# How to improve density and eliminate gaps in a print?

**URL:** <https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309>\
**Category:** Filament\
**Created:** [November 1, 2013, 6:17pm UTC](https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309 "2013-11-01T18:17:26Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ndpmcintosh](https://avatars.discourse-cdn.com/v4/letter/n/958977/32.png) [@ndpmcintosh](https://forum.lulzbot.com/u/ndpmcintosh)\
**Post date:** [November 1, 2013, 6:17pm UTC](https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309/1 "2013-11-01T18:17:26Z")

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Hey all;

I am working on my first actual design-and-print project which is a cabinet replacement knob in ABS designed to take a #8 screw. The plan is to tap the hole but I may also just try a sheet metal screw directly. The basic shape is correct but the print always comes out with a gap somewhere in the exterior surface. I’ve attached a photo.

Also, what SLIC3R settings are best for trying to get as dense an infill as possible for the screw to be securely fastened?

Thanks,

Phil…

 ![Knob_with_hole_prototype.JPG](https://us1.discourse-cdn.com/flex020/uploads/lulzbot/original/1X/c8f63d181cc06b21d6b00c5ea1a3e1926b9880d9.jpeg)

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**Author:** ![gannon](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/gannon/32/10_2.png) [@gannon](https://forum.lulzbot.com/u/gannon)\
**Post date:** [November 1, 2013, 6:32pm UTC](https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309/2 "2013-11-01T18:32:28Z")

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What size nozzle do you have an what is your layer height? Looks like the filament didn’t stick on a layer and got dragged by the nozzle.  
I would try decreasing the layer height and trying again.

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**Author:** ![ndpmcintosh](https://avatars.discourse-cdn.com/v4/letter/n/958977/32.png) [@ndpmcintosh](https://forum.lulzbot.com/u/ndpmcintosh)\
**Post date:** [November 1, 2013, 8:04pm UTC](https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309/3 "2013-11-01T20:04:47Z")

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Thanks. Yes I decreased it and it improved. Nozzle size is .35. A little more tweaking there will probably get it. But, I am worried about the support around the hole. Is there a strategy for making the inside of an object fill in as fully as possible? 100% fill?

Phil…

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<div class="post-metadata">

**Author:** ![gannon](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/gannon/32/10_2.png) [@gannon](https://forum.lulzbot.com/u/gannon)\
**Post date:** [November 1, 2013, 8:31pm UTC](https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309/4 "2013-11-01T20:31:26Z")

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I would adjust the overlap between infill and perimeter, but this isn’t an option in slic3r as far as I know.  
You may be able to adjust the extrusion multiplier to fix the issue though.

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**Author:** ![bam](https://avatars.discourse-cdn.com/v4/letter/b/34f0e0/32.png) [@bam](https://forum.lulzbot.com/u/bam)\
**Post date:** [November 1, 2013, 9:42pm UTC](https://forum.lulzbot.com/t/how-to-improve-density-and-eliminate-gaps-in-a-print/309/5 "2013-11-01T21:42:13Z")

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> [@ndpmcintosh](#):
>
> Thanks. Yes I decreased it and it improved. Nozzle size is .35. A little more tweaking there will probably get it. But, I am worried about the support around the hole. Is there a strategy for making the inside of an object fill in as fully as possible? 100% fill?
> 
> Phil…

You can adjust the infill density in slicer, 90% is sufficient for most parts.

It looks like the problem is that not enough plastic is being extruded; the most common cause of this is bits of filament clogging a few of the teeth on the hobbed bolt. The clogged teeth won’t be able to grab the filament, so the extrusion gets thrown off by quite a bit.

I’d check and clean the teeth of the hobbed bolt in the extruder, and decrease your print speeds a bit if the problem comes back. That should keep the filament from stripping.

You can also print at higher speeds without stripping if you go up to a .5mm nozzle. You’ll lose a bit of resolution, but the increase in speed and reliability makes it our nozzle size of choice here at AOHQ

Hope this helps!  
-bam