How do I get rid of the pimples on my prints?
November 27, 2012 08:21PM
Sometimes I get more sometimes I get less but I always end up with these bumps on the surface of my prints at the end of perimeters. If not for these bumps my prints would turn out great. I'm printing on a prusa mendel, with J-Head MK IV-B hotend, and ultimachine PLA. I'm printing perimeters at 50mm/s, 1.5mm retraction @ 20mm/s. Any ideas?
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Re: How do I get rid of the pimples on my prints?
November 27, 2012 08:33PM
uncheck random starting point in slic3r.
Re: How do I get rid of the pimples on my prints?
November 27, 2012 10:32PM
I'm currently using 0.7.2b since the current version ignores my solidfill layer number and perimeter number parameters. This version does not have that option. Also I've found the blobbing to be worse in the newest version.

Also, wouldn't that just cause them all to be on the same line? I'd still have the bumps wouldn't I?
Re: How do I get rid of the pimples on my prints?
November 27, 2012 10:41PM
1.5mm is a pretty big retraction, try and make it as fast as possible.
I run with a 0.8mm retraction at 25mm/s with 30mm/s perimeters with no blobs.
(My belts are rather stretchy)
Try and see how fast your retractions can go, and how small you can get away with.
Re: How do I get rid of the pimples on my prints?
November 27, 2012 11:11PM
Reduce the extrusion ratio from 1.0 to about .985.
Also get rid of any retraction if you have any.
Re: How do I get rid of the pimples on my prints?
November 28, 2012 08:52AM
If your extrusion is calibrated leave it alone, there should only be a 'fudge' (Swell) factor for ABS.
Your retraction is very long, aim anywhere below 1mm and as fast as your extruder reliably allows. If your retraction needs to be that long to prevent ooze, then you are probably running your extruder marginally too hot.
Re: How do I get rid of the pimples on my prints?
November 28, 2012 01:54PM
I'll try reducing temp and then reducing and quickening my retraction.
Re: How do I get rid of the pimples on my prints?
November 29, 2012 03:58AM
Nice print! Increasing z speed and acceleration can also help. I got terrible blobbing like that on my first printer because I had to run the z very slow due to binding.


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Re: How do I get rid of the pimples on my prints?
November 29, 2012 09:28AM
I think I got the same problem, please let us know if suggestions works. I will try to reduce retraction as well.

http://www.3byazici.com/2012/11/3d-printer-ile-master-yoda.html


[www.3byazici.com]
[3dprintertr.com]
Re: How do I get rid of the pimples on my prints?
November 30, 2012 04:33AM
I am doing 1mm retract @ 15mm/s and my results look similar. I expect disabling random start point to be a very good idea as he would stop skipping around randomly.
Re: How do I get rid of the pimples on my prints?
December 05, 2012 04:43AM
Update: I've disabled random start point, disabled "additional perimeters" and selected to do only one perimeter. Its looking much better.
The pimples have gone completely away after I reduced the layer height from 0.4 to 0.2. The only thing left are blobs whenever he needs to travel. I guess its due to oozing.

I can even enhance everything by doing faster travels. I can only guess but it feels like there is to much pressure on the filament. Maybe its to springy due to the head, therefore the retract isn't as effective as it should be.

Perimeters: 120mm/s
Infill: 150mm/s
Travel: 200mm/s
Retract 1.25mm @ 15 mm/s
Temp: 185 °C PLA

Edited 2 time(s). Last edit at 12/05/2012 06:08PM by DerKulturfolger.
Re: How do I get rid of the pimples on my prints?
December 08, 2012 06:02AM
Hi,

I am now doing 1.25 retract at 50mm/s and its really looking great. Another thing creating a better looking print was to use locking nuts to fasten the springs of the printbed. Those nuts kept undwinding themself leading to an unleveled printbed while printing.

Maybe you could give me/us an update on your progress?

Ingo
Re: How do I get rid of the pimples on my prints?
December 09, 2012 05:55PM
Been working a lot lately and haven't had too much time to play. I've been trying to slowly increase my retraction speed and it has been helping. I find I get fewer pimples when I use slic3r 0.7.2b rather than the newer versions, but I wish I could take advantage of some of the newer features. I still have not found a good calibration piece for this. I'll just start making parts and experimenting.
Re: How do I get rid of the pimples on my prints?
December 10, 2012 12:55AM
Slic3r 9.7 is causing pimples and spikes: [github.com]
Re: How do I get rid of the pimples on my prints?
December 10, 2012 09:58PM
Idolcrasher Wrote:
-------------------------------------------------------
> Slic3r 9.7 is causing pimples and spikes:
> [github.com]

Thanks for the Update!

I had thought 9.7 had fixed everything. But this week it has been doing psycho jobs on some of my .stl files. to the point I've been screening the gcode through the pronterface viewer before I commit the print.

angry smiley
Re: How do I get rid of the pimples on my prints?
December 10, 2012 10:14PM
I suggest trying Kisslicer as it produces much nicer Gcode then Slic3r and has a feature called wipe that stops almost all bumps and strings. Just be sure to have your retract as short and fast as possible.


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Re: How do I get rid of the pimples on my prints?
December 19, 2012 03:44AM
As an update slic3r 0.7.2b solved my pimple problem. I can print very clean outer perimeters, however I still have ooze problem to solve sad smiley
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