HELP! Shifted and Warped Prints  

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matt.m5
(@matt-m5)
Active Member

I have had my printer and made upgrades from a 2S to a 2.5S. I printed with PLA and PETG in my upstairs office consistently with absolutely no issues.
As of recent, I moved my printer to my basements and my prints have started shifting and warping. The warping is especially terrible with PETG, but now it’s getting worse with PLA!

What in the world is going on?!?

I’m only experiencing shifting in the X-axis, and warping happens whether I include brim or not. I’ve checked the X-axis belt and pulleys and they’re both secure. I never had shifting or warping when I printed in my upstairs office, but even when I moved the printer back upstairs I experienced warping. Can someone explain how to fix this?

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Posted : 04/06/2020 4:01 pm
erik.t2
(@erik-t2)
Active Member

Can't help you with the layer shifts, but I have a terrible problem with warping in cooler weather in my basement. I have an enclosure even, but my basement gets down to 10-12c in the winter (New England). I ended up putting a heating coil on a relay and controlled by Octoprint to keep the enclosure temp ~25c. Also, with PLA, I print with a bed temp of 63-65c, which helps a lot. Keep an eye on the finish of the base of your model after you've pulled it up. For me, 65c gives the first layer a sharp edge around the base from the added flow. 

I printed a multipart (full size) Viking helm on MyMiniFactory where the quarters of the helm had to be glued and have no gaps. The warpage I had didn't kill the print, but there was a LOT of filing to get the curved parts straight enough to be glued. That was before I figured out that warpage was an issue, and that it's worse on models that are both longer and taller.

Now that I think about it, the layer shifts may be a direct result of the warping, since the model is moving in relation to where the print head thinks it should be. I'd be willing to bet you a cup of coffee that if you fix the warping, the shifts go away...

Hope this helps.

Erik

Posted : 04/06/2020 4:34 pm
ajisis
(@ajisis)
Eminent Member

Having similar problems.  I think the warping is the main problem.  Once that starts, the part may become detached from the bed, and moves, leading to what looks like a shift.

My observations so far:

I use the textured powder coated metal plate to print on, and the adhesion is much less than with the old MK2 bed, where I used a Buildtak layer over the standard polyimide.  Thorough cleaning of the plate with a scotchbrite pad in hot water and pure detergent ( no scent or coloring ) helps a lot.  Dont use IPA or acetone, they leave an oil film no matter what you do.  Once clean, avoid touching the bed with fingers !

Raise the bed temp about 5-10 deg above normal, eg 70 for PLA rather than 60.  Dont change the bed temp during the print, else it will contract and release the part.

Use a brim, around 4 loops wide. This prevents airflow lifting the corners.

Leave the model fan off for as high as you can go, even all the way on a model with thick sections.  The fan is only needed to aid cooling on thin sections and overhangs.  The newer fan on the Mk2.5 is too strong, and cools the bed and part when it comes on, leading to thermal gradients and loss of adhesion. I set the fan to 30-50% of full power, even when printing thin walls.

This post was modified 2 months ago by ajisis
Posted : 06/08/2020 1:18 am
matt.m5
(@matt-m5)
Active Member

I fixed my problem completely. The warping and shifting were not linked...completely separate issues.

Warping: The warping was due to the printing environment. Where I have my printer setup, in the basement, there was too much a temperature difference between the first layer and the upper layers - this resulted in the top layers "pulling" the bottom layers up. The basement is only 65-75F. To solve this issue I created a wood+acrylic enclosure and it solved my issue completely. Ideal environment temp to print at is ~84F. If you're experiencing warping then it's most likely you're environment.

Shifting: I checked my print settings and I had been printing in "silent" mode, which many people have reported causes significant issues (layer shifting). I switched it to "normal" mode and I have not had an issue since!

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Posted : 06/08/2020 4:17 am
ajisis
(@ajisis)
Eminent Member

I too have recently switched to "high power" mode, and it does seem to have stopped the layer shifts - others have also reported that.  Still would love to know why.  I did hundreds of prints with the Mk2 version in 'silent' mode, before upgrading to MK2.5S, and never had a problem.

But I have also had what looked like a layer shift, and it was because the part became warped and  detached from the bed during print.  Totally different cause of shift, but can look similar at first glance.

Good that you fixed the problem with environment temp.  Not my issue, my office is at more like 25 degC minimum, and still get warping unless I get the bed adhesion right.   

Posted : 06/08/2020 6:19 am
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