Duet Firmware 1.22 XY Inaccuracy?
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Have you tried downgrade, for check its a firmware issue?
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@Phaedrux - I will give that a try.
@RCarlyle I was only thinking a firmware issue because the Duet I am using is an 0.8.5. As far as the Z Screw is concerned, it is an M5 .8mm thread. It sits on top of a gear that is bolted to the nema motor with a bearing for the center. When the Rod is removed, the gear has some play via the bearing center. The X Carriage itself is riding on a 12mm linear shaft with 2 bearings, and it is stabilized by a 40 x 80 extrusion where 2 10mm bearing "pinch" it. The X axis is moved by an m5 nut sitting in the X axis, so when the motor spin it pushes the X Axis up.
So I set out seeing what would happen if I mess with the threaded rod. It seems that is I push it to or away from the X axis, there is no movement. However, if I pull or push the rod parallel to the x axis it will cause a slight movement in the x axis. The rod, when it is raising or lowering the device does "wobble" (if I watch the top of the rod). I am going to flip the rod over and see if the unused side gives different results. As well as try your multi tower test.
@peirof - That would be my last resort. Going back to 1.14 would be a bit of work as I need to download and build the firmware myself, and then find the correct Duet Web Control to go with it.
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I really think this is a mechanical issue. As you said you've done some work on it recently in addition to the firmware update.
But if you wanted to test firmware without going all the way back to 1.14 you could try 1.18. I don't think it will help though.
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@Phaedrux I agree more now on the hardware. As I was reversing my threaded rod, I noticed the m5 nut that hold the carriage moves and wobbles quite a bit, unlike the m5 nuts that the gear was using to turn the rod. So, I have turned the rod upside down and swapped m5's just to see what happens. Tomorrow I will most likely hit the local metal shop and get a new m5 threaded rod and nuts and then figure out how to upgrade to a leadscrew.
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Thanks for the help. The problem has been found and partially fixed.
Tomorrow I will get a new M5 and nuts and see how it goes.
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Awesome. Now if only I can get my banding problem fixed.
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Wobbly Z Nut maybe?
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Something like that maybe.
https://forum.duet3d.com/topic/6618/help-me-solve-some-z-banding
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I see, with my z nut, I could literally move it up and down and wiggle it quite a bit.
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Any time you get banding, check whether the pitch of the banding exactly matches the pitch of the leadscrew or threaded rod. If it does, it's almost certainly caused by a mechanical problem.
