously adjusted grayscale pictures may require scaling to match the predefined working area. Then proceed with dithering, better using Stucki or Floyd–Steinberg algorithms. Do not forget to switch to the GREYSCALE processing mode. If the picture was not adjusted well enough in an external photo editor, some limited tweaking can be performed using Contrast and Brightness sliders (the picture should look considerably underexposed on the preview), but I would recommend adjusting levels elsewhere before importing. It is better to use Snapmaker Luban sliders only for fine tuning.

     

    ___12.png

     

    If your picture has been dithered in an external photo editor (recommended), switch to B&W processing mode after importing the bitmap file and scaling. Please note that your picture resolution should match the expected laser Fill Interval processing parameter in Snapmaker Luban (for example, a resolution of 10 dots/mm or 254 DPI is equivalent to 0.1 mm fill interval), otherwise you will get unexpected results. The Threshold slider in this case affects only the preview of the dots on the screen, not the final result (except its extreme values of 0 and 255), so do not rely on the preview, it could be misleading.

     

    ___13.png

     

    Slurry Recipes

    General considerations: the powders should be carefully mixed in a dry beaker before adding liquids, and even more carefully mixed after. Protect yourself, apply safety measures!
    The proposed recipes are just examples, yet a few months of experimentation stand behind. You are free to unleash your creativity!

     

    Black

    This one has many similarities with classical Norton White Tile (NWT) process, with the following particularities:

    • Full control over the final result
    • Considerably cheaper
    • No highly toxic and highly flammable solvents involved
    • Deeper black color, higher contrast
    • Slightly larger dot (254 DPI recommended)
    • Better for drawings
    • A bit less good for soft grayscale pictures with smooth transitions

    In a dry polyethylene beaker, carefully mix the following components (by dry volume):

    • Bentonite Western: 1 volume
    • Kaolin EPK: 1 volume
    • Titanium Dioxide: 1 volume

    Add the following liquids, carefully mixing after each addition:

    • Isopropanol: 2 volumes
    • Water: 1 volume
    • 2% PVP in isopropanol: until ready for application

    The readiness for application is based on experience and desired effect: the thicker the final slurry, the thicker the layer on the tile. For better results, the layer should be thin enough, this would give smaller dots. A too thick layer may not work at all. Observe the way the slurry flows out of a bamboo stick: several drops a second should be OK.

     

     

    White

    In a dry polyethylene beaker, carefully mix the following components (by dry volume):

    • Bentonite Western: 2 volumes
    • Frit 3124: 1 volume
    • Chalk: 1 volume
    • Ultrox: 2 volumes

    Add the following liquids, carefully mixing after each addition:

    • Isopropanol: 2 volumes
    • Water: 2 volumes
    • Isopropanol: until ready for application

    PVP as a binder and thickening agent is not suitable in this case, due to undesirable carbon black formation at high temperature.

    The readiness for application is based on experience and desired effect: the thicker the final slurry, the thicker the layer on the tile. For better results, the layer should be thin enough, this would give smaller dots. A too thick layer may not work at all. Observe the way the slurry flows out of a bamboo stick: several drops a second should be OK.

     

     

    Color

    In a dry polyethylene beaker, carefully mix the following components (by dry volume):

    • Bentonite Western: 1 volume
    • Frit 3124: 1 volume
    • Pigment of desired color: 1 volume

    Add the following liquids, carefully mixing after each addition:

    • Isopropanol: 2 volumes
    • Water: 1 volume
    • Isopropanol: until ready for application

    PVP acts as a binder and thickening agent. It is not suitable if you want to get vivid colors, due to undesirable carbon black formation at high temperature.

    Otherwise, for darker colors but smaller dots, 2% PVP in isopropanol can be used in final addition.

    The readiness for application is based on experience and desired effect: the thicker the final slurry, the thicker the layer on the tile. For better results, the layer should be thin enough, this would give smaller dots. A too thick layer may not work at all. Observe the way the slurry flows out of a bamboo stick: several drops a second should be OK.

     

    ___14.png

     

    Ceramic Tile Pre-Treatment

    Always clean the glazed surface of a ceramic tile with isopropanol before covering with slurry, lens cleaning wipes are well suited for that.

     

    ___15.png

     

    Always mix well the slurry immediately before application: it has a tendency for sedimentation, especially if it does not contain PVP.

    To remove particulate matter, always filter the slurry through an old nylon stocking or sock before application.

    Cover the tile by an uniform layer of the slurry with a gentle pouring on its surface, followed by tilting in all directions to spread it evenly (isopropanol is flammable, keep away from sources of ignition!). Although it sounds simple, this operation is tricky and requires considerable training to get the desired uniformity of the layer. At the last step, a lazy-susan can help as a centrifuge.

     

     

    Also, the slurry can be sprayed on the surface using a pneumatic paint spray system. This would require a preliminary dilution of the slurry with more isopropanol (beware of sedimentation!). Personally, I prefer the pouring approach, since it creates less mess.

    Once the tile is covered, let it dry for at least 2 hours at room temperature (isopropanol is flammable, keep away from sources of ignition!) . After that, it is ready for laser treatment.

     

    ___16.png

     

    Toolpath Parameters in Snapmaker Luban

    With a 10W Snapmaker Laser module, the following parameters are applicable for this process:

    • Movement mode: Line
    • Fill interval: 
      • 0.1 mm for slurries with PVP as a binder (black or dark color)
      • 0.2 mm for slurries without PVP (white or vivid color)
    • Work Speed: 3000 mm/min
    • Jog Speed: 5000 mm/min
    • Laser Power: 70%

    Please note that if you preformed dithering before importing into Luban, your picture resolution should match the laser Fill Interval processing parameter in Snapmaker Luban (for example, a resolution of 10 dots/mm or 254 DPI is equivalent to 0.1 mm fill interval), otherwise you will get unexpected results.

     

    ___17.png

     

    Be careful with Fill Interval parameter, decreasing it below recommended values can lead to overlapping of dots, resulting in local overheating and melting of tile glaze. This may have a negative effect on the image quality, as these overlapped spots would look like less exposed ones (less deep blacks, or less bright white, or less saturated color, depending on the slurry recipe used). This may happen also as a result of improper preliminary photo processing.

    The dot size is not only related to the focusing of the laser beam, there are physical reasons for fused material to spread like a donut due to surface tension forces because of the radial temperature gradient.
    Smaller dot sizes could probably be obtained with a 1.6W laser due to overall lower temperatures and smaller focus point, but I have not performed such tests with these slurries. 

    Please also note that real work speed would in fact be lower due to acceleration/deceleration curves. Therefore for working with vector images, additional optimization of parameters might be necessary.

    After that you can export the toolpath to the Snapmaker Luban Workplace, transfer the file to your instrument over Wi-Fi (recommended), adjust the origin point and start the process. For this particular picture on a tile of 200 mm × 200 mm, it took around 7 hours.

     

    ___18.png

    Ceramic Tile Post-Treatment

    ___19.png

     

    Wipe the excess of dried slurry with a wet cloth or paper towel and discard it. Wash the tile with water and dish soap, then rinse it with water. Let the tile dry at room temperature from both sides.

    And it is done!

     

    ___20.png

     

    Multiple Colors

    An external photo editor can be used to separate color layers and those layers can be processed and dithered separately, giving individual pictures for each of colors in the whole project.

    By using guiding rulers attached to the platform, the tile can be repositioned exactly the same way for each color and the same work origin can be set.

     

    ___21.png

     

    It is important to let the tile dry completely each time before applying a new layer of slurry to avoid the influence of the water absorbed in the ceramic tile during washing.

     

    __20221017-063247.jpg

  • How to Engrave a Clear Picture

    Engrave_a_Clear_Picture.jpg

    Hello, Maker!

