Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: studysession on September 24, 2012, 09:56:28 PM

Title: losing steps on z-axis (help)
Post by: studysession on September 24, 2012, 09:56:28 PM
Hi and I would greatly appreciate some help figure out why I lose steps or that is what I think is going on with my machine.....
I have this setup
https://www.finelineautomation.com/store/show/FLA100-00

with these electronics
https://www.finelineautomation.com/store/show/EL-0007

on X & Y I have 5 start screws and on Z I have single start screw.
during a job at some point the Z thinks zero is higher than it originally starts at. X & Y are perfect.

Thanks -
Keith
Title: Re: losing steps on z-axis (help)
Post by: RICH on September 25, 2012, 06:43:59 AM
Sounds like the Z is skipping steps. Experiment some, lower the max X&Y velocity.. Does this happen at a particular part of the code or is it random.
RICH
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 26, 2012, 04:34:38 PM
Been playing with the velocity settings like you suggested and still no fix.... :(

It is really odd - The z axis is always a bit higher at the end of the job than where it started. Where it thinks zero is changed almost every time.
Title: Re: losing steps on z-axis (help)
Post by: RICH on September 26, 2012, 05:20:52 PM
What kind of work are you doing?
Post your xml file.

What is "a bit higher"?
Do you have the steps per unit set accurately for the Z?

RICH
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 27, 2012, 04:09:23 PM
Will post my XML when I get back home along with everything I have about my setup. Thanks

A bit higher - The bit is no longer even touching the wood it was cutting to begin with.
Title: Re: losing steps on z-axis (help)
Post by: Fastest1 on September 28, 2012, 02:15:28 PM
Is everything clean in the Z platform/carriage? Does the ballscrew spin easily by hand (or have you checked?). I just discovered a similar problem in my mchine (and my bad technique for gib adjustment) however you appear to have linear slides so I have no idea if tension is adjustable simialr to gibs.
Title: Re: losing steps on z-axis (help)
Post by: Fastest1 on September 28, 2012, 02:16:41 PM
Is your plunge rate set too high and loosing the steps right away?
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 12:07:54 PM
Is everything clean in the Z platform/carriage? Does the ballscrew spin easily by hand (or have you checked?). I just discovered a similar problem in my mchine (and my bad technique for gib adjustment) however you appear to have linear slides so I have no idea if tension is adjustable simialr to gibs.

Simple answer is YES all is good in that aspect.
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 12:09:31 PM
Is your plunge rate set too high and loosing the steps right away?

No the first half of this particular job is perfect. And it is not consistent when it will start losing steps. I repeated the same job many times and it is not in same area where it loses steps.

This weekend I will be able to post some pics and my XML file.

Thanks
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 12:31:13 PM
I have this setup
https://www.finelineautomation.com/store/show/FLA100-00

with these electronics
https://www.finelineautomation.com/store/show/EL-0007

Attached is my zipped up XML file...

I have played with velocity and acceleration and regardless still same problem.
I have a single start screw on Z
and 5 start on X&Y

Thanks
Title: Re: losing steps on z-axis (help)
Post by: Hood on September 29, 2012, 12:57:33 PM
Set Mach to Sherline mode and see if that helps.
Hood
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 01:12:49 PM
Set Mach to Sherline mode and see if that helps.
Hood

Just set this and have same job re-running to see what happens.
Attached is the g-code I have been trying to run.
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 01:17:53 PM
By the time the job got from the right side over to the left side of the cut you can see where the finishing path was no longer touching to cut the wood. At that point it was almost 0.1 inch higher than where it originally started. There has been no consistency on where in the job it happens....
Title: Re: losing steps on z-axis (help)
Post by: Hood on September 29, 2012, 02:34:08 PM
Have you tried swapping around drives or motors?
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 02:36:50 PM
swapping around?? Unsure what you are asking??
Title: Re: losing steps on z-axis (help)
Post by: Hood on September 29, 2012, 02:49:38 PM
Swap the drive from one axis to another, for example X and Z and see if the problem follows to the X or stays with the Z.
Hood
Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 03:06:14 PM
Will do after this completes. I am running the finishing cut in the gcode files I uploaded.
I did the Sherline check box you suggested and see if it does anything to improve. Will post status once I figure it out from results.

THANK YOU!!!!
Title: Re: losing steps on z-axis (help)
Post by: RICH on September 29, 2012, 05:32:44 PM
Quote
There has been no consistency on where in the job it happens

That is why I asked if it was random. My guess is that  your Z can't keep up with your X & Y and it skips but not enough for it to completely go off on it's owne way. Had similar experience here when I started to do 3D cutting. Drove me bonkers, tried everything. In your case you may want to change the Z screw to the same as the X &Y and or get a different motor with more torque so the acceleration is improved.

FWIW,
RICH



Title: Re: losing steps on z-axis (help)
Post by: studysession on September 29, 2012, 05:57:10 PM
Looks like what I might need to do....

Not sure but sherline setting is making a difference. Not sure if it is now going deeper than higher like before.... Will tell after next couple of jobs. right now going to let code finish running it paths for the night then start again tomorrow.