During the cnc build of a Longsworth chuck I ran into a cutting error that is baffling me.
I test cut this job some time ago and it worked fine.
I got a face plate and a new bit for plywood, made some mods to the design to “optomiz” the CAM. I also changed to a larger and better bit (1/4") and best I can tell that is when this problem started. Then I proceeded to cut the final material.
On the second arc it cuts the clockwise (G2) arc fine and then on the return (G3) it cuts a straight line vs returning on the same arcs path.
It cuts the center area (for face-plate) and the first arc fine. While cutting the second arc, on the first CCW arc it does not follow the arc, but rather a straight line back to its starting position. Subsequent arcs have similar albeit more complex forms of the same problem.
Its as if when cutting the second arc instead of a G3 move it just makes a linear move back to the start.
- It used to work…
- It makes the center clearing cuts (which are arcs) and the first large arc ok, these are G2-3 cuts.
- I haven’t changed the machine or the driving software
- I did change some CAM parameters and the bit size
- I glanced at the Gcode and I don’t see anything obvious yet, however its complex.
- All of the simulations that I have run with 3 different software’s do not show this error. Everything looks fine.
Answers to these questions would be helpful?
- Chilipeper does not follow the arc during a simulation of this job is this normal? Note: It does follow the arc path during actual cutting.
- Does anyone know of a bug or incompatibility that could be causing this. I reviewed all the tinyg supported codes.
- Ideas for troubleshooting???
- Dig into the Gcode in detail looking for a bug in the code although I have never dissected G2-G3 before :(!
- Separate the arcs into separate gcode files and just run the second arc, to simplify things.
- Go back to earlier versions and compare. This is tough as all the simulation tools do not show any problem.
- OX CNC
- tinyG controller
- Chilipepper driver
- Design/CAD in Fusions 360
My album for this project is here