    It's time to put your laser engraving and cutting machine into practical application! To unlock the potential of your machine, let’s begin with one of the laser’s most basic applications, engraving pictures.

    In this episode, we would like to go through the whole process of laser engraving a picture with you, including material preparation, picture selection and editing, and work parameter configuration.

     

    1. Prepare a Material

    In the previous episode, Material Selection Guide: How to Choose a Proper Material for Laser Processing, we have introduced some commonly used materials for laser processing and the principles for material selection. Ensure that the material is safe for your health and the environment and that your machine is capable of engraving it. In addition, to engrave a clear picture, we recommend you use a material that has the following features:

    • Flat top surface

    As a picture is two-dimensional, it can only match a flat surface. If you engrave a picture on an uneven object, the result would be distorted. Besides, a laser engraving and cutting machine usually works with a fixed focal length. During engraving, a level surface enables consistent focusing, and thus guarantees uniform engraving effects.

    mceclip17.png

    • Fine and smooth surface

    A fine and smooth surface allows more details of a picture to be presented. If the material you want to use doesn’t feel smooth, you can try to polish it. Avoid using porous materials; otherwise, the result will be blurry.

    mceclip1.jpg

    • Light color

    Generally, the laser beam engraves materials through burning and makes the surface of the material darker. When engraving on a light-color material, the differences between the lightest and the darkest area could be more prominent, allowing more color gradients to exist in between.

    mceclip2.jpg

    Based on these considerations, we choose basswood, which meets the above requirements and is inexpensive and easily accessed, to demonstrate the process of laser engraving a picture.

     

    2. Select a Picture

    Picture selection is key to the success of laser engraving. A picture with high resolution and contrast would be our first choice since it contains more minutiae and objects in the picture are more distinguishable. Besides, to retain more details in the engraving product, it would be better to use a picture that includes a lot of transitions from light to dark and doesn’t contain large blocks of solid color.

    Understanding the reasons why we choose a picture that has a high resolution, high contrast, and rich color gradient without large blocks of solid color, now let’s see how we can identify a qualified picture.

    • High resolution

    Image resolution is the detail an image holds. Images are made of tiny pixels (picture elements), or squares of color. Image resolution can be measured in pixels per inch (PPI) or dots per inch (DPI).

    mceclip1.png

    High-resolution pictures are at least 300 PPI or 300 DPI, appearing sharp and crisp. This resolution makes for good print quality and is pretty much a requirement for any picture that you want to reproduce.

    Just because a picture looks good on your computer screen doesn’t mean it has high resolution. You can’t tell by the length-width dimensions, either. Heavy file size can be a clue, but not in all cases. A simple way to check image resolution is to open up the picture in an image program and view the file properties. You don’t need a fancy program to do this; most computers come with a basic image editing program that will do the trick.

    • High contrast

    Contrast is the degree of difference between two colors or between the lightest and darkest areas in an image. A high contrast picture features a big difference between light and dark, while a low contrast one has colors close in tone. If a picture is plain white, there are no differences in its color, thus the contrast is zero.

    Although it seems easy to distinguish the light from the dark in real life, it may become a little bit tricky when it comes to a static picture. Take the following two pictures as an example, can you tell which one has the higher contrast?

    mceclip3.jpg mceclip4.jpg

    Picture 1 has the higher contrast. Have you got the right answer? Here is a simple way to help you find the contrast differences between pictures:

    (1) Prepare a screenshot software.

    (2) Respectively cut out small squares of the lightest and the darkest areas from the selected picture. Then, juxtapose the light and the dark squares, so that you can easily see the contrast.

    mceclip5.jpg

    (3) Repeat Step (2) on another picture to get its contrast samples.

    mceclip6.jpg

    (4) Compare the contrast samples from different pictures. The larger difference between the lightest and darkest squares from a picture, the higher contrast the picture has.

     

    • Rich color gradient without large blocks of solid color

    When engraving a picture, the laser cannot reproduce color. Instead, it creates different levels of light and dark by controlling the amount of energy emitted, and thus recreates the picture. With a lot of transitions from light to dark in a picture, the monochrome engraving product will be more vivid. Conversely, if a picture contains too many large blocks of solid color, the engraving result may appear flat and dull.

    mceclip7.jpg

     

    3. Edit the Picture

    The purpose we edit the picture is to emphasize the subject and sharpen the edges, producing a clear and distinctive engraving result. It does not require a lot of complex photo editing skills to achieve the effects we want. The operations we need to perform on the picture mainly include cropping, adjusting contrast and brightness, sharpening. You can use any photo editing program that includes these basic functions. Here we use the free open-source raster graphics editor, GNU Image Manipulation Program (GIMP) for demonstration. Now, let’s open the picture in the editor and get started!

     

    (1) Crop the picture

    Crop the picture based on your need.

    mceclip8.jpg   →  mceclip9.jpg

     

    (2) Desaturate the background

    By fading the background, we can avoid background overpowering the subject. In some cases, if you don’t need the background, you can also directly remove the background.

    First, we need to isolate the main subject from the background. We can do this by using the free select tool to trace the subject out.

    Then, select the background, reduce its contrast and make it lighter.

    mceclip11.png

     

    (3) Reduce the shadows

    Shadows usually cause darker burning during laser engraving. If there are too many shadows on the main subject, it may cause the final engraving product to look dirty.

    Select the main subject, and then adjust its shadows and highlights. By increasing the exposure of the shadows and adding more highlights, we can get rid of some heavy shadows.

    mceclip12.png

     

    (4) Sharpen the subject

    After adjusting the shadows and highlights, the overall color of the subject appears bright. But this is still not the final effect we want. To make a distinct engraving, we need to make the edges more clearly defined.

    First, add more contrasts, to make the lines of the subject more pronounced again.

    Then, sharpen the image, making the image looks crisp.

    mceclip14.png

     

    Finally, we get the picture suited for laser engraving. As you can see, compared with the original image, the edited one has a weakened background and a well-defined subject. Now we can save the picture and export it as a .png file. If you use other image editing programs, be careful not to compress the picture when saving it.

    mceclip16.jpg    →  Engraving_Object-edited_2.jpg

     

    4. Start Laser Engraving

    Here we come to the last step, engraving the picture on the selected materials. Depending on the laser engraving and cutting machine you use, the procedure for starting laser engraving may vary. In this step, we will use Snapmaker Luban to transform the picture into a G-code file and use Snapmaker 2.0 1.6W Laser Module to do the laser engraving job.

     

    (1) Import the picture to Snapmker Luban

    After you import the picture to Snapmaker Luban, you can resize and rotate it, adjust its position on the coordinate, and transform it to a greyscale image.

     

    (2) Select Movement Mode

    When creating the toolpath, you can select the Movement Mode, including Dot-filled Engraving and Line-filled Engraving. Dot-filled Engraving takes more time but results in a more detailed image. To pursue a better engraving quality, we use Dot-filled Engraving as the Movement Mode.

     

    (3) Set Laser Power and Dwell Time

    Both the Laser Power and Dwell Time directly affects the engraving result. The higher the Laser Power and the longer the Dwell Time, the darker the engraving color.

    We can use the control variate method to find an optimal combination of Laser Power and Dwell Time. The engraving pattern with the darker color and without excessive charring or depression on the workpiece surface is the best result.

    mceclip14.png

    Finally, we set Dwell Time to 5 ms/dot, and Laser Power to 30%.

     

    (4) Set Fill Interval

    As we have already known, Fill Interval is the distance between the dots constituting the engraved pattern. If the Fill Interval is too large, the engraved pattern will be light-colored and might lose some details; if too small, the dots will overlap, making the engraving color too dark and the pattern indiscernib

    mceclip3.png

    We need to run tests to find the best fill interval. Engrave a series of squares with different dot intervals and record the interval with the clearest diagonal texture as the optimal interval.

    mceclip16.png

    Based on the tests, we set 0.14 mm as the Fill Interval.

