Originally Posted by
stevespo
a) wasting hours of my time
b) causing me to go prematurely gray and bald
c) a feature of BobCAD!
If you're not sure what these things are, they appear to be BobCAM V20 generated arc instructions with bad/bogus values that cause seemingly random circles to get created when trying to simulate or machine a part. Sometimes the simulation catches them, sometimes Mach catches them, sometimes you just ruin a part.
They may occur because of a chain gap, because an arc has a Z != 0 value, or for other reasons not known to me.
I seem to run into these almost daily. I plot/generate a series of 2d points, connect them with a spline, verify. Everything looks good. I generate my gcode, and then all heck breaks loose. I can reorganize, regenerate, etc - still random circles. I have played with my accuracy settings with little luck.
The only true "solution" I've found is to generate the splines as a series of straight lines (avoiding arcs entirely!). However, if I create an offset from this "straight line spline", sometimes arcs make their way into the new offset I've created. What a great feature that is! I want straight lines, I get arcs. If I then try and perform a pocketing operation, guess what? Crop circles!
Can anyone provide a consistent solution for this? Sometimes, I can generate my arc-based splines and everything works flawlessly. Other times, it's hours of frustration. I'd like to use arcs, because they generally create nicer looking curves and less gcode. I can't put my finger on what is different, or why it happens. Sometimes, I'm working in 2d, and I get very small Z values on my generated splines. I want Z=0, and get Z != 0. Bugs, bugs, bugs.
Sorry for the sarcasm,
Steve