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Messages - Techvette

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1
General Mach Discussion / Re: Z axis craziness at program start
« on: November 08, 2017, 08:42:33 PM »
Try removing this line:

G28 G91 Z0.

And these two at the end.

G28 G91 Z0.
G28 X0. Y0.

That fixed the X and Y, Z is still off. BUT, you've given me a good idea of where to look.

THANK YOU.

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General Mach Discussion / Re: Z axis craziness at program start
« on: November 08, 2017, 05:33:49 PM »
I think this is a mistake. I operated this way for about a year and suffered quite a few crashes until I fitted
decent home switches. I reduced the number of crashes by over 95%. I now regard good home switches as a must.

I agree wholeheartedly, but that's a separate issue.

If run the gcode in a different simulator, and I see no out-of-bounds moves. The tool stays in the area I'd expect it to.  

But, when I load it up in Mach3 and look at the tool path tab, I see this:

.


Note the big vertical red line, which is about where the carriage tries to go when I run the program.




Note the "program limits" values, and the nice dotted red line going from the end of the last tool path to a point 54" south and 14" east.

I'm attaching the gcode in case anyone feels like looking at it and pointing out what I'm doing wrong. (SURELY this is my fault, but I'm at a loss as to how / why.)

Thanks for your time.




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General Mach Discussion / Re: Z axis craziness at program start
« on: November 08, 2017, 03:16:28 PM »
Viewing it in the simulator in Fusion does not show any of this. It only happens in Mach3.

And, as I stated, I'm zeroing it to the center of the stock, on the surface, before loading or running anything.

I don't have soft limits configured, and the homing switches are disconnected at the moment. But, cutting a 12x3x0.75 part on a 40x36x8 machine, from stock in the middle of the cutting area, with Mach zeroed to the center of the stock, shouldn't require limit switches. It should never try and move to a point 4' away that's not in the CAD and isn't a home location.

Unless I'm missing something really obvious.

I'll look at the gcode again, I suppose, but it'd surprise me if Fusion was generating this since I've set it to use the model origin, and the simulation doesn't show any of this.

4
General Mach Discussion / Z axis craziness at program start
« on: November 08, 2017, 02:02:09 PM »
I'm new to Mach3, and the search engine is failing me - apologies if this has been asked before. (If so, links are appreciated!)

Homebrew CNC with a C10 parallel breakout board, Win7, using fusion 360 for CAD/CAM.

When I load a g-code program, and look at the tool path limits, the upper Z limit seems to be randomly chosen by Mach3. For instance, when cutting a 3D contour from 3/4" stock, Mach3 initially tries to move the Z to +9 inches (this number changes from program to program). Note that my Z has an 8" travel, and a bad limit switch - disconnected at the moment - so I have to stop the program, jog Z, run the program, stop the program, send it back to the correct zero, and continue the program. This is entertaining on some levels, but frustrating.

The piece I'm talking about in this example scenario is less than 3/4" tall (height of the stock). Once I get past the initial step where Mach3 wants to move the carriage off of the top of the rails, it works relatively well.

I don't understand why it's trying to move the carriage all the way up by some weird value before going down again to start the cut.

This occasionally happens with X/Y as well. After cutting the part - in this case, about 12" x 3" - it wants to go to a point 4' away from the origin (which is in the center of the part I'm cutting). My machine isn't that big, so I have to make sure I'm near the stop button when the cut is done. There is no work to do at that location - it just likes to go there. Note that I zero all axes before starting the job, XY in the center of the stock and Z at the top of the stock.

So: WTF?

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