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losing axis zero point during job
« on: September 06, 2018, 10:52:00 PM »
I have a problem with my router losing its zero position, either x or y, during a job. The job seems to pause then move off somewhere else. I stop the job, raise the z axis then select return to zero and it returns to a point where either the x or y axis is not at the original zero. This can happen once or many times during a job or not at all. Can someone suggest what could be causing this behaviour?
I am using Mach3 on a laptop running Windows 10 with a USB controller. All the things they say not to do but I've created bigger jobs than my test one and I don't have the problem.
Until this morning it was always the y axis that was off but this morning it was the x axis each time.
Attached is the test file, created in Fusion 360, I've been using this morning and it crashed twice during one attempt losing the original x zero and each time it was off by a different distance.

Re: losing axis zero point during job
« Reply #1 on: September 07, 2018, 01:00:19 AM »
Hi,
one or both axes are loosing (gaining) steps.

The usual suspects if the machine is new and you are still dialling it in is excess velocity or acceleration.

If the machine has performed well for some time and then started playing up with the same settings
(velocity and acceleration) then I would suspect noise.

Almost invariably the spindle is the most electrically noisy device in the machine and almost certainly the most
powerful. Try running a job without the spindle running. Does it make a difference?

Craig
My wife left with my best friend...
     and I miss him!
Re: losing axis zero point during job
« Reply #2 on: September 07, 2018, 02:41:04 AM »
Thanks for your help. It is not losing steps as such it is just instantly changing the location of the x or y axis by up to 50mm. It just seems to pause then move to another position and continues as if nothing happened. When it does that I stop the job move the tool to the original zero position, reset all axes to zero then restart from abot 20 lines before the problem happened and it runs ok past the point at which the problem happened. It could happen again or it may complete the job without fault.
Because it is different each time I suspect it is caused by interference of some sort. When I pause Mach3 it continues for a while so I suspect the gcode is passed to a cache in the controller. I suspect the data in this cache may be getting corrupted by interference but it is only a guess. I was hoping to hear from someone who had experienced this problem.
Thanks again for your reply.
Re: losing axis zero point during job
« Reply #3 on: September 07, 2018, 03:25:49 AM »
Hi,
so you didn't bother to try running a job without the spindle running?

Craig
My wife left with my best friend...
     and I miss him!

Offline ger21

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Re: losing axis zero point during job
« Reply #4 on: September 07, 2018, 06:42:14 AM »
Quote
It is not losing steps as such it is just instantly changing the location of the x or y axis by up to 50mm.

It's probably stalling for a moment, and is 50mm behind when it starts moving again.

The most common causes are mechanical binding, or acceleration and velocity set too high.
Gerry

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