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General Mach Discussion / Pocketing and Island avoidance issue, need help
« on: April 18, 2009, 09:56:53 PM »
Newbie using a home 'desktop' cnc. I've been at it hard for close to 2 months now and have been getting more advanced with some projects. This led me to my current problem and the software vendor says it's not their problem. I can cut Left, Right, on the line of circles, squares, whatever without issue and within a .002 tolerance all day long except for Pocketing with Island avoidance. In fact, take a simple 1" circle, put a .175 circle in the middle of that and tell it to pocket it and avoid the inner circle and I end up with .150 - .155, yet the outside of the pocket is 1.003 I can separately cut a .175 circle and be within .003
I have calibrated the system on X and Y it's within .001 - .002 (dialed in a 4" block measured at 4.279" and got 4.278"), backlash is the same, I can cut a 1" circle and measure all the way around and get 1.006 - 1.007. I've replaced the router with a better one and verified I do not have a runout issue with either the router or the bit. Again, this only happens on islands within pockets. My current workaround is to cut the raised island first with a slightly larger toolpath around it, then pocket specifying the larger toolpath for island avoidance to prevent it from getting whacked. If I do this same procedure without the larger toolpath, it will get cut down.
Anybody know why this is happening? Is it some configuration issue between the post processor and Mach3, or some setting in Mach 3? I'm new at gcode, but the simulation looks correct and the gcode looks correct, yet, it will eat into the island.
Appreciate any help on this.
Thanks,
Mark
I have calibrated the system on X and Y it's within .001 - .002 (dialed in a 4" block measured at 4.279" and got 4.278"), backlash is the same, I can cut a 1" circle and measure all the way around and get 1.006 - 1.007. I've replaced the router with a better one and verified I do not have a runout issue with either the router or the bit. Again, this only happens on islands within pockets. My current workaround is to cut the raised island first with a slightly larger toolpath around it, then pocket specifying the larger toolpath for island avoidance to prevent it from getting whacked. If I do this same procedure without the larger toolpath, it will get cut down.
Anybody know why this is happening? Is it some configuration issue between the post processor and Mach3, or some setting in Mach 3? I'm new at gcode, but the simulation looks correct and the gcode looks correct, yet, it will eat into the island.
Appreciate any help on this.
Thanks,
Mark