[fseger]

I've had my 4'x4' router going now for about 3 months - not my first machine but my first mach 3 machine. It has seen about 100 hrs? of use without a problem( that I couldn't figure out). Last night I was running a program and it previewed OK - had a couple stray circles, but those have never cause a problem in the past. About 4000 lines in it plunged my Z axis straight down through my table. I was able to repeat this 3 times at the same spot( not close to one of the stray circles). I removed approx 20 lines of code and it pass right by. It was programmed by mastercam 7, which generates lots of G02,G03 arc commands.

Could mach3 be having a trouble with a arc command that causes the z axis to plunge like that. The strange part is - when I stop it right before it hits the table the DRO's are still at the old position.

Anybody else have this problem, what was a cure? Loosening the tolerances in Mastercam maybe so the arcs have a smaller radius?

Thanks
Fred

[neilw20]

Have you tried disastercam? It does the same. Also generates multiple moves in the same direction. That's enough to give the g-code processor so much to do that the queue gets emptied, while moving in a straight line. The cost might be proportional to the extra code. I love hand coding, or learning lisp.

[fseger]

Ok,
After some more testing I might have answered my own question. After posting out the files in line segments instead of arcs. I still had repeatable crashes - (always on the z which is weird). If I slowed down the program 25% if would run right by the lines of code that appeared to cause the crash. No the code problem then probably. Logged a couple CPU graphs. - appeared to be running about 80-95% when running full speed and about 50% when slowed down to 25-50%. At this point I think a "spike" is causing the problems.

FYI
Almost all the previous programs were run about 200 in/min and programmed by Artcam. This last batch is running 400-800 in/min and programmed by Mastercam.

Thanks
Fre