     

    Note:

    Snapmaker Luban has preset values for some material, which are tested and recommended.

    For more information about how to test and set work parameters, refer to the following articles:

    Parameter Configuration Guide: How to Set Proper Work Parameters for Laser Engraving and Cutting

    The Definitive Guide to Laser Engraving and Cutting with the Snapmaker

     

    (5) Generate the G-code file

    After configuring the work parameters, save the toolpath settings and generate a G-code file in .nc format.

     

    (6) Start laser engraving

    Transfer the G-code file to the laser engraving and cutting machine. Put on laser safety goggles, and we are ready to go!

    For more information about how to use Snapmaker 2.0 1.6W Laser Module, refer to its Quick Start Guide, User Manual, or video tutorials.

     

    Disclaimer

    The methods on material selection, picture selection and editing, and laser engraving discussed herein are for reference only.

    Snapmaker assumes no liability or responsibility for any property loss, personal injury, machine damage or expenses incurred by the methods on material selection, picture selection and editing, and laser engraving discussed herein or in any other means related to such methods.

     

  • Parameter Configuration Guide: How to Set Proper Work Parameters for Laser Engraving and Cutting

    Set_Parameters_for_Laser.jpg

    Hello, Maker!

    In the previous two episodes of Snapmaker Academy about laser, we have learned where we can get templates for laser engraving and cutting, and how we should select proper materials for laser engraving and cutting. In this episode, we are going to learn how to set parameters for laser engraving and cutting. Without further ado, let’s get started!

    This article will introduce you to the work parameters for laser engraving and cutting. First, we will learn what they are and how they work. Then, we will learn how to perform parameter test to find the optimal combination of parameter values.

     

    Crucial Parameters for Laser Engraving and Cutting

    Laser Power

    Laser Power controls the amount of energy in the laser beam. It can be set as a percentage between 0% and 100%. In laser engraving, the higher the Laser Power, the darker the engraving color. In laser cutting, a laser with higher power can cut deeper, but it will also result in seriously charred edges.

    Only with sufficient laser power can we engrave a clear pattern or cut through materials. However, excessive laser power may also cause trouble. It is crucial to keep the Laser Power parameter within an appropriate range.

    Work Speed/Dwell Time

    Work Speed refers to the moving speed of the laser toolhead during laser engraving and cutting. When Laser Power is set to a fixed value, the faster the toolhead moves, the shorter time the laser beam stays on the workpiece, and the less laser energy the workpiece absorbs. Therefore, in laser engraving, when the other parameters remain unchanged, the higher the Work Speed, the lighter the engraving color. In laser cutting, the higher the Work Speed, the shallower the laser cuts, and the less charred the cut edges.

    Dwell Time refers to the time for which a laser spot emitted by the toolhead stays on the workpiece during laser engraving and cutting. In laser engraving, when you select the Dot-filled Engraving mode, you can set Dwell Time. Both Work Speed and Dwell Time are used to control the time for which the laser with a fixed power stays on the workpiece, thereby controlling the laser energy absorbed by the workpiece. The shorter the Dwell Time, the lighter the engraving color.

    Both Laser Power and Work Speed (Dwell Time) are vital to the effect of laser engraving or cutting, as they control how the workpiece is engraved and cut. When testing work parameters, we usually adjust Laser Power together with Work Speed (Dwell Time) to determine an optimal combination, as the two parameters can restrict and affect each other.

    Fill Interval

    Laser engraving features two modes: One is the Line-filled Engraving mode, in which the pattern is formed by engraving lines; and the other is the Dot-filled Engraving mode, in which the pattern is formed by engraving dots. Fill interval is the distance between lines or dots.

    In the Line-filled Engraving mode, the Fill Interval defines the distance between the lines comprising the engraved pattern. If the Fill Interval is too large, the engraved pattern will be light-colored or even discontinuous; if too small, the lines will overlap, making the pattern too dark or blurred.

    mceclip0.png

    In the Dot-filled Engraving mode, which follows the similar principle as the Line-filled Engraving mode, the Fill Interval is the distance between the dots constituting the engraved pattern. If the Fill Interval is too large, the engraved pattern will be light-colored and might lose some details; if too small, the dots will overlap, making the engraving color too dark and the pattern indiscernible.

    mceclip3.png

    This is how the two modes differ: When you set the Fill Interval in the Line-filled Engraving mode, you only need to focus on the interval between each line and its adjacent line, but in the Dot-filled Engraving mode, you need to consider the interval between a dot and all of its surrounding dots. Therefore, the Fill Interval configuration in the Dot-filled Engraving mode is more complex, and you need to first determine the parameters including Laser Power and Work Speed, and then fine-tune Fill Interval between dots until you find a parameter range for the best engraving effect.

    Number of Passes

    Number of Passes is a required parameter in the Cutting Mode. To cut through a thick workpiece, multiple cuts are required on a fixed path. This parameter determines the number of cutting passes on a fixed path.

    Generally, the laser beam emitted by the laser toolhead is in the shape of an inverted cone, and the focal point has the highest laser energy and cutting ability. To ensure that the focal point of each cut falls on the workpiece, the laser toolhead will lower by a certain height each time Number of Passes is increased so that the laser focal point can reach the workpiece. However, the laser toolhead cannot be lowered to a height where it is too close to the workpiece surface. Otherwise, the toolhead may bump against the workpiece. As the laser cuts deeper, the laser beam will be blocked by the workpiece on both sides, and the laser energy reaching the cutting position will taper off until it is unable to cut through the workpiece. Therefore, Number of Passes cannot be increased without limit.

    mceclip4.jpg

    How to Find the Optimal Work Parameters

    To determine the optimal combination of work parameters, we have to run a certain number of laser parameter tests, and adjust the parameter values according to the working principle of laser parameters.

    The Snapmaker Laser Engraving and Cutting Machine can perform laser operations in the following three modes: Line-filled Engraving mode, Dot-filled Engraving mode, and Cutting Mode. In the following section, we are going to learn how to test the work parameters under these three modes.

    Line-filled Engraving Mode

    In the Line-filled Engraving mode, the machine engraves lines to form a pattern. The engraving effect is mainly determined by three work parameters, namely, Fill Interval, Laser Power, and Work Speed.

    Line Fill Interval Test

    The thickness of a laser-engraved line is determined by the diameter of the laser spot falling on the workpiece. With accurate focusing, the diameter of the laser spot emitted by the Snapmaker 2.0 1.6W Laser Engraving and Cutting Machine is 0.20 mm, so the width of the laser-engraved line is also 0.20 mm.

    mceclip5.png

    Theoretically, if the engraved line is 0.20 mm thick, the lines with an interval of 0.20 mm can fitly cover the engraved surface without overlapping each other and form a complete pattern. However, in laser engraving and cutting, the effective area of the laser beam may be diffused. To avoid edge overlapping and prevent secondary engraving, a 0.05-0.10 mm buffer area is usually reserved between the lines. Therefore, a line interval of 0.25-0.30 mm is recommended.

    It should be noted that when the line interval is greater than 0.30 mm, the color of the engraved pattern will theoretically become lighter, and the lines may even diverge. However, in this case, if engraved lines remain thick and greatly overlap, the focus may be inaccurate or the Laser Power may be too high. You just need to refocus or lower the Laser Power.

    Click the icon below to get the test template for Fill Interval in the Line-filled Engraving mode:

    mceclip7.png

     

    Laser Power and Work Speed

    Both Laser Power and Work Speed are variables. In parameter tests, we can assign a fixed value to one variable and fine-tune the other until we find the best engraving effect. Here, we set the Work Speed v1 to 500 mm/s and line interval to 0.25 mm, and we make Laser Power the only variable. We then increase Laser Power stepwise to engrave a series of 10 mm × 10 mm squares on the workpiece surface.

    mceclip8.png

    From these squares, we select the one with the best engraving effect on the principle of "clear lines and no excessive charring", and record the power W1 corresponding to the result.

