I'm (trying) to run a real simple G-Code of a rectangle.  I put my part in the jig, get my work offset and make my first cut- everything seems fine.  I have about 60 of the same parts to cut so, I want to be sure they will all be the same so, I try to run the code again (on the part I just cut) and the X & Y axis have shifted (I would say about .125") to the negative axis.  In other words, I am now cutting too much on 2 sides of the rectangle (and not enough on the other 2 sides (I hope that makes sense).

At first I thought there was something funky with my code- so I checked and rechecked but, I don't think that's it (it's a frigging rectangle, there's not that much I can screw up).  I've tried re-referencing to Mach Coord Zero but, that didn't help.  It's the same story every time.  First cut is OK, then things start shifting. 

The motors don't sound like they are missing steps but, with the router runing I could just not be hearing it?

Anybody have any ideas on what might cause this?  Thanks in advance!

Sid

what is your step width (on the motor tune page)? try it set to 5 us and back down the  accel. If that is a no go we can try to changing you to sherline mode to give you a nice long pulse for the drive.

Hope that is some help
Brian

Brian,

As usual, THANK YOU VERY KINDLY for your prompt reply!  I tried changing the motor us setting to 5 but, that didn't really seem to change anything.  So.. I tried lowering my feed rate and that seems to make things better i.e. when my feedrate is high, the cuts are not accurate.

 It's almost as if Mach3 is putting out more pulses than my stepper drive is capable of sending to the motors.  Could this be true?  Is there anything I can do about this.  My feed rate is so painfully slow right now that I can almost take a nap in between cuts.  Would the Sherline mode help me?

Thanks again,
Sid

I think it would

Thanks!  I tried that and things seem better but that could all change in an instant  .  I'm wondering if maybe I have a problem with my Driver Board?  Could a bad driver board cause problems like this?

Sid

Is enhanced pulseing enabled?  I had a similar kind of problem with medium to fast feedrates and it turned out that it was disabled (dont know how as was previously enabled)
Hood

What do you have for drives?

Hood- Thanks for the suggestion!  I'll check it out after lunch (right now the only advanced pulsing going on is my heart rate)

Brian- here's a link to the driver board I have ... http://dtllc.com/4xcnc10b.html

I think it that driver just needs a long step pulse... Can't tell from there Doc's

Thank You!