Triac Y axis error after G28/Toolchange

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GingerNinja54
Posts: 27
Joined: Mon 28 Jun , 2021 19:46 pm

Triac Y axis error after G28/Toolchange

Post by GingerNinja54 » Wed 04 Jan , 2023 22:30 pm

Hi all,
I’ve been having an issue with my Triac that I just can’t fathom!
At first I thought it was programming error on my part, but I’m quite sure I’m not to blame after all!!

I’m getting an intermittent issue that only seems to effect the y-axis.
Machine homes in XYZ with no issue.
After a G28/home/Toolchange *occasionally* when returning to position, I would get a deviation of approx. 5mm to the negative; i.e. tool at X0Y0, toolchange, return to X0Y0 by shown program position but physically returns to X0Y-5.0.
My datum stays constant so program position and machine position are shown correctly, but are physically out.
Re-homing out of program resets to correct position and X0Y0 is actually X0Y0.

I removed bellows and cleared swarf and chips from the casting and around the switch gear.
Cleaned it all, contact-cleaner applied to the micro switches and tested fine.
Positioning, toolchanging and repositioned fine, though didn’t get to ‘run in anger’.
Went to make a part tonight and had the same, but the Yaxis deviation was more like 10mm!!

Program is all centreline, with no comp. But I am running a 5mm slot drill.
I can’t see how it would be a factor, but for ‘full disclosure’.
(Though it did cross my mind…more than once!)

What and where do I start with getting to the bottom of this?!
Your help and advice is appreciated!!
Regards,
GN54

Toolmaker & milling specialist by day...
...bumbling idiot & 'Home-Engineer by weekend & night!
:D

Responses, support and advice is appreciated

Triac VMC (1995) With USB upgrade & VR Milling 5

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Steve
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Location: Denford UK

Re: Triac Y axis error after G28/Toolchange

Post by Steve » Thu 05 Jan , 2023 16:32 pm

It sounds like the Y axis is stalling at some point and loosing position.
Can you try running the program with the feed override set lower?
Check for any obstructions that may be restricting axis motion.
Has the machine been lubricated recently?

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GingerNinja54
Posts: 27
Joined: Mon 28 Jun , 2021 19:46 pm

Re: Triac Y axis error after G28/Toolchange

Post by GingerNinja54 » Fri 20 Jan , 2023 10:35 am

Thanks Steve,
I’ve narrowed it down to the problem coming when running to, or close to the Y- limit of Y-85.0mm.
It is only on occasion. Maybe 20% of the time.
It doesn’t seem to do it at lower feed, but not sure.
The stepper definitely makes a different sound when the error/skipping occurs.
I’ve run a proven program and in 2.5hrs machining had to re-home the machine after the error maybe 5-6 times.
It’s a real pain as I’ve lost faith in the machine and am scrapping parts.. 🙁
£10 material cost isn’t much, but 2.5hrs wasted time is a nightmare!!
I’ve put a lot of stops in the program so I can make sure I’m at the machine when it traverses to this position, but it’s not a great solution! 🤦🏼‍♂️

Any guidance is appreciated
Regards,
GN54

Toolmaker & milling specialist by day...
...bumbling idiot & 'Home-Engineer by weekend & night!
:D

Responses, support and advice is appreciated

Triac VMC (1995) With USB upgrade & VR Milling 5

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