Re: mach3 constant velocity
Mach3's CV mode (and trajectory planner) is severely flawed. Especially when 3D cutting.
CV mode's purpose, is to try to maintain the commanded feedrate (constant velocity). It does this pretty well.
The problem is that accuracy goes out the window, and none of the controls that should help control accuracy work all that well.
The best option is to increase acceleration as high as possible, if you're machine has the power to do so. Higher acceleration allows the machine to follow the path closer when directions change.
The second best option is to slow down, which has the same affect as increasing acceleration.
Even when you get it cutting really good, there are bugs in the planner that can result in small, random gouges in your parts.
A friend of mine makes small, precise wood parts, and could not get Mach3 to give acceptable results. He switched to UCCNC, and got better quality parts, 30% faster.