Hi All I seem to be having a problem nowadays in that my sparse infill tends to be very messy and the top layers always end up with holes in them. It seems the nozzle tends to accumulate a little plastic on it (away from the hole) and this then causes the plastic the nozzle to pick up previous threads laid in the next pass (not layer but when the nozzle swings back on the adjacent strand). I am not sure what changes I have made, but I do remember changing layer thickness from 0.35 to 0.33 and perimiter width over thickness ratio to 1.5 from 1.8 (to enable 2mm walls with an extra shell). I am currently running a bunch of tests and upping the temperature (PLA) to 205 seems to be giving better results, but not good enough. Is it better to have a nozzle tip that is a sharp point rather than a blunt point so that there is minimal opportunity for plastic to stich to the barrel and drag the newly laid stuff away? https://reprap.org/forum/read.php?1,92737,92737#msg-92737 Sat, 13 Jun 2026 01:42:28 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,92737,92889#msg-92889 https://reprap.org/forum/read.php?1,92737,92889#msg-92889
Won't Perimeter W/T only effect the perimeter paths? There's something similar under Fill, but i don't think it works exactly the same, since the skeinforge manual says to decrease the number if you get sparse infill.]]> Buback General Wed, 03 Aug 2011 16:03:33 -0400 https://reprap.org/forum/read.php?1,92737,92825#msg-92825 https://reprap.org/forum/read.php?1,92737,92825#msg-92825
I,ve also made a few tips that were wide and convex, and they didn't seem to drag either, but then again, all my stuff seems to be more the exception than the rule here :)]]> jcabrer General Wed, 03 Aug 2011 09:21:20 -0400 https://reprap.org/forum/read.php?1,92737,92790#msg-92790 https://reprap.org/forum/read.php?1,92737,92790#msg-92790
That is interesting. I will give it a try.

I guess the oil film is so thin that it will not affect the adhesiveness of the layers being put down.

I did run a test putting my Perimiter Width Over Thickness (ratio) - PWOT - up to 1.8 from 1.5 and that seems to have improved the surface.

As brnrd states, my infil tends to be very messy (30% 0.5mm nozzle 0.33 layer thickness) with very thin strings between the contact points where a strand contacts the layer below. At the contact points it seems to be a bit bigger.

Out on the lash tonight so will run some further tests tomorrow...]]> AgeingHippy General Wed, 03 Aug 2011 04:33:02 -0400 https://reprap.org/forum/read.php?1,92737,92781#msg-92781 https://reprap.org/forum/read.php?1,92737,92781#msg-92781
If plastic accumulates on the nozzle while it is extruding it generally means the flow rate is too high.

Interesting tip about using oil. I will give that a try.]]> nophead General Wed, 03 Aug 2011 02:50:13 -0400 https://reprap.org/forum/read.php?1,92737,92753#msg-92753 https://reprap.org/forum/read.php?1,92737,92753#msg-92753

A trick I use now is to lubricate the nozzle with oil on the outside. This makes it less likely to stick or stay sticking to the nozzle in any area.

if plastic crud accumulates on the outside of your nozzle, the plastic is like glue to other plastic, and will tear your build apart as the plastic will stick better to the hotter plastic on the nozzle.


With the nozzle heated, take a cotton cloth (no synthetics as they will melt) put some 3 in one oil on the cloth, and wipe away plastic crud, if anything remains, wire brush it or scrape it away with a screw driver. When finished, wipe down base of nozzle with oil.

This possibly is a reason that makerbot went with teflon coating on outside of there nozzles. as for nozzle designs, i think a flat bottom with a small surface area reduces drag and improves stringing issues.]]> jamesdanielv General Tue, 02 Aug 2011 19:36:59 -0400 https://reprap.org/forum/read.php?1,92737,92746#msg-92746 https://reprap.org/forum/read.php?1,92737,92746#msg-92746 brnrd General Tue, 02 Aug 2011 18:32:28 -0400 https://reprap.org/forum/read.php?1,92737,92739#msg-92739 https://reprap.org/forum/read.php?1,92737,92739#msg-92739
How about some nice closeup pictures of the problem print and nozzle to help troubleshoot.

I'm guessing you have too much filament. Do you have the same problem with sparse infill? (60% or less)]]> Andrew Diehl General Tue, 02 Aug 2011 16:29:01 -0400 https://reprap.org/forum/read.php?1,92737,92737#msg-92737 https://reprap.org/forum/read.php?1,92737,92737#msg-92737
I seem to be having a problem nowadays in that my sparse infill tends to be very messy and the top layers always end up with holes in them.

It seems the nozzle tends to accumulate a little plastic on it (away from the hole) and this then causes the plastic the nozzle to pick up previous threads laid in the next pass (not layer but when the nozzle swings back on the adjacent strand).

I am not sure what changes I have made, but I do remember changing layer thickness from 0.35 to 0.33 and perimiter width over thickness ratio to 1.5 from 1.8 (to enable 2mm walls with an extra shell).

I am currently running a bunch of tests and upping the temperature (PLA) to 205 seems to be giving better results, but not good enough.

Is it better to have a nozzle tip that is a sharp point rather than a blunt point so that there is minimal opportunity for plastic to stich to the barrel and drag the newly laid stuff away?]]> AgeingHippy General Tue, 02 Aug 2011 16:06:34 -0400