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First top infill layer problem  

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NM
 NM
(@nm)
Active Member
First top infill layer problem

The problem is such that the first top solid layer prints really bad, pics are attached.

The first top layer is printed on top of the infill, which has larger holes in it when less infill % is set. These segments can be considered as short bridges, but they are not treated as such, as the print speed does not seem to decrease when printing the first solid infill layer over the infill.

My guess is that, as a consequence, the limits of the first solid infill layer suffer from problems: sometimes the plastic dips into the holes, but others it climbs up a little bit, interfering with the printing of the subsequent layers.

The problem may get worse in time, causing the print to fail by crash detection.

The worst is on the limits of the first layers, which does not even count as a bridge, but as a protruding loop, as you can see in the pictures. Other parts of the print are also suffering in slightly different ways, as it can be seen in all the pictures.

Sometimes a "contour" of the first layer is printed. You can see one of those in pictures 1 and 4, but none in picture 5, and some in the honeycomb print first layer.

I have tried to alleviate this issue by reducing the solid infill layer's print speed up to 50 mm/s, and by decreasing the nozzle temperature to 200°C. Increasing the infill % also helps. I have not messed with the K value.

It is also possible that there are other underlying causes to this issue, but I am not able to figure out which, if any. Can under-extrusion be related?

I believe a solution would be to print extra area of the first solid layers, so that all of the segments can stick to the infill walls below, and form a proper bridge.

Perhaps the solution is simpler or the problem is another, but, inspite of moderate searching, I have not been able to find a solution.

I hope you can help! Thanks in advance <3

Printer: i3 MK3
Filament: Prusa PLA
Settings: 0.20 FAST with 10%-15% infill (later modified as described above).

Edit: I have found someone with the same unsolved issue here: https://forum.simplify3d.com/viewtopic.php?t=4759

Opublikowany : 30/10/2018 11:37 pm
NM
 NM
(@nm)
Active Member
Topic starter answered:
Re: First top layer problem

the honeycomb pictures were missing from the first post

Opublikowany : 30/10/2018 11:39 pm
bobstro
(@bobstro)
Illustrious Member
Re: First top layer problem

Have you tried adding interface layers with your infill.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Opublikowany : 30/10/2018 11:45 pm
NM
 NM
(@nm)
Active Member
Topic starter answered:
Re: First top infill layer problem

Nope, but I'm also not sure what it means.

I understand that interface layers are for external support material, but i guess that these solid infill layers are the support material for the layers above.

I can't find such a setting in Slic3r, could you explain how you would do this?

The problem would be mostly solved If I could get the printer to cover the infill squares (or hexagons) completely for the first solid infill layer.

Thank you for your reply.

Opublikowany : 31/10/2018 1:23 am
bobstro
(@bobstro)
Illustrious Member
Re: First top infill layer problem


[...] I understand that interface layers are for external support material, but i guess that these solid infill layers are the support material for the layers above.

Ah, I misinterpreted the pic. You're right, your problem is with infill.

Can you post a link to the part so it's easier to visualize what's going on? Usually I see a pattern like that for the bottom of a cutout where the surrounding areas will continue to build upwards. Is the layer with the partial surface supposed to be a solid layer?

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Opublikowany : 31/10/2018 2:04 am
NM
 NM
(@nm)
Active Member
Topic starter answered:
Re: First top infill layer problem

Sure, sorry for the delay.

Here are more pics and a https://www.thingiverse.com/thing:3186607 .

I have found someone with the same unsolved issue here: https://forum.simplify3d.com/viewtopic.php?t=4759

Opublikowany : 01/11/2018 5:49 pm
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