Sloping prints on Delta/Kossel

Hi All

I have owned a Micromake D1 Delta for some time and it has printed very well till now.
Recently it started printing on a slope towards one tower. Now it is jumping wildly as well.
I have tried:

Measured the endstop heights.
Rotated A4988 boards.
Rotated stepper connections.
Changed a stepper opposite the direction of slope.
Changed motherboard from Arduino/Ramps 1.4 to Makeboard Pro.
Added TL-Smoothers from Aliexpress to prevent spikes on the stepper cables.
Changed belt on one tower.

Still doing it in the same direction.

Any ideas? Getting desperate and running out of ideas in the bath!

Had that happen on my delta once, I'm using a v-wheel based motion system and it turned out the carriage wheels had come loose. If you've got linear rails, they might need lubricating, I'd suggest some form of silicone based lube, bit safer than some of the metal-based options.
hope that helps,
Cobalt Griffon

Many thanks for that. I will try that tomorrow. Best regards.

I've had a similar problem it's documented on here somewhere. It was the belts, the reinforcing in them had sheared in one place making them elastic. Belts should be replaced on a schedule dependant on how heavily the machine is in use or after a fixed time period a bit like motor oil.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Many thanks for the suggestion.
I did change one belt without success. I have now changed all the plastic pulley wheels as the old ones were a little stiff. Old oil possibly.
Jumping sideways every 2.4mm in height. Now tried switching slicer from Matterslice to Curaslice and the big steps have changed to 11.4mm!
The slope which appears very small now.

Check your drive pulleys are not slipping and you have flats on your motor shafts (grind some in if not). It's got to be mechanical. Change all your belts.

Edited 2 time(s). Last edit at 01/28/2018 07:29AM by DjDemonD.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Thanks again. They have flats and are tight. Will try the whole change of belts . Cheers.

I see more like skipped steps than sloped print? Since it always jumps in the same direction, you might also want to check your carriers. Bad bearing and such...

Many thanks for adding to this, o_lampe. I have replaced the bearings and wheels but had the same problem afterwards.
Now need to see if I have a weak driver again. Do you guys have Vref for the A4988s that you are using?