    Theoretically, the engraving area on the workpiece (S), the energy absorbed by the workpiece surface (E), Laser Power (W), the engraving time (t), and Work Speed (v) can be expressed with the following equations:

    E = W * t

    t = S/v

    Therefore, E = S * W/v, indicating that Laser Power W is directly proportional to Work Speed v.

    In the first test, we have found that when Work Speed is v1, the power corresponding to the best engraving effect is W1. To maintain the best engraving effect, E cannot be changed. Through the theoretical formula E = S * W/v, we can infer that if Work Speed is increased to v2, the engraving power must be increased to W2 in proportion so that E can remain unchanged.

    However, the relationship between W and v may be affected by many other factors and is not necessarily in strict direct proportion. Therefore, after we infer the possible Laser Power corresponding to a Work Speed using the theoretical formula, we need to run more tests to ensure we can get the best engraving effect.

    Click the icon below to get the test template for Laser Power and Work Speed in the Line-filled Engraving mode:

    mceclip10.png

     

    Dot-filled Engraving Mode

    In the Dot-filled Engraving mode, a pattern is created by laser spots. The engraving effect is mainly determined by three work parameters, namely, Fill Interval, Laser Power, and Dwell Time.

    Laser Power and Dwell Time

    The way to test Laser Power and Dwell Time in the Dot-filled Engraving mode is similar to that in the Line-filled Engraving mode. First, we assign a fixed value to both Dwell Time and Fill Interval. Here, we set the Dwell Time t1 to 5 ms/dot and the Fill Interval to 0.14 mm. Then we fine-tune the value of Laser Power, and we get a series of squares.

    mceclip14.png

    In the Dot-filled Engraving mode, the criterion for the best engraving effect is the darker color without excessive charring or depression on the workpiece surface. During the engraving process, the relationship between Dwell Time t and Laser Power W is E = W*t (E is the energy absorbed by the workpiece for each engraved dot).

    In the first spot engraving test, we record the optimal Laser Power W1 corresponding to Dwell Time t1 and calculate the optimal combination of Dwell Time and Laser Power at other Work Speeds through W1*t1 = W2*t2. Then, through further tests, the optimal parameter values are determined.

    Click the icon below to get the test template for Laser Power and Dwell Time in the Dot-filled Engraving mode:

    mceclip11.png

     

    Dot Fill Interval Test

    The difference between the Dot-filled Engraving mode and the Line-filled Engraving mode is that the former uses dots to form patterns while the latter uses lines. In the Line-filled Engraving mode, we only need to focus on the interval between the lines in the vertical direction, while the Dot-filled Engraving mode requires us to consider the interval between dots in all directions. Therefore, we first find an optimal combination of Laser Power and Dwell Time through parameter tests, and then run further tests on the Fill Interval to get the best engraving effect.

    mceclip15.png

    The method to test Fill Interval is to adjust the interval between dots and keep other parameters unchanged, so we can get a series of 20 mm × 20 mm squares with different dot intervals.

    mceclip16.png

    For these squares, the clearer the diagonal texture, the better the engraving effect. We record the interval with the clearest diagonal texture as the optimal interval.

    Click the icon below to get the test template for Fill Interval in the Dot-filled Engraving mode:

    mceclip13.png

     

    Cutting Mode

    In the Cutting Mode, a workpiece is cut by the high-energy laser beam. The cutting effect is mainly determined by three work parameters, namely, Laser Power, Work Speed, and Number of Passes.

    Laser Power

    In laser engraving, there is theoretically a direct proportion between Laser Power and Work Speed, which is also true for laser cutting. To maintain the same cutting effect, Work Speed needs to be increased accordingly with the increase of Laser Power. In addition, when you set Laser Power to a higher value and adjust Work Speed accordingly, you can get clearer and smoother cut edges with less charring.

    Therefore, in laser cutting, we generally use 100% Laser Power, and control the laser energy by adjusting Work Speed.

    Work Speed and Number of Passes

    When Laser Power is determined, we need to adjust Work Speed to control the effect of laser cutting. To ensure that the workpiece can be cut through, we also need to set a proper value for Number of Passes. We can run cutting parameter tests through a matrix of Work Speed and Number of Passes. We stepwise increase values of Number of Passes and Work Speed, so that we can get a series of small squares on the workpiece, as shown in the figure below.

    mceclip17.png

    It can be observed that under the same Number of Passes, the higher the Work Speed, the thinner the cut gap; at the same Work Speed, the greater the Number of Passes, the thicker the cut gap. To get the best cutting effect, we should find the square with the thinnest cut gap on the premise that it is cut through.

    The criterion for the best cutting effect is that the squares are cut through with the minimum Number of Passes and the highest Work Speed. If the values of multiple results are close to each other, the one with the least cut-through time is the best.

    Click the icon below to get the test template for Work Speed and Number of Passes in the Cutting Mode:

    mceclip12.png

     

    Recommended Work Parameters for Laser Processing

    After a series of tests, we have obtained the optimal parameters for engraving or cutting a variety of materials. We hope these recommended parameters can help you take laser engraving and cutting in stride. For details, see the article “The Definitive Guide to Laser Engraving and Cutting with the Snapmaker”.

     

    Disclaimer

    The parameter test methods and recommended parameters discussed herein are for reference only.

    Snapmaker assumes no liability or responsibility for any property loss, personal injury, machine damage or expenses incurred by the parameter test methods and recommended parameters discussed herein or any other means related to such methods and parameters.

  • Material Selection Guide: How to Choose a Proper Material for Laser Processing

    Choose_Material_for_Laser.jpg

    Hello, Maker!

    After purchasing a laser engraving and cutting machine, you must be eager to dive into material processing. There are so many kinds of material you can use, including the most ordinary wood, paper, cloth, and leather. Adding a little design, you can recreate famous paintings on wood, cut flowers out of paper, or even produce fashion with a piece of cotton cloth.

    However, you cannot grab a piece of material from somewhere and begin laser engraving or cutting right away. There are still important issues you need to care about and methods you can follow in material selection.

    This article will provide you an overview of commonly used materials for laser engraving and cutting, and instruct you on how to choose a proper material for laser processing.

     

    Commonly Used Materials for Laser Processing

    1. Wood

    Wood is an organic material comprised of cellulose and lignin. When interacting with laser energy, partial combustion occurs inside wood. The primary factors affecting the laser processing results are the density, the uniformity of density, and the resin content of wood.

    Most people prefer to use wood with a low density, for it requires only a small amount of laser power, and the processing can be fast. The resin content of wood determines whether the wood burns are darker or lighter. If you engrave resinous wood with laser, for example, the same amount of laser energy can produce a darker color, resulting in higher contrast. But you should also be careful not to burn the wood too much or catch fire.

    The wood types that are commonly used for laser processing are as follows:

     

    Basswood

    mceclip0.jpg

    Basswood is a softwood with even texture and fine grain, so laser engraving and cutting stand out on this type of wood. Besides, basswood features a color of creamy white or pale brown, which makes it easy to paint, stain and finish after being laser processed. And it has a relatively high resin content, and therefore only low laser power is needed to engrave or cut a basswood. However, a thin basswood is prone to get distorted under the influence of moisture. To compensate for this drawback, thin basswood is usually processed to become plywood which tends not to warp or crack.

     

    Alder

    mceclip1.jpg

    As a soft and resinous wood, alder works great for laser cutting and engraving and produces a nice dark burn. The pale and inconspicuous color of alder allows for high-contrast engraved images, while its light grain doesn't take away the details of the patterns. The only drawback of alder is the possibility of the presence of knots, which may compromise the quality of the finished work.

