Topics

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General Mach Discussion / Help with Random Problem

« on: August 06, 2009, 03:10:33 PM »

Hi All,

I'm looking for advice on a problem that I just cannot seem to sort out.

I have a 4x8 CNC router, running Mach3 (recent version), stepper motors, 3 axis, 5hp spindle.

Over the course of, say, 100 cuts, my Z axis is cutting progressively deeper.  About .040"  Travel up and down on each cut is .500"

Here's what's really stumping me:  

It started doing it all of a sudden - no changes to my setup, just randomly started one day.

We cut a lot of the same thing over and over, so these are not new programs.

I've tried to rule out every variable - I can run the program in the air with no problem.  I can run it in the air with the spindle and compressor running with no problem.  I've tried every combination of things on and off.  It only seems to do it when I have "real" material being cut.

My original suspicion was the parallel cable - I haven't replaced it, but I cannot seem to induce an error by moving it, etc.  It's not crossing or touching anything with current in it.

I upgraded Mach3 from an old 2.6x version hoping maybe new drivers would help - no change.

I've greased, checked and rechecked all of my mechanical movements - all is smooth, no binding.

So, that's it... I'm stumped.  Software?  Machine?  Angry ghost in my shop?  Any Mach3 settings I need to check?


Thanks!

Dave

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General Mach Discussion / Cuts getting progressively deeper

« on: June 13, 2008, 06:23:17 PM »

Hi,

I've done some searching, and mostly come up short here... hopefully this hasn't been beaten to death already.

I'm running Mach3 R 2.63 on a dedicated WinXP machine, and an AccuCut XP series router from Computerized Cutters.  The machine uses steppers.  Z axis is ball-screw, the others are rack and pinion, and it's pushing a 5hp Perske spindle.

I'm cutting 28 sets of lettering into a 2x4 piece of acrylic, and each set becomes progessively deeper.  There are 8 letters in each cut, so 8x28=224 movements up and down.  Initial cut height is .01, and by the end I'm probably cutting closer to .04 or .05.

I can only guess this is a lost steps issue?  I've brought my Z speed down to 20, acceleration is at 4 in/sec2.

I verified the G Code and every cut has a Z of .0100.

The manufacturer is closed until Monday, so any help would be greatly appreciated!!

Cheers,
Dave