This issue is related to Fab Academy Week 03: Computer-Controlled Cutting.
Team
TODO
- Characterise your laser cutter focus, power, speed, rate, kerf, and joint clearance
Documented by Jasmine Xie
Build
characterized the laser cutter’s with my group:
We have an Epilog Laser 36T, 60W laser cutter in our Fab Lab. The manual is available here
- The type of laser is CO2 Laser 60W.
- The cutting area is 914 x 610mm.
- The maximum height is 305mm.
- It supports the following file formats: .ai, .cdr, .pdf, and .svg.
It supports the following line weights when engraving:
The typical workflow for using the laser cutter to cut is:
Software:
- Save your vectorized image as an .ai file and bring to the laser cutter
- Select all lines to be cut and set the stroke weight to 0.01mm and the color to R:255 (true red).
- Open the print dialog, go to Setup, and go to Preferences to open the Epilog Dashboard
- Select the Job Type, set the settings according to your local guide, correct the Piece Size, select Auto Focus, and Print.
- Select Print on the Preferences window, tick the “Ignore artboard” checkbox, ensure that the preview reflects a good place to print from, and select print.
At the laser:
- Follow this step-by-step guide.
focus
You can set the laser cutter to automatically focus the laser by ticking this box on the Epilog Dashboard:
It focuses at the first point of cutting. There is also an option to manually focus, which is available in the manual.
kerf
Oskar modeled a test for measuring kerf in OpenSCAD.
which included nine 20mm squares. We cut the file and measured each square (on both edges) and averaged the results, to come up with a measurement of 19.875mm. Subtracting that from the original spec of 20mm yielded a kerf of 0.125mm - this means that when you’re cutting a shape out, you need to add 0.125mm to the exterior of the shape to have an accurate cutout, and when you’re cutting a hole out, you need to make the hole 0.125mm smaller all around to have an accurate cutout.
joint clearance
Oskar performed a joint clearance test using this file, cut out of 4mm plywood:
The settings were 20 speed/75 power/500 frequency.
These were his findings:
- 0.15mm = Attachable by hand. Very loose.
- 0.1mm = Attachable by hand. Stays together but not permanent
- 0.07mm = Attachable by hand with difficulty. Stays together, hard to take apart.
- 0.01mm = Attachable by hand with difficulty. Stays together, hard to take apart.
He mentioned that a low negative clearance could be used to get a permanent press-fit joint that would need to be hammered together.