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Help with PLA print  

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Ligyron
(@ligyron)
Active Member
Help with PLA print

Hello, I am using an i3 MK3S+ and have not had any issues.  My last print, I had the following issue.  Although it was not the bottom layer against the build plate, it was still a "bottom" layer as you can see from the attached picture.  I don't know if there is a correct term to describe the filament not adhering to the adjacent layer and coming away in strings.  I was using Prusament PLA. 

The remainder of the print came out fine, it was just that one layer.

I would appreciate any insight or advice.

 

Regards,

Nick

Posted : 04/11/2022 2:22 pm
Robin
(@robin)
Noble Member
RE: Help with PLA print

Might be that you try to print in thin air? Can you post the zipped project file from slicer?

If at first you don't succeed, skydiving is not for you.
Find out why this is pinned in the general section!

Posted : 04/11/2022 4:05 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Help with PLA print

Possibly stupid question, somewhat difficult to tell from photos, but is the surface you are showing the one that was facing downward toward the build plate at the time of printing?

If so, there's a lot of bridging to consider.

Posted : 04/11/2022 4:57 pm
Ligyron
(@ligyron)
Active Member
Topic starter answered:
RE: Help with PLA print

You are correct, it is printing in "thin air".  I just looked at it on Prusa slicer.

I selected bridging everywhere.  How do I get that area to be supported?  It is a convex surface, so I thought it made more sense to print it with the flat side down, Base_support_V2_0.2mm_PLA_MK3S_4h58m.gcode

This is the sliced gcode file.

Posted : 04/11/2022 6:42 pm
Robin
(@robin)
Noble Member
RE: Help with PLA print

Post the zipped project file. 

If at first you don't succeed, skydiving is not for you.
Find out why this is pinned in the general section!

Posted : 04/11/2022 7:46 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Help with PLA print

The Prusa is very good at bridging, in general, but it looks like your model has areas that simply will not bridge.

I am also assuming that this model is intended to have it's visible 'good side' on the top, as printed, thus it will be a good candidate for the 'greasy side down' approach, where the underside will not be subject to visible inspection.

I would use break-away supports, auto generated, build plate only, with a liberal contact Z distance.

Posted : 04/11/2022 8:01 pm
Ligyron
(@ligyron)
Active Member
Topic starter answered:
RE: Help with PLA print

Here is the stl file, zipped.Base_support_V2.stl

Posted : 04/11/2022 8:07 pm
jsw
 jsw
(@jsw)
Famed Member
RE:

Here is the bottom view when build-plate supports are enabled.  Note that the 'sane' bridged areas are bridged in this one as well.

The supports can then be broken off after printing, and it will leave a blemished 'greasy side', but not nearly as ugly as with the failed bridging.

 

Posted : 04/11/2022 8:18 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Help with PLA print

BY default Prusaslicer will try to bridge those areas. You can force it to use supports instead by unticking Print Settings→Support material→Options for support material and raft→Don't support bridges. However, don't expect anything close to the usual first layer quality as the line is still being laid down in thin air (how much, you can control with Top contact Z distance, I suggest 0.25mm), or the supports would be fused to the model.

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

Posted : 04/11/2022 9:17 pm
Ligyron
(@ligyron)
Active Member
Topic starter answered:
RE: Help with PLA print

Thank you very much all for you help.  I will try your advice.

 

Regards,

Nick

 

Posted : 05/11/2022 1:06 am
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