     

    Cherry

    mceclip3.jpg

    Cherry has long been a popular wood for cabinet and furniture making in the United States. The wood of the cherry tree is considered a hardwood. The cherry wood comes with a light pink to dark brown color, straight grains, and a shiny texture. Products made from cherry wood are durable for use and nice-looking in appearance. Moreover, cherry is a flexible and smooth wood, making it an ideal choice for laser cutting and engraving.

     

    Plywood

    mceclip5.jpg

    Plywood is manufactured from multiple layers of thin wood veneer, which are bonded together with adhesive at high temperature to make composite sheet material. As a composite wood, plywood has a clean and light surface and does not easily deform when there are changes to atmospheric moisture levels. These properties make it an easy material for laser engraving and cutting.

    But fire or excessive smoke may occur during laser cutting due to the fact that plywood contains glue. Depending on the specific wood and glue used, the performance of plywood varies during laser processing. It is recommended to choose a plywood that is explicitly marketed for laser use. Birch plywood is a good choice as the most popular plywood for laser engraving and cutting.

     

    Medium-density Fiberboard (MDF)

    mceclip6.jpg

    Medium-density fiberboard (commonly referred to as MDF) is an engineered wood made by combining wood fibers with resin binders and then forming them into panels by applying high temperature and pressure. Mostly, MDF has a higher density than plywood. MDF can produce nice laser engraving results due to its smooth and firm surface. However, MDF does not suit laser cutting, for its glue content can result in charring or even toxic gases and fumes.

     

    2. Plastic

    Commonly used plastics can be mainly categorized into two types: thermosets and thermoplastics. The two types of plastics have distinct reactions with laser energy.

    For thermosets, their polymer chains have more connections and break down easily when heated. Thus, thermosetting plastics cannot be successfully melted without damaging the molecular structure and the material changing color. Laser engraving on thermosets can produce clear and high-contrast images. But to laser cut thermosets is not easy as this kind of plastic irreversibly hardens after its chemical structure changes.

    For thermoplastics, their polymer chains are simpler and have fewer bonding connections. Thus, thermoplastics can be melted easily without the polymer chains breaking down. When a high-energy laser beam impinges on a thermoplastic, the plastic melts down, accomplishing the cutting or engraving process. But since the melting process does not lead to color change, laser engraving on thermoplastics has inapparent effects.

    There is a wide range of plastics and quite a few of them can be laser processed, such as acrylic, POM, EVA, PA, PC, PE, and silicone. But it should be noticed that every plastic more or less releases toxic gases, so it is vital to work in a well-ventilated space, install a filter system, and put on protective equipment.

     

    Acrylic

    mceclip0.png

    Acrylic (PMMA), also known as plexiglass, is a thermoplastic used as one of the most common materials for laser cutting. Acrylic cuts nicely and safely, plus its rich color options, therefore becoming the best plastic for laser cutting. There are two types of acrylics manufactured through different methods: extruded acrylics and cast acrylics. Extruded acrylic cuts smoothly with a clean and flame-polished edge. Cast acrylic produces a frosty white color under laser processing, allowing for breathtaking laser engraving patterns.

     

    Delrin

    mceclip1.jpg

    Delrin, also known as Polyoxymethylene (POM), is a thermoplastic that excels in durability, stiffness, and dimensional stability. These exceptional features make it one of the most common materials for manufacturing wear-resistant products like gears and bearings. Besides being rigid, Delrin is also more ductile than acrylic and wood, therefore promising more accurate laser cuts. The cutting edge is so smooth that it requires no further finishing. That said, laser cutting Delrin will release pungent fumes and easily catch fire if the laser power is high.

     

    EVA Foam

    mceclip3.jpg

    EVA (ethylene vinyl acetate) is a copolymer of ethylene and vinyl acetate. This kind of thermoplastics is an extremely elastic material with low-temperature toughness, stress-crack, and UV radiation resistance. EVA foam has a closed-cell structure and retains excellent flexibility and resilience. When you cut an EVA foam with a laser, the cutting kerf will be wide due to the heat melting process, and the color of the cutting edge will be slightly changed into light brown. However, if you laser engrave an EVA foam, the material surface will become tacky and finally get a darkened color.

     

    3. Fabric

    mceclip4.jpg

    Most types of fabric are suitable for laser cutting, while some fabrics, such as felt and fleece, can be processed by laser engraving as well. Commonly used fabrics for laser processing include cotton, linen, nylon, silk, and wool products.

    It requires only a small amount of energy for laser to engrave on or cut fabrics. The precise machine control process allows for multilayer and intricate designs, producing detailed and elegant clothes that enjoy great popularity in the fashion industry. But the most conspicuous advantage of laser interaction with fabrics is contactless processing. Laser cuts are accomplished without any pressure on the fabric, therefore ensuring no rough edges or fraying. Moreover, the high-energy laser beam can create clean and sealed edges after cutting. All these characteristics guarantee the superiority of laser technology in the fabric processing industry.

    Although most fabrics can be cut well by laser, use caution when you cut materials that may be plastic coated, impregnated with plastic, or that are made from PVC. These materials are likely to catch fire or release gases that can damage your lungs and your machine. 

     

    4. Paper

    mceclip5.jpg

    Paper types are diversified and can be categorized based on multiple different standards. Nonetheless, the most commonly used paper types for laser processing are writing paper, paperboard, and corrugated paper. As paper is usually thin and light in weight, laser engraving on paper may not work well, but laser cutting is most suitable for this kind of material, for it is efficient and energy-saving. That’s why large numbers of businesses are using laser cutters to create bespoke paper products such as wedding invitations. 

     

    5. Leather

    mceclip6.jpg

    Traditionally, leather products are handmade or assisted by electric tools. But because leather is such a strong and durable material that leather processing can be time-consuming and inefficient, coming with fewer pattern choices. The emerging of laser processing helps to address those problems.

    When a highly contrasted laser beam hits on the surface of leather, it quickly vaporizes or burns the leather. Laser engraving leather results in a debossed effect and a noticeable and clean contrast. Cutting leather with laser is incredibly fast and precise, making intricate designs easy to produce.

    Most natural leathers can be safely engraved or cut with a laser machine. However, you need to be careful not to use artificial leather. Artificial leathers are typically made from PVC, which can release poisonous gases when being heated, damaging your machine and your health.

     

    Principles for Material Selection

    A laser engraving and cutting machine is so versatile that material selection becomes complicated and full of possibilities. After you know about the general features of commonly used materials, you may still be confused when faced with practical laser processing. Are there any universal principles that can guide you through the evaluation of every material? There certainly are! In this section, we will further describe the following two principles you must follow in choosing a proper material for laser work:

    • Put safety first
    • Consider machine capability

     

    1. Material Safety

    To laser engrave on or cut a material, the first thing you need to care about is safety. Essentially, laser burns, melts, or vaporizes materials to achieve the desired effects. Being exposed to high-energy laser beams, the physical and chemical properties of materials are subject to change. It is possible to produce sticky liquid, flame, or poisonous fumes and gases if an inappropriate material is used, and consequently damaging your machine, harming your health, or polluting the environment. To avoid dangerous situations, always research on the properties of the material you want to use and learn about its possible reactions under the influence of laser, or more specifically, high temperature.

     

    Materials You Should Never Use for Laser Engraving or Cutting

    • Polyvinyl chloride (PVC)
    • Acrylonitrile Butadiene Styrene (ABS)
    • Epoxy
    • High-density polyethylene (HDPE)
    • Polystyrene foam and polypropylene foam
    • Flame-retardant materials

    PVC: Releases chlorine gas that is highly corrosive. Chlorine gas will cause serious physical injury to humans and damage to the machine.

