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Ferdinand
(@ferdinand)
Active Member
Bumps on vertical walls

Hello everyone!

I'm printing some boxes, and noticed that the prints come out with bumps on the walls (a.k.a. vertical shells). Please see the attached picture.
The printer is an MK2/S, its firmware is the latest version(3.1.0), and it's well calibrated. It is fitted with an Olsson Ruby nozzle, 0.4mm.

I tried to troubleshoot the problem:
- changed the extrusion multiplier between 0.97 and 1.03 - my extruder outputs 97mm out of 100mm filament;
- changed the filament diameter between 1.75 and 1.735mm (measured the filament over 1m length, for an average diameter of 1.735mm);
- reduced the printing temperature to 200deg Celsius in 5 deg decrements
- google, and search the forum for a similar post.

Nothing worked. While selected different "Seam position" options, I observed that the bumps show up according to the selection:
- close-by, if the "Seam position" is set on "Nearby"
- all over the walls, if the "Seam position" is set on "Random"
- aligned, if the "Seam position" is set to "Aligned",
which led me to conclude that the bumps happen at the seams. I attached the gcode file for examination.

Please help!

Thank you for your consideration.

Ferdinand

Posted : 29/01/2018 9:06 pm
Tinkerwest
(@tinkerwest)
Trusted Member
Re: Bumps on vertical walls

I'm afraid the artifacts are most likely an outgrowth of the design. Take a look at your gcode, most likely your walls bumping into each other leaving no room for the filament and thus the bump. Possible things to try add inside fillets this will provide some space, try less perimeters or make the walls thicker. Hope this helps good luck.

Posted : 30/01/2018 7:01 am
alexander.s27
(@alexander-s27)
Estimable Member
Re: Bumps on vertical walls


I'm afraid the artifacts are most likely an outgrowth of the design. Take a look at your gcode, most likely your walls bumping into each other leaving no room for the filament and thus the bump. Possible things to try add inside fillets this will provide some space, try less perimeters or make the walls thicker. Hope this helps good luck.

Either this and maybe that could be perimeter start points.
Using S3d you could specify a point where the start point should be...

Posted : 30/01/2018 8:36 am
Tinkerwest
(@tinkerwest)
Trusted Member
Re: Bumps on vertical walls

Yes, it could be a retraction scar. Slic3r also has a option to set it to random or a position. By default it's on nearest.

Posted : 30/01/2018 2:14 pm
Ferdinand
(@ferdinand)
Active Member
Topic starter answered:
Re: Bumps on vertical walls

Thank you for your replies! Will try your suggestions. I do know those bump are at the seams: if I select "Random" as Seam position (under Print Settings -> Advanced) the bumps take place randomly on the surface. Less noticeable, however, the faces have blemishes.

What is very annoying is that I printed many boxes before the latest firmware upgrade and nozzle change. All came out beautifully. This happened all of a sudden, and I don't know where is the faulty setting. 😕
I will post the solution to this problem once I find it.

Thanks again! 🙂

Posted : 03/02/2018 4:03 am
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