Layer shift in both X and Y after MM upgrade
 
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Layer shift in both X and Y after MM upgrade  

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Robert
(@robert-26)
Active Member
Layer shift in both X and Y after MM upgrade

For almost a year, I've been enjoying and really using my MK2 and I've printed hundreds of hours on it with very few problems, but after I did the MM upgrade last week, I've been getting a layer shift in almost every print - both multi-extruder and single-extruder slicing. I've generally been getting shifting on 3 out of 4 prints.

It's never the same layer - sometimes not even close, though it's often after an hour or so working on the same print. I haven't seen it happen, yet, or I'd have more of a clue. Sometimes there's an X shift; sometimes Y; sometimes both at the same time. On one plate of rather small parts (v-slot corner brackets), after printing a 10 or so layers perfectly, it Y-shifted, printed a few layers, then did both a Y and X-shift; a few more layers, then a final Y-shift. Then I noticed and killed the print. And always shifting towards the origin (X0,Y0), and usually by a millimeter or two, if that means anything, Y-shift is more common - maybe 5 to 1 Y-shifts for every X-shift. It happens in both driver modes: Silent and Loud. Before MM, I ran exclusively Silent mode and had no shifting.

Even though I didn't mess with the X/Y axis components during the MM upgrade, I've checked x and y belt tensions (same as always), cable obstructions (none), stepper drivers obstructed by the rearranged wiring and over-heating (no obstructions), loose connectors (none loose). The bed and hot end axis move freely - as they did before the upgrade. Self test passes and calibration is spot-on. I've lowered the xy travel speed, which seemed a bit faster than previous slic3r profiles, in case it was slipping on a too-fast travel.

I'm using the latest firmware (3.0.12) and drivers and the latest MM slic3r , and I'm using the single-extruder Slic3r mode for most of my slicing. (MM rarely, so far.) Doesn't seem to matter - I'm getting shifts on both.

If there's something else I can check, please let me know - my once-reliable MK2 work-horse is now unreliable and I can't depend on it.

Here's the multi-shifted corner bracket mentioned above. Y0 is toward the left of the image; X0 is toward the top:

Veröffentlicht : 09/09/2017 5:22 pm
AJS
 AJS
(@ajs)
Noble Member
Re: Layer shift in both X and Y after MM upgrade

Some common causes of layer shifting like this are listed here:

http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/-before-you-ask-troubleshooting-video-updated--t472.html#p39190

Check through those, and let us know what you find. We can help narrow it down from there.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 09/09/2017 5:35 pm
Robert
(@robert-26)
Active Member
Themenstarter answered:
Re: Layer shift in both X and Y after MM upgrade

Thanks for the reply, Aaron. I found that list referenced in another layer shift post and checked it out before posting here. None of those are the issue. The cat or ghost might have caused one, but the cat has an alibi for the others.

Veröffentlicht : 09/09/2017 7:38 pm
AJS
 AJS
(@ajs)
Noble Member
Re: Layer shift in both X and Y after MM upgrade

Does it do it on pre-sliced files also, or just the ones you sliced?

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 09/09/2017 8:43 pm
Robert
(@robert-26)
Active Member
Themenstarter answered:
Re: Layer shift in both X and Y after MM upgrade

The very first model I ran after the MM upgrade was the 4-color gear bearing pre-sliced gcode from the Prusa download site. It failed with a layer shift. I'd had several other post-build problems (filament not extruding because two of the metal tubes were wedged off-center by manufacturing debris in the multiplexor.) That layer-shift failure I chalked up as another post-build "breaking in" problem. I printed it again and it worked fine.

All subsequent prints have been from my sliced models - using the single-extruder mode of the latest Prusa - Slic3R - also from the Prusa download site. I've been printing (or attempting) plates of multiple, identical objects - part of a project I'm working on. I seem to have better luck on plates with a smaller number of objects with a tighter grouping - though that may just be because I'm printing fewer to save on waste if a layer shift occurs.

I haven't tried slicing a multi-color model yet or printing another Prusa gcode. MM printing is too "expensive" to trust until I can solve the layer shifting.

I came here hoping to find that it was a known problem with the current MM firmware or a rogue slicer settings. You know , wondering "Is it everyone or just me?" I see it is just me, at least in the MM group. I'll keep at it, and I really appreciate the debugging help. Thanks.

As an aside, or an additional data point, I recently (before the MM upgrade) had to repair four wires in the extruder bundle that had all broken against the edge of the large zip tie clamping all the cables to the back of the extruder. While the X and Y stepper wires aren't in that bundle, my printer has worked long enough to break some wires - maybe a few more on the printer are becoming worn as well. I'll give that a look, too.

Veröffentlicht : 09/09/2017 11:54 pm
AJS
 AJS
(@ajs)
Noble Member
Re: Layer shift in both X and Y after MM upgrade

Another thought.

You were in the Rambo box while doing the MMU upgrade. (I was!) It is cramped in there.

Check that your steppers seated well in their connectors. When you pulled and installed the extruder stepper you may have made one loose enough to occasionally skip steps. Even the crips on those connectors could be an issue.

Just thinking out loud.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 10/09/2017 3:05 am
Robert
(@robert-26)
Active Member
Themenstarter answered:
Re: Layer shift in both X and Y after MM upgrade

Appreciated, Aaron. I'll re-check the Rambo interior.

I'm about to dismiss the X-shift - I've only seen it once - and concentrate on solving the Y-shift. I had two more failed prints (Y-shift) last night. I've also noticed that if I arrange my parts-to-print along the X-axis and minimize long Y-travels, I don't get a layer shift - at least I didn't in the last three prints I arranged like that. ...something about the Y-travel may be involved. I'm also going to re-do my Y-axis belt - just for peace of mind. It may be too tight.

Thanks, again.

P.S. I've temporarily solved my problem by buying another Prusa MK2 kit. The new short lead times and the recent free shipping offer won me over. I can always use another workhorse printer. Surprisingly, my CR-10 has become my go-to parts printer while working on the layer shift problem and it's doing a very good job; it's not just for tall vases after all. 😮

Veröffentlicht : 10/09/2017 6:27 pm
AJS
 AJS
(@ajs)
Noble Member
Re: Layer shift in both X and Y after MM upgrade

I feel your frustration. My MK2 was running nearly continuously since I got it, and it has been a great workhorse for me. I upgraded to MMU last weekend, and it has been printing continuously since. I think i would be very frustrated in your shoes.

Hopefully you will find it soon (let us know - certainly others will have this same issue at some point) and you will be back to robust. For what it is worth, the multi-color prints have a much larger "impact" than I expected. A one color print looks nice, but somehow having more colors in the item makes it look completely different.

I expected that I would have to "start over" on the learning curve for the MMU, but so far it has been great for me. Designing things for the MMU has ben straight forward and the machine has worked great. I am sure I will hit snags soon, but so far I have been lucky. Current print is at 61:36 and has about 2.5 hours to go. Print looks fantastic.

Good luck.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Veröffentlicht : 10/09/2017 7:06 pm
stevehlau
(@stevehlau)
Trusted Member
Re: Layer shift in both X and Y after MM upgrade

Is your set screw on your x and y axis pinion gears secured? I did have a similar situation when I got my MK2, which I found out that my spool of filament tangle up and create a tension on the extruder to make the layer shift. I do not have the MM kit, but you might want to check that area as well. As I remember, the MM kit is a Bowden setup. So, check to see if something bind the extruder and create such tension. I am no expert, but that is what I can think of. Let me know.

Veröffentlicht : 11/09/2017 4:36 pm
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