As new materials present themselves for laser cutting, you'll often want a quick approximation of the power levels necessary to get through the material. A simple test piece, in which cuts are made at different laser intensities, will help us do so. Fire up Inkscape (which can be downloaded here if you don't have it installed yet) to start designing the part, and start of by turning on the rectangular grid in order to greatly ease the process (
File - Document Properties - Grids).
Now draw the shapes you would like to cut as a test. I went with rectangles having rounded corners, made using the node edit tool found in the bar on the left side of the screen. Then the shape are patterned to have one for each of the power levels that are about to be tested (
Edit - Clone - Created Tiled Clones). I also added the cutting speed in question to the design, and might also add the lowest and highest laser intensity in the range at some point. After drawing a rectangle around all of these shapes, you could end up with something like the following.
In order to prepare the design for the software communicating with our laser cutter (named LaserCAD), the file is first saved in EPS format (
File - Save As) and then converted to DXF using the following command line tool:
pstoedit -dt -f "dxf:-polyaslines -mm" cutting-test.eps cutting-test.dxf. Next the resulting file can be imported in LaserCAD and different laser intensities attributed to each of the shapes. The latter is accomplished by individually selecting each of them and clicking a color at the bottom of the screen.Then, for each of the colors, cutting speed and power levels are set from the window at the right of the screen. Cutting speed is kept the same for all shapes, and power levels are raised in small increments. Next, send the file to the laser cutter (
Download) and test it on a piece of material. I keep a couple of such files handy for testing new materials, offering different combinations of cutting speeds and power ranges.