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Layer shifting?  

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flo
 flo
(@flo)
Active Member
Layer shifting?

I've been trying to print a small TPU tube for some time now and the upper layers of it always come out weird. I've had this problem before but could fix it by lowering the print speed. After transportation, the issue started again but could not be fixed even with a print speed of 10mm/s.

In the picture below you can see a few failed attempts with changing all sorts of settings (temp, speed, jerk, etc.). The best one was the second from the right (with very slow print settings) but even then, the upper layers came out wacky. The rightmost tube had been printed before the transportation with higher printing speeds (15-20 mm/s I think) and it came out fine.

tubes

I already ran a self test and a calibration, but it didn't help. I read the article on layer shifting but I'm not sure if this is the problem. Also, I couldn't try the solutions listed there because the MK3 belongs to the university that I'm studying at and I have limited access.

What do you guys think, could be the problem here?

Napsal : 27/03/2021 10:26 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Layer shifting?

this looks like movement of the part being printed, 
can you use braces to stabilise the parts during printing. 

I have read about someone using hot melt glue and bamboo stakes, tooth picks, coffee stirrers scrap prints or whatever is to hand... 

these will peel off easily when the model is finished. 
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Napsal : 27/03/2021 1:48 pm
towlerg
(@towlerg)
Noble Member
RE: Layer shifting?

@joantabb

Are you using a brim, if not definitely do so, or if that doesn't give enough stability, what about a moose ear?

Or maybe add a webs that you cut off, perhaps too much hassle? Or join short lengths together?

Edit. how about internal support, if it doesn't affect flow too much.

This post was modified před 4 years by towlerg
Napsal : 28/03/2021 11:50 am
FoxRun3D
(@foxrun3d)
Famed Member
RE: Layer shifting?

I’m with Joan, this looks as if the whole model is wobbling, at larger heights, not surprising if it’s TPU. One idea is to add sacrificial supports to the model, for example, four “fins” extending from the base to the top that you can later remove.

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Napsal : 28/03/2021 12:24 pm
Peter M
(@peter-m)
Noble Member
RE: Layer shifting?

After transport  of a 3d printer, do a z-calibration.

High models,

use a big brim,

print a few models at the same time, and make a bridge between the models so it is one big model,

or make smaller model nest to the printed model, and attach them together.

or print part of model and pause printing, hot glue a piece of wood to model and bed.(less printing time).

Keep speed high!

This post was modified před 4 years by Peter M
Napsal : 28/03/2021 1:21 pm
flo
 flo
(@flo)
Active Member
Topic starter answered:
RE: Layer shifting?

@joantabb

Tanks for your input Joan, and yes there is definitely movement when printing the part, but it wasn't a problem before, that's what's weird to me...

Unfortunately your idea of using braces may be too complicated for my use case. We want to use this print in a workshop for people who are completely new to 3D printing and I think applying braces mid-print would be too much to ask.

Napsal : 28/03/2021 3:49 pm
flo
 flo
(@flo)
Active Member
Topic starter answered:
RE: Layer shifting?

@towlerg

Hi thanks for your ideas! I think internal support may be possible, I'll see what I can do.

Napsal : 28/03/2021 3:51 pm
flo
 flo
(@flo)
Active Member
Topic starter answered:
RE: Layer shifting?

@fuchsr

Hi fuchsr, thanks for your input! As this print is going to be used in a workshop with 3D printing newbies, I think removing supports may be a bit too much for them. But I might try it anyways, maybe it's not that bad 🤔 

Napsal : 28/03/2021 3:56 pm
flo
 flo
(@flo)
Active Member
Topic starter answered:
RE: Layer shifting?

@peter-m

Hey peter thanks for your suggestions. I think I will try a bigger brim, this could work and may not be too annoying to remove.

Napsal : 28/03/2021 3:58 pm
towlerg
(@towlerg)
Noble Member
RE: Layer shifting?

@flo

Just a guess but I don't think a brim will help (although it couldn't do any harm) because it appears that as the part gets taller it's starting to wobble. Brim really only helps if that part is becoming detached from the bed.

Napsal : 28/03/2021 11:34 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Layer shifting?

@towlerg

Agreed. The brim is unlikely to mitigate movement at the top. You’d probably be fine with something like PLA or PETG here but TPU is too elastic. 

@flo

Does it have to be TPU?

Maybe you want to reconsider using this particular model for a beginners workshop... A lot of cursing is not the best entry point into a new hobby / profession. Just saying... 😇. 

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Napsal : 28/03/2021 11:44 pm
flo
 flo
(@flo)
Active Member
Topic starter answered:
RE: Layer shifting?

@fuchsr @towlerg

Yeaaa, you're probably right, but I realized that I stop using a brim for some reason, so I want to try that again.

@fuchsr

The thing with the workshop is that the 3D-printing part is just a short segment of it, which is supposed to showcase how additive manufacturing of spare parts can work on-site. And the tube is one of the two parts we can have participants replace at our small demonstrator. So yeah... Unfortunately it has to be TPU 😑

If it ends up not working, we still have that one PLA part that works fine, but it would just be too cool to not try and print a functioning tube for an air compressor 😀 

 

Napsal : 29/03/2021 7:35 am
towlerg
(@towlerg)
Noble Member
RE: Layer shifting?

@flo

IIWY I'd go for internal support. It may nor need to be a full diameter. Also, perhaps print the walls thicker.

Napsal : 29/03/2021 9:57 am
cwbullet
(@cwbullet)
Member
RE: Layer shifting?

@fuchsr

A brim by itself may not work well.  Add a brim with external supports that are removable.  

--------------------
Chuck H
3D Printer Review Blog

Napsal : 29/03/2021 1:29 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Layer shifting?

@cwbullet

No argument from me. This is what I suggested with sacrificial supports (eg 4 fins on the outside)

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Napsal : 29/03/2021 2:23 pm
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