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Top layer not closing

Posted: Fri Jul 14, 2017 4:48 pm
by jponitz
My infill layers are frequently not overlapping with the perimeters. This is most prevalent on the top layers, which results in some ugly flat top faces (see photo). I've tried incrementally bumping up my Infill Overlap settings in MatterControl, as high as 1.0 mm (the suggested default is 0.25), and the simulated Layer View shows a lot of overlap, but the actual prints do not. Any ideas?

For what it's worth, I recently made a bunch of upgrades to my old Orion: new carriages, ball joint arms, HE280 hot end, and EZRstruder. Print quality is otherwise pretty good since the upgrade, but I don't remember having this issue before.

Re: Top layer not closing

Posted: Sat Jul 15, 2017 2:07 pm
by Tincho85
Is it because of the camera lens or the centers of the tapered cube are inflated?

Re: Top layer not closing

Posted: Sat Jul 15, 2017 4:33 pm
by jponitz
I don't think the corners are actually inflated--the overall geometry and print quality are pretty good. I've printed a variety of shapes, and the flat tops are never quite closed.

Re: Top layer not closing

Posted: Sun Jul 16, 2017 11:22 am
by geneb
You don't have enough top layers. You want 3 minimum.

g.

Re: Top layer not closing

Posted: Sun Jul 16, 2017 7:46 pm
by joe
I usually try for 6 layers on a flat surface and up 12 for a curved top finish

Re: Top layer not closing

Posted: Mon Jul 17, 2017 9:30 am
by knabo
It looks like some of the lines overlap the perimeters and some don't. Unfortunately there is not always a simple answer. Due to the randomness of the end lines I might suggest you try changing the temperature you are printing this filament.

Does your first layer look the same way?

What type of filament is this? If it is ABS, the model might be too cold for proper adhesion.

Re: Top layer not closing

Posted: Mon Jul 17, 2017 3:15 pm
by jponitz
Thanks geneb and joe for the suggestions on layers--I'm currently printing 5 top layers, so I don't think that's the issue, but will bump it up.

Thanks knabo for the temperature idea--I'm printing PLA at 200, I'll play around with that. The first layer looks similar, but a little better, because it gets a little more smooshed against the build plate. The intermediate infill layers are often not connecting either.

Re: Top layer not closing

Posted: Mon Jul 17, 2017 6:54 pm
by Xenocrates
that sounds like either too high a layer height for the nozzle size, or too little extrusion over all. But the sides on the tapered cube don't look starved or too tall either. Perhaps it's an issue with the track width settings, or overlap?

Re: Top layer not closing

Posted: Mon Jul 17, 2017 7:22 pm
by Tincho85
Do you get the same results with a different slicer?

Re: Top layer not closing

Posted: Tue Jul 18, 2017 6:46 pm
by Qdeathstar
Hi.

What is your nozzle size and extrusion width set to? It looks like those top lines are pretty fat...