Beam Dynamics Laser Cutter Tutorial
The CBA shop has a 4' x 4' Beam Dynamics laser cutter. This is a work-in-progress tutorial for their machine.
Wondering if your material is safe to laser cut? Check out Pololu's list of laser-cuttable materials
Creating a Drawing
1. Create the pattern you are going to cut using a drawing program like CorelDraw
2. Export your drawing in HPGL (.plt) format
If you must use another format, you can generate .dxf files that will open in LaserLink by importing a vector file into Rhino and then exporting it as a .dxf. Make sure all of the lines in your drawing are on the same layer and that your drawing contains no groups. Nested groups especially cause all sorts of problems in the LaserLink software. I cannot recommend using HPGL files strongly enough. I have had consistent inexplicable and frustrating software/firmware problems when using .dxf files.
Laser Link Software
3. Open the LaserLink software
4. Import your drawing
5. Editing your drawing
a) left mouse click
b) select the area of the drawing you want to modify
c) left mouse click again
d) right mouse click
e) left mouse click to begin your action (moving, copying, etc.)
6. Save your drawing.
7. Create the toolpaths for your drawing
b) Define the "process table", the laser cutter toolpath, for your drawing. Click on the "process table" icon. For each layer in your drawing, select the appropriate material. Here's the icon you click:
And here are the two windows you'll navigate through. In the first one, you select the layer you'd like to process and in the second one you select the cut settings for that layer:
c) Create the "process" by clicking the "process" icon or by clicking "process" after you've created the process table. Save the process file to: C:/BeamDynamics/JOBS.
8. Open the BeamHMI software
9. Home the machine
10. Load your job
11. Do a dry test run
12. Cut your job.
Note: the machine and software are pretty buggy, frequently exhibiting inexplicable behavior and errors. I've listed a few of the problems (& solutions) I've encountered below, but the list is by no means exhaustive. When in doubt, home the machine. If that doesn't work, cycle power. If that doesn't work, restart the software.
Problem: I press Start in the BeamHMI software, but nothing happens.
Solution: Home the machine and try again.
Problem: I press Start, and the head moves, but it doesn't cut.
Solution: Make sure the laser cooler is turned on and try again. If that doesn't work...
Home the machine and try again.
Problem: Motor head fault.
Solution: Turn off the machine, manually move the head around with your hands. Turn the machine back on. Home.
Problem: Focusing error/fault.
Solution: Home the machine and try again. If that doesn't work...
Move the Z axis up or down a bit using the controls in BeamHMI (Be careful not to crash the table into the head of the laser!). Home the machine & try again.
Problem: 1062 X Y Encoder Failure.
Solution: Power cycle the machine (turn the key to the off position, wait fifteen seconds, then turn it back to the one position). If that doesn't work...
If the failure always occurs when one axis of the machine reaches the same position (for example, whenever the X position is at 8.671 inches, when manually jogging around, regardless of the Y position), then there may be schmutz buildup on one of the optical position encoders. Cleaning of these encoders requires some disassembly of the machine, which the shop managers would be happy to help with. There are special tools required to do this properly, so please do not attempt this outside of normal shop hours.
Problem: Not cutting consistently (all the way through or same kerf width) across a large piece of stock.
Solution: Try grouping your toolpaths as individual processes for smaller areas, and set each of these processes to refocus. It will focus inside the bounds of the vectors for each process, which can correct for low frequency warpage of your stock material (and the honeycomb bed). If that doesn't work...
If the stock is warping because of the heat during cutting, you may have to strategize your cutting sequence in a more complex way, in order to allow the material to expand without popping out of the x-y plane. This will depend greatly on the geometry of the part. \\\