    ABS: Melts when heated, creating a gooey mess. Emits toxic cyanide gas.

    Epoxy: Prone to catch fire and produce toxic fumes.

    HDPE: Melts and catches fire easily.

    Polystyrene foam and polypropylene foam: Melts and catches fire easily.

    Flame-retardant materials: Typically contains bromine, which is corrosive. Skin tissues will be damaged if they get in contact with bromine.

    There are so many more dangerous materials and possible harm that we cannot list them all. To protect the machine as well as your own safety, you should get familiarized with the material properties and pay attention to the usage notes of each material.

     

    2. Machine Capability

    After you determine that a material is safe to be laser engraved and cut, the next aspect you need to evaluate is the capability of your machine. Is your laser machine capable of engraving or cutting the material you choose? To answer this question, you must factor in the two elements: laser wavelength and laser power.

     

    Material Absorption of Laser Wavelength

    A lasing medium, also called gain medium, describes the material used to generate laser emission (stimulated emission). Each lasing medium produces laser beams at a very specific wavelength with a particular power level. The shorter the wavelength of light, the higher will be the energy it contains.

    Laser machines can be categorized based on the lasing media they use, and lasing media determine the wavelength of the laser.

    mceclip1.png

    Although light with a shorter wavelength comes with higher energy, it does not mean the shorter the wavelength, the better the laser performance. Every material has a characteristic absorption spectrum. For example, silver fir absorbs light at a wavelength of around 1000 nm better than light with wavelengths ranging from 800 to 900 nm, as shown by the following pictures.

    mceclip1.jpg

    Therefore, you do not necessarily need a laser machine that emits light of the shortest wavelength to accomplish the best laser processing effect. To choose a laser engraving and cutting machine, you need to take into consideration lots of elements such as the machine size, application, and price. Different types of laser machines have their own strengths and weaknesses. As long as you choose the right materials that suit your machine, you can create astonishing works. Back to our discussion on laser wavelength, every type of laser machine emits laser beams of a specific wavelength, while each material has a different absorption rate on different wavelengths of light. Therefore, based on the laser wavelength your machine produces, choose materials that have a good absorption rate on the laser light so as to ensure higher quality and faster processing results.

    The following table provides a reference on how to choose materials based on laser wavelength.

    Machine types

    Commonly used materials for laser processing

    CO₂ laser engraving and cutting machine

    (10.6 μm)

    Paper, wood, fabric, plastic, leather, rubber

    Semiconductor laser engraving and cutting machine/Laser diode

    (400–1064 nm)

    Paper, wood, fabric, plastic, leather, rubber

    Fiber laser engraving and cutting machine

    (1030–2100 nm)

    Stainless steel, carbon steel, galvanized steel, copper, aluminum

    Green laser

    (532 nm)

    Green laser is typically used to make laser pointers that do not have engraving or cutting function

    UV laser engraving and cutting machine

    (355 nm)

    Paper, wood, fabric, plastic, leather, rubber, ceramic, glass, metal

    (UV light has a high absorption rate on nearly every material.)

     

    Laser Power and the Density and Thickness of Materials

    Laser power is measured in Watts. The more watts, the more powerful the laser is. A laser engraving and cutting machine with higher laser power has wider applications. This is because the laser power of a machine is adjustable. A higher maximum power allows for a wider adjusting range, therefore resulting in more diverse applications. Normally, laser machines sold to individual consumers have a laser power of up to 120 Watt. Machines with higher laser power are mostly used in industrial manufacturing.

    Laser power is one of the most important factors that determine what kind of materials you can use. The required energy and necessary wattage vary depending on the material being engraved or cut in relation to that material’s density. A material with a higher density will need a more powerful laser for engraving and cutting.

    In particular, for laser cutting, material thickness also depends on laser power. More laser power can produce deeper cuts. Without sufficient laser power, a laser machine cannot cut through very thick materials. As shown in the following picture, a thick material requires multiple cuts. Each time the laser head starts the next cutting pass, the laser height automatically lowers for a certain distance so as to ensure the focal point always falls on the destination surface. However, the laser head cannot go down without limit since it will eventually collide with the material surface. Moreover, as you cut deep into a material, the cone-shape laser beam will be partially blocked by the materials on the two sides of the cutting kerf. When the laser goes through the narrow kerf and finally reaches the destination, it becomes weak and less powerful until the material eventually fails to be penetrated.

    mceclip3.jpg

    The following table provides information on the minimum laser power required to process some commonly used materials.

    mceclip0.png

     

     

  • Templates and Designs for Laser Engraving and Cutting: Great Websites and Software that Will Make You A Better Creator

    Great_Websites_and_Software.jpg

    Now that you’ve owned this beautiful, powerful, and wonderful laser engraving and cutting machine, you are probably wondering what you can do with it. Sit tight. In this article, we are going to show you the application of the laser engraving and cutting machine, the websites to find inspiration as well as access templates, and software for designing.

     

    What Can You Do With A Laser Engraving and Cutting Machine

    Engraving and cutting? Yes, and more. Yes, you can use this machine to engrave on or cut materials, but what you can do is way beyond that! 

    A laser engraving and cutting machine uses a high-power laser to accurately engrave on or cut materials on designated paths based on machine instructions. It is a manufacturing tool that can make your designs come to life. To operate this powerful machine, you just need to take the following steps:

       (1) Download a template for laser engraving and cutting from the internet, or design one by yourself.

       (2) Edit the template using graphics editors.

       (3) Import the design into CAM software (such as Snapmaker Luban) to generate a G-code file.

       (4) Transfer the G-code file to your machine and start engraving and cutting.

    By using a laser engraving and cutting machine, you can not only engrave or cut materials based on 2D designs, such as pictures, patterns, logos, and silhouettes, but you can also create 3D objects, such as gift boxes, 3D puzzles, and lampshades.

    • 2D Creations

    mceclip0.jpg

    • 3D Creations

      mceclip1.jpg

     

    Where to Find Templates for Laser Engraving and Cutting

    Website

    Feature

    Application

    1. 3axis.co

    Large repository, Creative and practical designs, Free

    Cutting

    2. Laser Ready Templates

    One-stop shop, Rich themes

    Engraving, Cutting

    3. Etsy

    Large variety, Detailed descriptions

    Engraving, Cutting

    4. Thingiverse

    Community, Free

    Engraving, Cutting

    5. Dreaming Tree

    Cardstock materials, Festivals

    Cutting

    6. Library Laser

    Home decorations

    Cutting

    7. Free Patterns Area

    From easy to complicated, Free

    Engraving, Cutting

    8. Ponoko

    Electronics enclosures, Free

    Cutting

    9. So Fontsy

    Novel and fashionable designs

    Engraving, Cutting

    10. Boxes.py

    Template generator, Customized parameters, Free

    Cutting

    11. Vecteezy

    Massive resources, Convenient search engine, Free

    Engraving, Cutting

    12. Maker Union

    Lively patterns, Free

    Engraving, Cutting

    13. The Hungry Jpeg

    Crafts, Fonts, Graphics, Templates

    Engraving, Cutting

    14. Pinterest

    Image sharing, Social media

    Work Display

    15. ArtStation

    Art showcase platform

    Work Display

     

     1. 3axis.co

    ____-_1.png

    3axis.co is a large repository of laser cutting designs and other vector files. You can find templates for various objects, such as gift boxes, lampshades, rocket models, clocks, chessboards, wall decorations, and many more. All of those are creative and practical designs that will definitely add fun to your life.

