Shifted Print

Ive been running into issues during printing of the print job shifting after several hours on my makerfarm i3v 12"
see attached photo

ive seen it shift, X sometimes and Y sometimes.
at first I thought the belt was loose and it it jumped a tooth or missed steps. but i check it and checked voltages and its fine. temperture on steppers is fine.
I have a strong fan blowing on my Rambo board, the stepper drivers are not overheating.

printer isnt running quickly.. 50mm/sec, jerk is 10, acceleration is 2000

its happened 4 times in a row.. sometimes the shift is huge sometimes its small.

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Makerparts.ca
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Have you checked the grub screw on your pulleys? I bet its shifted. Tighten it up, and make a flat on the motor shaft.

i did check and they seemed fine

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

Hi.
I have fight with a similar effect (not so a big shift , max was 1 mm) and at the end I found that
the nozzle make somtimes a collision on a needle(blob) on printet details in outline (holes or similar).

So it move my print surface (magnetic ficture) on the printer plattform.

JoRo

Seems fine or was fine? I only ask as this has all the symptoms of a mechanical failure, either belt slipping or pulley not driving etc. I would suggest removing the pulley to check, as with tight belts sometimes small grub screws slip and leave gouges in the motor shaft.

could it phantom end stop trigering, make sure wires from end stops are twisted and not running too close to motor wires(which should allso be twisted.

Can be a combination of things... like your smooth rods or rails getting a bit sticky.

Can also be the Pololu drivers have been set a little low to give the current needed to move the carriages accurately along stickier rods. Or maybe a little high even.

It might seem random, but I've noticed it tends to start happening as you begin printing larger models - middle of the bed area is nice and level, edges droop or soar up a little. Can be a sign of an unlevelled bed as well.

Its hard to see from the picture but is the shift occurring on the first layer that is trying to print the unsupported ribs sticking out the sides (at an angle).
No idea why this would cause an issue just looking to see if matches some geometry or operation change that might indicate its a slicing/Gcode issue. If you print the same part again do you get the exact same issue.

Print shifting usually affects the most massive axis (usually Y) most, but can affect both. If you've checked the mechanical stuff and ruled out loose pulleys and belts, check motor currents. If the current is too low you'll loose torque at speed. Do the motors feel cool after they've been running for a while? If slowing down fixes the problem, it's probably motor current. Turn it up. If it shifts at lower speeds, too, try turning down jerk and/or acceleration.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

OK I figured it out. As I saw it happen by chance 2hrs into a print. The nozzle/heated block has excessive petg buildup. The buildup touched a the print at one point with enough grab to make it skip steps. I took this opportunity to replace the heat block and nozzle with a new one that I had waiting for a rainy day with the new e3d silicone covers and Re ran the same geode and it printed perfectly.

Edited 1 time(s). Last edit at 10/28/2016 08:19AM by makerparts.

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Makerparts.ca
Your Canadian source for V-Slot Extrusion, CNC and 3D Printing Parts and Accessories.
we are proud to be an official Openbuilds distributor.

had similar issues. dismantle endstop wires from motor wires if you have them in a bundle. cross-talk is the issue