Strange issue like partial shrinking of the wall on a print with 100% infill  

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

I think you are seeing the "buldge" effect that can occur when there are transitions between sparse infill, solid infill, gap fill and solid perimeters. This has been discussed in several other threads in depth. Start here.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

Thanks for the hint

I was aware of this thread but thought the "buldge" effect only appears at the transition from solid infill to sparse infill.

The strange thing is, in my file there are on all layers only internal and external perimeters. There is no transition of different infill types.

I will make a try with printing the external perimeter first or make the part a bit thicker. 2mm wall thickness was probably not the best choice as it's a bit more than 3 perimeters and a bit less than 4 perimeters.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

The uneven thickness of walls on layers where features appear elsewhere on the print (e.g. layers corresponding to those holes) seem to be where this shows up. Anything that causes a change in speed and flow seems to be a possible trigger. Sorry I can't suggest anything specific, but calibrating my extrusion multiplier and slowing down has yielded the best results for my prints.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

@fabi

I've doing working on a project lately that required ASA, I had a bit left on the roll so I decided to print your design and see how it turned out.

This is Prusament ASA Signal White

Printed with Prusa ASA default profile I made no attempt to tune the model or the print profile.

printed on a textured bed, no brim, no glue, no enclosure with 0.4 nozzle ( I know you used a 0.6), first layer 0.2 all other layers 0.3 2 perimeters.  print time 2hours  5min.

I think the result is acceptable, and certainly could be tuned if needed to produce a cleaner result.

My guess would have to be it has something to do with the 0.6 nozzle size, the speed of the print or the extrusion multiplier in conjuction with the 0.6 nozzle, I'm guessing, but your model is sound and very well done, the 2mm seems plenty strong for its intended use.

Good Luck, hope this helps.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

Posted by: @swiss_cheese

[...] My guess would have to be it has something to do with the 0.6 nozzle size, the speed of the print or the extrusion multiplier in conjuction with the 0.6 nozzle, I'm guessing, but your model is sound and very well done, the 2mm seems plenty strong for its intended use.

A larger nozzle is going to work with far less back-pressure, so should be able to keep a more consistent flow going with speed and directional changes, especially on larger prints. The wider extrusions also probably result in less sparse infill and use of gap fill on vertical walls, so walls are thicker and more consistent from top to bottom. This makes sense. 

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

Thanks a lot bobstro and swiss_cheese. Especially thanks for doing the testprints.

The print of swiss_cheese is looking great. That is what I'm used to achieve with the 0.4mm nozzle. In this print, I'm using the 0.6mm nozzle because of the higher robustness of the printed part and the higher print speed (I need several of this holders)

I am printing at the moment a test with external perimeters first und one with slower speed for all perimeters.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

I've not had good luck with "external perimeters first" the times I've tried it, it tends to almost look like is prints all the things you don't want to see on the outside of the print, e.g. retractions, detraction's, etc,, at least that was my experience the couple of times I tried it, of course its all relative to the model being printed.

what I was thinking after printing this one was, if your using a 0.6 nozzle with 2 perimeters you may want to match the wall thickness to the width of 4 perimeters, or just step back to 1 perimeter with gap fill, as it stands right now your internal perimeters are overlapping with a 2mm wall at 0.6 nozzle diameter. it printed just right with 0.4 nozzle.

once again I'm just guessing, I couldn't put a 0.6 nozzle in for this test because of other work I'm doing with 0.4 now.

Good luck to you I know you'll work it out

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

@fabi

I was just sitting here talking on the phone, and it occurred to me to do an X Y compensation of 0.2 in slicer on your model, I tried it and it gave perfect 2 perimeter results in slicer using the 0.6 nozzle, if your model has a tolerance of 0.4 between it and the radio, you may want to consider trying this, it seems as though it will get rid of the unsightly overlapping issue.

Just a thought,

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

Hi all

Thanks for the suggestions. Here are the results of my tests. It's not exactly the same part as in the OP but the wall thickness is also 2mm and the visible effect is the same.

PS original print settings 0.3mm QUALITY:

Same settings but speed for all perimeters reduced to 20 mm/s. The image looks a bit better but in reality, you almost can't see any difference:

Original settings but print external perimeters first. Same experience as swiss_cheese, the "bulgde" effect is less visible but you have a lot of other nasty effects:

Then I thickened the wall of the part to 2.41mm what's the recommendation of PS for 4 perimeters with a 0.6mm nozzle. And the result is quite acceptable in my eyes. At least more than enough for these parts as the function is much more important than the look:

So, my personal summary: try to design thin walls that way, that PS can fill them with full perimeter lines.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

The last one dose look the best, and that's been my experience as well. also slowing it down would improve the look if needed.

thanks for showing us your developing results and your conclusion, I think it helps people following the post.

I never like it when OP drops off the face of the earth with no closure.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

2mm walls with the 0.6mm nozzle do not come out well. Is there a workaround other than changing the wall thickness? Or better results with Cura?

Tonitom

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

Ok, with the option detect thin walls you get a smooth surface.

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

@tonitom

2mm walls with the 0.6mm nozzle do not come out well. Is there a workaround other than changing the wall thickness?

Change the nozzle size.

The underlying problem is that the default extrusion width for a 0.6mm nozzle (0.675 iIrc) does not permit an adjustable fill layer between the two exterior perimeters:

If the outer perimeters are correctly placed they do not quite touch internally but there is not room for a filler strand to connect them...  Something has to give.

For an accurate wall with a 0.6mm nozzle the minimum thickness is in the region of 3.2mm but it will be close from 2.7mm upwards.

If you want an accurate 2mm thick wall even a 0.4mm nozzle is a little too big 'though it will be close.  A 0.35mm nozzle would do it...

Cheerio,

RE: Strange issue like partial shrinking of the wall on a print with 100% infill

@diem

Thanks for the information, I will take that into consideration in the future.