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Wavy Cut on y axis only in one direction

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Jtucker7000
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Joined: Mon Jan 02, 2017 11:18 am

Wavy Cut on y axis only in one direction

Post by Jtucker7000 » Fri Feb 23, 2018 11:09 pm

I cut a piece yesterday and noticed only one side shows a wavy or jagged cut. It seems like to me the y axis is the cause but only when moving one direction, all straight edges along the x axis are smooth. I would think the problem would be present on the y axis regardless of the direction. The picture attached shows the difference, the left is wavy and the right is as good as it has ever been. Because its only one direction affected I assume its not the THC hunting or oscillating, and I wouldn't think its a gear and belt slipping, the rack and spur gear was replaced this year. I assume the issue is mechanical and I plan to spend tomorrow hunting for a solution, until then I thought maybe someone more experienced with this might have seen this before and point me in the right direction. Visually everything seems to be moving smoothly, this was cut with 45 amp fine cut consumables at 200IPM. Is my assumption that a mechanical issue is most likely? could a motor, driver, or electrical component cause this issue only when moving one direction?

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djreiswig
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Re: Wavy Cut on y axis only in one direction

Post by djreiswig » Sat Feb 24, 2018 10:10 am

If it is on the same side of the material it could be a nozzle problem.
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SeanP
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Re: Wavy Cut on y axis only in one direction

Post by SeanP » Sat Feb 24, 2018 2:42 pm

Was going to say gear rack until noticed you had replaced that, mine started showing signs on the X axis, my rack has had a fairly tough 4yrs and it's getting a bit worn, I ended up just sanding the outer edge of the spur gear, running smooth again now on mine.
It's worth disconnecting the belts and pushing the gantry it might help trying to spot it, did with mine.
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Re: Wavy Cut on y axis only in one direction

Post by jimcolt » Mon Feb 26, 2018 3:17 pm

If you put your hand on the torch while it is cutting you will feel a vibration in the direction where the roughness shows. Most likely it is mechanical, worn gears, incorrect gear mesh, loose or wobbly motor mount etc. It also could be a tuning issue....where one drive motor has an abnormally high gain or acceleration setting. Disconnect the motors from the gear....and push the machine on each axis as well to feel for binding. Jim Colt Hypertherm

Jtucker7000
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Re: Wavy Cut on y axis only in one direction

Post by Jtucker7000 » Tue Mar 06, 2018 11:38 am

I appreciate the advice, I’ve been so busy at work I just got a chance to do some testing. While the torch is moving everything feels smooth to me. I cut some 10ga and 1/4” at about 45 ipm and the cut is smooth both directions. I changed tips and not any better on 14ga at higher speeds. I’ve played around with motor tuning but I dont see any difference. The x and y are currently at 450velocity/35 accel, the z is at 40/10. My z axis uses bearings I believe made from delrin, I wonder at higher speeds if there is vibration there. If I push left and right on the slider there is a minimal amount of movement but I think it was always that way. I doubt plastic bearings would have very tight tolerances. Is it likely to be issues from the z axis? If so any suggestions on a good replacement. I’ve looked at the Velox makes it looks well made but bulky and exspensive.
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