Messages

1

General Mach Discussion / Re: Help with Random Problem

« on: August 07, 2009, 07:40:00 PM »

Thanks for all the help.  After another day of fighting it, the problem answered itself - and it was nothing I suspected.

I was cutting some MDF this afternoon and the bit came out of the collet - twice.   I'd been cutting acrylic before that, and it was apparently only enough force to slide the bit down a little. 

Looks like a bad collet nut or a bad collet are to blame... replacements now on order!

Again... thank you.  This has been driving me nuts all week!

Dave

2

General Mach Discussion / Re: Help with Random Problem

« on: August 06, 2009, 03:25:27 PM »

Hi, Dave

First thing to try is reduce the Z axis Acceleration & Velocity values some in Config, Motor Tuning.

Chip

Thanks for the idea Chip - I actually did that as well, cut it all the way in half.  Still the same result...

3

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

4

General Mach Discussion / Re: Cuts getting progressively deeper

« on: June 13, 2008, 11:34:02 PM »

FIXED!  (I think...)

I only sort of understand what that setting means, but whatever it does, it works.  Just did 4 passes, depth and X/Y are dead on.

I did read that someone said it over rode the Step/Dir Pulse settings - the range listed is 0-5 and mine are set at 6?  No idea, just running the config the manufacturer includes... haven't really tweaked it any. 

This is a new machine for us (and I'm a noobie at CNC anyway) - I've been playing with it for a couple weeks building a prototype, but I was only cutting single parts.  Never really saw the issue until I went to cut a lot of them nested... 

Thank you all again, you saved a weekend of production time for us!!

Dave

5

General Mach Discussion / Re: Cuts getting progressively deeper

« on: June 13, 2008, 11:05:04 PM »

Scratch my last post. 

I just re-ran a path over itself 3 times (5 sets of 8 letters in the path), and it's drifting on the X and Y as well.  Something isn't right, and I have no idea what... either way, it looks like no prodution for me this weekend.

Is there some other setting in Mach3 I need to be looking at??

Dave

 

6

General Mach Discussion / Re: Cuts getting progressively deeper

« on: June 13, 2008, 10:32:43 PM »

Thank you both for the replies.

I took the covers off, everything seems snug and connected.  I also checked everything for binding, greased it all just in case and checked it over - no problems found.  There is a manual knob to move the Z, and the axis moves freely.

I got my machinsts micrometer out and did some testing... it drifts at 1 in/min2 just as much as on 8 or 12.  After 40 up/down moves it's off by about .02.  The other axes (axises?) seem fine - all of my letters are evenly spaced and sized - I didn't put the micrometer on the others, but the calipers seem to indicate X and Y are fine...

I'm not up for swapping out motors this weekend, so I guess I'll just break it out into small runs an re-zero in between each set... AAAAARGH.  Sounds like this stepper might be shot?

Any other ideas, I'd love to hear them!

Thanks again,
Dave

7

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