Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

New elephant foot and brim for thin objects too aggressive? #3949

Closed
Seikilos opened this issue Mar 29, 2020 · 10 comments
Closed

New elephant foot and brim for thin objects too aggressive? #3949

Seikilos opened this issue Mar 29, 2020 · 10 comments

Comments

@Seikilos
Copy link

Version

New issue since 2.2.0 win 64

Operating system type + version

Windows 64, 1903

3D printer brand / version + firmware version (if known)

Prusa I3 MK3S 3.8.0

Behavior

The slicer creates tool paths that seem to peel my prints from the print bed.

I noticed that having a brim and a skirt creates a tool path that rips the print from the bed.
Elephant Foot compensation might also be a problem (but I doubt that)
I attached a 3mf file where you can see the default behaviour

  • Slice the 3mf and look at the toolpath
  • The toolpath looks very strange and during print the toolpath gets so bad that the second layer has loose strands that get in the way of the printhead resulting ripping of the print or printing in air
  • Disabling skirt when brim is active seems to solve the issue

This behaviour is new to me as I have already used brim without any issues.

Project File (.3MF) where problem occurs

Toolpath elephant.zip

@bubnikv
Copy link
Collaborator

Maybe the elephant foot compensation is not a good idea for this kid of object and you should disable it?

@rtyr would you please try to print it? Thank you.

@bubnikv bubnikv changed the title Prusa Slicer 2.2 now creates toolpaths destroying prints New elephant foot and brim for thin objects too aggressive? Mar 29, 2020
@Seikilos
Copy link
Author

Seikilos commented Mar 29, 2020

Tried it. Elephant Foot has no effect. The weird skirt path seems to be the problem.

@bubnikv
Copy link
Collaborator

: The toolpath looks very strange and during print the toolpath gets so bad that the second layer has loose strands that get in the way of the printhead resulting ripping of the print or printing in air

I see, I did not understand.

second layer has loose strands

Second layer of what? The skirt or the brim?

@Seikilos
Copy link
Author

Seikilos commented Mar 29, 2020

Ok, probably ignore my "second layer" guess :/

It was hard to see. I think the problem is how the slicer creates the skirt path through the brim:
skirt+brim

I am very sure that this is a bug because I clearly remember, that the skirt was always created on the outer perimeter of the brim before.

Now the slicer creates a path where the skirt just plows through the brim. Previously the brim was a continuous path but now the skirt interrupts it. While it does not directly crosses the path, it moves through a location where many extruded lines end (marked in red). This sometimes cause to rip the layer of the bed or create inconsistencies.

I cleaned the bed with soap and printed with PETG, so I do not assume adhesion is the problem there because usually after a soap cleaning I barely can get PETG off (I know, windex, etc)

By looking again at the first layer I am also no longer sure that elephant foot compensation has no effect there as well. It seems that in addition to the skirt+brim chaos the printed object is shrunken and does not touch the brim any more.

I think there are multiple effects in combination that cause the issue.

@bubnikv
Copy link
Collaborator

bubnikv commented Mar 29, 2020 via email

@lukasmatena
Copy link
Collaborator

I am very sure that this is a bug because I clearly remember, that the skirt was always created on the outer perimeter of the brim before.

It is not a bug. The previous behaviour was in fact inconsistent with settings (see #724). The new behaviour solves two issues for people using skirt as draft shield:

  1. they want it close to the object - and that was not possible if the object had brim
  2. the tall skirt easily detaches from the bed - possibility to connect it with brim helps.

If you want the skirt further from the object, increase skirt distance in Print Settings.

However, maybe the current solution is not the best idea. Maybe the brim lines should be printed the way they were (i.e., continuously) and the skirt lines should be trimmed. Currently it's the other way round - brim is trimmed by skirt.

@Seikilos
Copy link
Author

I am very sure that this is a bug because I clearly remember, that the skirt was always created on the outer perimeter of the brim before.

It is not a bug. The previous behaviour was in fact inconsistent with settings (see #724). The new behaviour solves two issues for people using skirt as draft shield:

1. they want it close to the object - and that was not possible if the object had brim

2. the tall skirt easily detaches from the bed - possibility to connect it with brim helps.

If you want the skirt further from the object, increase skirt distance in Print Settings.

However, maybe the current solution is not the best idea. Maybe the brim lines should be printed the way they were (i.e., continuously) and the skirt lines should be trimmed. Currently it's the other way round - brim is trimmed by skirt.

So it's a feature (albeit a not yet optimal one) and not a bug? :)
This would then imply that the elephant foot itself would be the issue then?

@rtyr
Copy link
Collaborator

Test results looks OK to me. (PLA - based on provided 3MF).

3949

@bubnikv
Copy link
Collaborator

So it's a feature (albeit a not yet optimal one) and not a bug? :)
This would then imply that the elephant foot itself would be the issue then?

There are things that take some time to fine tune. We believe the feature works. Maybe one shoe will fit not all sizes.

Let's collect some feedback before doing a decision. Maybe you just need to increase squish against the print bed.

This seems to be quite a topic.
#3915
#3870
#3840

Also one customer asks for configurability of the gap
#3779

@lukasmatena
Copy link
Collaborator

lukasmatena commented Aug 12, 2021

Fixed in 2.4.0-alpha1: #3870 (comment)
Closing.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

4 participants