    Tags

    Cutting, Wide variety

    File Formats

    BMP, CDR, DXF, DWG, PDF, STL

    Number of Files

    20,000+

    How to Obtain

    Download

    Registration

    Not required

    Cost

    Free

     

    2. Laser Ready Templates

    ____-_2.png

    Laser Ready Templates is a one-stop shop for laser engraving and cutting templates. The on-shelf designs cover a number of themes, such as animals, nature, kids’ stuff, festivals, fashion, and nostalgia. In the description of each template, you can get an idea of the materials suitable for your creation.

    Tags

    Engraving, Cutting, Art, Life

    File Formats

    AI, CDR, DXF, EPS, PDF, SVG

    Number of Files

    5,000+

    How to Obtain

    Add to cart and pay to obtain

    Registration

    Not required

    Cost

    Free, with paid files available

     

    3. Etsy

    ____-_3.png

    Etsy is a global online marketplace focused on handmade items and craft supplies where you can find a large variety of laser engraving and cutting templates. Type in “laser engraving and cutting” and click the search button, plenty of designs for laser machining will pop up within seconds. Click any design you like, and you will be able to see the template description as well as other customers’ reviews.

    Tags

    Engraving, Cutting, Wide variety

    File Formats

    AI, CDR, DXF, EPS, PDF, SVG

    Number of Files

    63,000+

    How to Obtain

    Add to cart and pay to obtain

    Registration

    Not required

    Cost

    Paid resources

     

    4. Thingiverse

    ____-_4.png

    Thingiverse is an idea-sharing community that encourages creations, especially 3D printing creations. Laser engraving and cutting projects are also featured on this site. As an active community, this site features downloadable templates, as well as vibrant comment section where you can review other people’s work and share yours.

    Tags

    Engraving, Cutting, Creative

    File Formats

    AI, BMP, CDR, DXF, PDF, STL, SVG

    Number of Files

    4,000+

    How to Obtain

    Download

    Registration

    Not required

    Cost

    Free

     

    5. Dreaming Tree

    ____-_5.png

    Dreaming Tree is an online shop that sells laser cutting templates. Most of the designs use colorful cardstocks as the materials, presenting themes that mainly involve festivals and celebration. With those templates, you will be able to create brilliant and lovely works that remind people of fairytales and childhood. For each design, you can also find attached a useful assembly tutorial and material list.

    Tags

    Cutting, Cards, Childhood, Festivals

    File Formats

    SVG

    Number of Files

    740+

    How to Obtain

    Add to cart and pay to obtain

    Registration

    Required

    Cost

    Paid resources

     

    6. Library Laser

    ____-_6.png

    Library Laser is a repository of laser cutting templates. It operates as an online shop but offers a large number of free templates. The cases displayed on this site mainly apply to home decoration and model creation. With those templates, you will be able to make elaborate and practical works, enriching your life with laser creations.

    Tags

    Cutting, Decorations, 3D models

    File Formats

    AI, CDR, DXF, PDF, SVG

    Number of Files

    1,200+

    How to Obtain

    Add to cart and pay to obtain

    Registration

    Required

    Cost

    Free, with paid files available

     

    7. Free Patterns Area

    ____-_7.png

    Free Patterns Area offers a collection of vector files and laser cutting templates. The website divides its resources into two categories: 3D project files and 2D vector files. 3D project files can be used to create 3D objects through laser cutting and assembling. 2D vector files are relatively basic graphics. You can choose templates from easy to complicated based on your need. Besides, this website also contains free software resources for you to download and edit your designs.

    Tags

    Engraving, Cutting, Vector graphics, 3D models

    File Formats

    DXF, DWG, EPS, PDF, PNG, STL, SVG

    Number of Files

    200+

    How to Obtain

    Download

    Registration

    Not required

    Cost

    Free

     

    8. Ponoko

    ____-_8.pngPonoko provides free laser cutting templates, especially those for electronics enclosures. It distinguishes itself from other websites with various cases that combine laser products with electronics such as music players, computer racks for heat dissipation, and robotic arms.

    Tags

    Cutting, Electronics enclosures

    File Formats

    EPS, PDF, SVG

    Number of Files

    200+

    How to Obtain

    Click the image to download

    Registration

    Required

    Cost

    Free

     

    9. So Fontsy

    ____-_9.pngSo Fontsy is an online design and font marketplace where die cut crafters can purchase commercial use, cut-ready designs and fonts from designers who specialize in cuttable designs. Many talented designers have registered on this site and contributed thousands of novel and fashionable design templates. In the Laser Cut Files category, you can find awesome designs for laser cutting.

    Tags

    Vectors, 2D, Fashion

    File Formats

    SVG, PSD, PNG, EPS

    Number of Files

    100,000+

    How to Obtain

    Add to cart and pay to obtain

    Registration

    Required

    Cost

    Paid resources

     

    10. Boxes.py

    ____-_10.pngBoxes.py is an open-source box generator written in Python. It features both finished parametrized generators as well as a Python API for customization. After choosing your favorite laser cutting templates, you can set parameters such as material thickness, the format of processed file, the width of tabs, and burn correction and then click Generate to generate your custom design files.

    Tags

    Cutting, Boxes, Customized

    File Formats

    AI, DXF, G-code, PDF, PLT, PS, SVG, SVG_Ponoko

    Number of Files

    200+

    How to Obtain

    Set parameters to generate files

    Registration

    Not required

    Cost

    Free

     

    11. Vecteezy

    ____-_11.png

    Vecteezy is a large community for design and creation sharing. It boasts rich vector, bitmap, and video design resources, involving a wide range of themes such as backgrounds, characters, nature, travel, and food. Most of its designs feature a bright and vibrant style. To manage its massive resources, the site supports searching and filtering. For example, you can search for “laser cut” and set vector as a filter, then you will be able to find a large number of vector files for laser machining.

    Tags

    2D design, Bright, Simple

    File Formats

    AI, EPS, JPG, PDF

    Number of Files

    1,000,000+

    How to Obtain

    Download

    Registration

    Not required

    Cost

    Free

     

    12. Maker Union

    ____-_12.png

    Maker Union provides high quality designs in DXF format for engineers and manufacturers around the globe. Open this site, and you will be amazed by those sleek and lively vector graphics. Click and download a pack, and you will get a series of interesting designs under the same topic. All of those designs are perfect templates for laser engraving and cutting.

    Tags

    Vectors, 2D designs

    File Formats

    DXF

    Number of Files

    230+

    How to Obtain

    Download

    Registration

    Required

    Cost

    Free

     

    13. The Hungry Jpeg

    ____-_13.png

    The Hungry Jpeg is an online shop that sells tremendous design resources, including fonts, icons, card templates, menu templates, and so on. Whether you are a designer, crafter, newbie, or seasoned graphic design ninjas, you will be able to find the category that is useful for you.

    Tags

    Crafts, Fonts, Graphics, Templates

    File Formats

    DXF, EPS, JPEG, PNG, SVG

    Number of Files

    100,000+

    How to Obtain

    Add to cart and pay to obtain

    Registration

    Required

    Cost

    Free, with paid files available

     

    14. Pinterest

    ____-_14.png

    Pinterest is an image sharing and social media service designed to enable saving and discovery of information on the internet using images and, on a smaller scale, animated GIFs and videos, in the form of pinboards. Thanks to its popularity, this website is full of creative and smart designs. Try and search for “laser engraving and cutting”, and you will definitely be inspired by those fantastic creations. 

    *This website demonstrates finished works only. Design resources are unavailable.

     

    15. ArtStation

    ____-_15.png

    ArtStation is a showcase platform for professional artists to display their works and connect with opportunities. Designs and art can be showed in the form of images, videos, short clips, Marmoset and Sketchfab 3D scenes, 360 panos, and more. This platform enables users to build their own pages, customize their themes, and sell their designs.

    *This website demonstrates finished works only. Design resources are unavailable.

