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Author Topic: Z axis moves on its own in program/jumps steps  (Read 6841 times)

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Z axis moves on its own in program/jumps steps
« on: October 07, 2006, 12:42:32 PM »
This is really becoming a problem for me  :( When im running a program the Z axis will move -ve direction and miss steps on its own + make a horrible sound. Once I left it for a few seconds and it had gradually jumped 10mm down into my vacuum table (not good) but still showed correct depth on readout. This happens nearly every program I run. Dont seem to have problems with X & Y steps jumping! I am running it all from a compaq presario 2100 (could this be the problem) Any help would be most appreciated. Cheers, Mark

Offline chad

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Re: Z axis moves on its own in program/jumps steps
« Reply #1 on: October 07, 2006, 01:29:26 PM »
Hi, this could be a bunch of things.
First make sure there is no binding in your z axis travel.
Second slow down your accl and velocity and see if that helps.
Third your z could be just to heavy for the size stepper you are using.
Fourth just for fun try increasing you step and Dir pulse width to 5us and see if that makes any diff.

The dro does not know if the motor stalled so they will always read the correct location. This tells me that mach is doing it's thing and the problem is in the hardware..

Chad
Re: Z axis moves on its own in program/jumps steps
« Reply #2 on: October 07, 2006, 06:21:50 PM »
Also you need to look and see that you don't have a problem with noise :) Do  you have shielded wires on the step and direction?
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: Z axis moves on its own in program/jumps steps
« Reply #3 on: October 07, 2006, 06:38:15 PM »
Not sure if I have shielded wires on step and direction Brian :-\ . How could I tell if I had a problem with noise? Is there a simple test? CNC router was new a few months ago from these guys (www.cnc-step.com) Seems like a well built proffesional piece of kit with CE approval and the like. The software that came with it was awful so I got mach3 which is fantastic to use :). I have tried adjusting the acc/vel & pulse width but to no avail.. Dedicated laptop what I run it from is an intel celeron 2.4 processor with 192Mb of ram. Not sure if this is sufficient or not? Cheers

Hood

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Re: Z axis moves on its own in program/jumps steps
« Reply #4 on: October 07, 2006, 06:43:00 PM »
As has been said above hardware rather than software is more likely your problem but I am curious to what operating system you have on your computer?

Hood
Re: Z axis moves on its own in program/jumps steps
« Reply #5 on: October 07, 2006, 06:45:21 PM »
It is running windows XP home edition, version 2002. service pack1  :)

Hood

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Re: Z axis moves on its own in program/jumps steps
« Reply #6 on: October 07, 2006, 06:48:08 PM »
I would say 192megs is a bit small for XP, it could be a problem but if you have been using it when you didnt have the problems then it is unlikely the cause.

Hood

Hood

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Re: Z axis moves on its own in program/jumps steps
« Reply #7 on: October 07, 2006, 06:50:13 PM »
As for fault finding with the hardware you could try swapping drives round to different axis and seeing if it follows the drive or stays with the axis.
Hood
Re: Z axis moves on its own in program/jumps steps
« Reply #8 on: October 07, 2006, 06:56:40 PM »
You mean reverse the Z axis into the Y axis on the controller? My X axis is driven by 2 stepper motors..I have kinda been having the problem with the Z axis twitching away from the word go.. The people I got the machine from aren`t really much help on technical problems and im not the best at speaking German hehe  ::) I figured I could try my new dell desktop as the driver test is perfect (it is not on the laptop) but it doesn`t have a parallel port!! Mark

Hood

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Re: Z axis moves on its own in program/jumps steps
« Reply #9 on: October 07, 2006, 06:59:40 PM »
Where are you from?
I am not sure how your control harware is set up or what type drives etc you have but there should be a way to swap the wires from one axis to another fairly easily.
Hood