Intro: Using Inkscape to Prepare Images for Laser Cutting on FABOOL Laser-Mini for Screenprinting
Inkscape is a great tool for preparing images to be cut using the FABOOL laser mini and it's software. The main advantages are it's ability to separate into layers by color and to easily switch between bitmap and vector outputs. This is because the FABOOL software will print a bitmap image or a vector image, but it is much faster, generally, to print a vector image.
Step 1: Choose Image (using Google Images As Example)
- find an image on google images. Pick one that has no background, is one or very few colors, and try to avoid islands! Islands are pieces that when you cut the parts surrounding them, they will fall out when you want them to stay. For example, the middle of the letter "O" is an island, because you want to cut out the letter and have the middle stay, but it falls out because it's not connected to the rest of the picture any more.
- select the picture and on the popup screen, select view image. On the tab that opens with the image on it, right click on the image and click, "Save As" and save the picture. I do this instead of copying and pasting, because copying and pasting images with transparent backgrounds is problematic, and this way I have the original file, if I need it later on for whatever reason.
Step 2: Trace Image in Inkscape
- open inkscape, open a new document.file->document properties, set paper size to letter (if that's what you're using) and orientation to landscape or portrait.
- file->import, browse to the file you saved. Click okay on the following dialog box.
- select the image (it should be already selected), then path->trace bitmap.
- trace dialog--use the method your teacher suggests, but make sure you check "subtract background"
- drag the newly created traced object group off of the original image and delete the original image.
- place the traced object where you want it on the page, and size it using the handles on the active selection. Hold down ctrl to constrain to the same dimensions.
- If you 're going to print using multiple color screens, then using the bezier curve and line tool, draw a small two-line-segment corner just outside of the top left of the design. This will be your mark(s) to match up the pages (if you have multiple color screens). Copy that corner three times and rotate it to fit in the other three corners of the design (click a second time on a selected object and you get the rotation handles, again, hold down ctrl to constrain). Select all the corners that you have made and group them together (use shift key for multiple selection).
- select the traced object group (the image that you just generated with the trace dialog, not the crop-mark group you just made) and select object->ungroup. You should now have a set of grouped crop marks, and a bunch of color layers of your image (stacked up so they look good). Do any combining of layers that you have to at this point, so that you have the layers you want, but make sure that you wind up with the layered image positioned where you want it in reference to the crop marks.
Step 3: Evaluate Layers and Decide Bitmap or Vector Processing
Step 4: Vector Cutting, Split the Layers
- click on something in it to select the top layer, then hold down shift key and click on one of the grouped positioning marks, then type ctrl-c to copy them.
- create a new document, and set the document properties to the same as the original (e.g., letter size and landscape)
- paste the top layer with position marks and position on the page so that positioning marks are within page.
- save this as your_filename_top_layer_color.svg
- return to the original (with all layers) and select only the top layer (not the crop marks), and delete it.
- repeat this process, saving a file (with crop marks) for each of your layers with a different name (I like the fish_top_layer_black, fish_top_layer_minus_one_blue, fish_top_layer_minus_two_yellow naming scheme).
Step 5: Vector Cutting, Fix Islands
Okay, here is the beautiful part. If you have only a few islands, which you should, if you chose the vector cutting method of cutting your design, then you can subtract a mesh pattern from your design to connect any islands to their surrounding "land".
- In one of your layer files, draw a bezier shape (use the bezier tool, and make a shape that ends on the same node it starts on, and surrounds your island and connects it to the surrounding land. See figure for example.
- Hit space bar to switch to selection tool, then select the shape you just made, give it a fill if it doesn't have one, and hit ctrl-x to cut it.
- Open the screen5.svg (attachment, above) and paste in your shape. Position your shape over the crossed lines in the middle of the two groups of lines.
- Hit ctrl-a to select all, and then ctrl-shift-8 for path-intersection. This should result in only your shape being left, but filled with cross-hatch. Hit ctrl-c to copy that shape.
- Return to your layer .svg, and hit ctrl-v to paste in your shape, and position it where it was (surrounding the island).
- Hold down shift and click on another part of the layer .svg to select both it and the shape you just pasted in. Hit ctrl-minus (ctrl- -) for path-difference. This should subtract out the crosshatch pattern from your layer in the shape that you drew.
- Repeat this for each island. When you switch back to the screen5.svg, you can just click ctrl-z to undo the last shape and delete it, then paste in your new one. You can only difference two objects at a time, that's why you have to repeat this for each island.
Step 6: Prepare Layer for Cutting, Vector Layers
hit ctrl-a to select all objects on your layer (should just be your cut layer and the four crop marks).
Select fill-none and stroke-black.
Save your layer file.
Step 7: Cut!
Download and open the page_borders.svg file. select it and click in the width field, set width to 280 (mm). This will be your paper edges, to use as a guide. If your bed doesn't already have a set of marks for where to put down a piece of paper, then go ahead and cut this at full speed (3000), 100% power to mark your page frame on the bed. It would be good to test your laser at this point, to make sure it's cutting properly, since this will be very exact cutting.
Open your bottom layer .svg, and drag the corner resize handle until the bottom crop mark is just touching the inside of the page border frame (from the page_borders.svg).
Set the paper down exactly in the page frame and tape it down (at least I always do). Set the bottom layer .svg to cut at speed 600, power 100% and click the home button. Click the play button and watch the magic happen.
When it's done, label the paper with the color you're going to paint it, and with a pin and/or exacto knife, clean up the design, basically just making sure everything fell out that should have.