     

    How to Edit or Design Laser Engraving and Cutting Files

    Software

    Download URL

    Application

    1. GNU Image Manipulation Program

    https://www.gimp.org/downloads/

    Editing raster graphics

    2. Adobe Photoshop

    https://www.adobe.com/products/photoshop.html

    Editing raster graphics

    3. Inkscape

    https://inkscape.org/release/inkscape-1.1/

    Editing vector graphics

    4. Adobe Illustrator

    https://www.adobe.com/products/illustrator.html

    Editing vector graphics

    5. AutoCAD

    https://www.autodesk.com/products/autocad/overview

    2D and 3D drawings

     

    1. GNU Image Manipulation ProgramClipboard_-_2021-07-30_16.08.32.png

    GNU Image Manipulation Program (GIMP) is a cross-platform open-source raster graphics editor used for image manipulation (retouching) and editing, free-form drawing, transcoding between different image file formats, and more specialized tasks. Whether you are a graphic designer, photographer, illustrator, or scientist, GIMP provides you with sophisticated tools to get your job done. You can enhance your productivity with GIMP thanks to its rich customization options and 3rd party plugins.

    David Cardinal, an author at ExtremeTech, stated that GIMP "has become a worthy alternative to Photoshop for anyone on a budget who doesn't need all of Photoshop's vast feature set".

    Download URL: https://www.gimp.org/downloads/

    Cost: Free

     

    2. Adobe Photoshop

    Clipboard_-_2021-07-30_16.09.02.png

    Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc. for Windows and macOS. Photoshop supports editing and composing raster images in multiple layers and also features masksalpha compositing, and several color models including RGBCMYKCIELABspot color, and duotone. These are achieved through photoshop's unique PSD and PSB file formats. In addition to raster graphics, Photoshop has limited abilities to edit or render text and vector graphics (especially through clipping path for the latter), as well as 3D graphics and video.

    Download URL: https://www.adobe.com/products/photoshop.html

    Cost: Paid service, with a free trial of 7 days

     

    3. Inkscape

    Clipboard_-_2021-07-30_16.09.36.png

    Inkscape is a Free and open-source vector graphics editor for GNU/Linux, Windows, and MacOS X. It offers a rich set of features and is widely used for both artistic and technical illustrations such as cartoons, clip art, logos, typography, diagramming, and flowcharting. It uses vector graphics to allow for sharp printouts and renderings at unlimited resolution and is not bound to a fixed number of pixels like raster graphics. Inkscape uses the standardized SVG file format as its main format, which is supported by many other applications and web browsers.

    Download URL: https://inkscape.org/release/inkscape-1.1/

    Cost: Free

     

    4. Adobe Illustrator

    Clipboard_-_2021-07-30_16.09.54.png

    Adobe Illustrator is a vector graphics editor and design program developed and marketed by Adobe Inc. The industry-standard vector graphics software lets you create everything from web and mobile graphics to logos, icons, book illustrations, product packaging, and billboards. Adobe Illustrator was reviewed as the best vector graphics editing program in 2018 by PC Magazine.

    Download URL: https://www.adobe.com/products/illustrator.html

    Cost: Paid service, with a free trial of 7 days

     

    5. CAD

    Clipboard_-_2021-07-30_16.10.48.png

    AutoCAD is a commercial computer-aided design (CAD) and drafting software application. AutoCAD enables users to create precise 2D and 3D drawings. It is used in multiple industries, by architects, project managers, engineers, graphic designers, city planners, and other professionals. AutoCAD provides the following features:

    • Draft, annotate, and design 2D geometry and 3D models with solids, surfaces, and mesh objects.
    • Automate tasks such as comparing drawings, counting, adding blocks, creating schedules, and more.
    • Customize with add-on apps and APIs.

    Download URL: https://www.autodesk.com/products/autocad/overview

    Cost: Paid service, with a free trial of 30 days

     

     

    Disclaimer

    Snapmaker recommends the websites and software to you in no particular order and for resource-sharing purpose only. Snapmaker does not in any way endorse, control, or assume responsibility for the content, views hosted on and services provided by these websites.

  • Snapmaker Academy: How to Make a Laser-cut Lamp with Inkscape

    Laser-cut_Lamp.jpg

    In this article, we’ll show you how to make a laser-cut paper lamp using Snapmaker 2.0 and Inkscape software. If you are thinking about making a cool laser-cut project with some real-life scenes that you want to capture, well, this tutorial is for you.

    This tutorial is divided into five steps. Step 1-3 cover Inkscape operations, which come with three video clips for you to check out. Step 4 covers Laser-cutting and 3D printing, while step 5 demonstrates assembly and testing.

     

    You Will Need

     

    You Will Learn How To

     

    Use Inkscape to design patterns for laser-cutting, export SVG files that are readable to Snapmaker 2.0, and make a lamp. These include:

    • Tracing building outlines and details manually;
    • Tracing and simplifying bitmaps of complex objects;
    • Drawing simple patterns;
    • Laying out patterns and exporting them as SVG files;
    • Some common operations including:
      • [Left drag] Move object/ Select multiple objects
      • [Middle drag] Move canvas
      • [Ctrl+L] Simplify
      • [Ctrl+Z] Undo
      • [Ctrl+Y] Redo.

    Check out this page for more: en.wikibooks.org/wiki/Inkscape/Interface

     

    Steps

     

    Step 1. Draw the Outline of the Building.

    Operations include:

    • Set canvas size and orientation by going to File -> Document Properties;
    • Right click an object and choose Lock Selected Objects to avoid moving it accidentally;
    • Draw the outlines and windows of the buildings using Bezier Curve;
    • Fine-tune curves using Edit paths by nodes;
    • Arrange multiple objects by going to Objects -> Arrange;
    • Go to Path -> Combine to combine 2 or more objects into a unit.

     

    Step 2. Add Other Objects.

    Operations include:

    • Use Trace Bitmap and Fill and Stroke to trace outlines of certain objects automatically;
    • Go to Path -> Union to union overlapping patterns;
    • Use Bezier Curve to draw simple patterns;
    • Go to Path -> Exclusion to combine 2 objects by cutting off the smaller one;
    • Use Ctrl+L (Simplify) to smooth curves.

     

    Step 3. Export SVG Files.

    Operations include:

    • Use Bezier curve and rectangle tool to join certain patterns together into final shapes ready to be cut.
    • Lay out the layers apart on a new canvas;
    • Export SVG files that are readable to Snapmaker Luban software.

     

    Step 4. Laser-Cut and 3D Print.

    Now we can import the SVG files into Snapmaker Luban and move on to the laser-cutting part.

    It's recommended to set the laser parameters as follows:

    __-laser__.png

    When finished, generate G-code, send it to the machine and start cutting.

    01.gif

    The other parts of the lamp, including outer frame, interlayer frames and back panel can be 3D printed. Download the STL files here, (www.thingiverse.com/thing:4562693) import them into Snapmaker Luban, and adjust the direction of the model to lay it down on the platform. For the parameter setting, let's just select the Normal mode:

    __-3dp__2.png

    Now, change the machine from a laser engraver into a 3D printer and start printing. You’ll need:

    • 1 outer frame
    • 1 pack panel
    • 10 interlayer frames
    • 1 interlayer frame with a cable outlet

    02.gif

     

    Step 5. Assemble & Test.

    03.gif

    Stick the LED strips to the back panel with some hot melt glue, and fix the cable to the corner.

    04.gif

    Lay the outer frame flat, with its back facing upwards. Put the paper silhouettes in between each interlayer frame in the order of your designing, and press it down to make sure all the pieces are securely seated.

    You can also put in some extra frames to increase the height, if needed.

    Finally, put a piece of blank paper on the top, and then the interlayer frame with a cable outlet.

    05.gif

    Cover the back with the back panel, clip the cable to the outlet, and fix the panel to the back with some glue. Done!