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Gaps between perimeter shells?

Posted: Sun Feb 10, 2019 6:39 am
by Mike600
Anyone knows why there are gaps between the perimeter shells?
The outside perimeters look OK, there are no gaps, this seems to be happening only for holes. Bigger holes seem to be OK, smaller ones are the problem.
I don't think it's extrusion multiplier because the solid infill looks OK, it does not look under extruded.

Here's a pic with the problem:
Image

Any ideas?
Thanks!

Re: Gaps between perimeter shells?

Posted: Sun Feb 10, 2019 7:58 am
by tenaja

Re: Gaps between perimeter shells?

Posted: Sun Feb 10, 2019 10:08 am
by Mike600
I don't think that's it... I have 3 perimeters, and as you can see the infill joins with the 3'rd perimeter. The problem is that the perimeters don't touch!

Also, as I said, this only happens on small holes, the outer perimeter is fine

Re: Gaps between perimeter shells?

Posted: Sun Feb 10, 2019 5:03 pm
by horst.w
What the Print Preview shows and you can reproduce this issue?

If possible, attache the stl-file here, so anybody can test it on his installation.

horst.w
GER

Re: Gaps between perimeter shells?

Posted: Mon Feb 11, 2019 2:08 am
by Mike600
The preview does not show anything unusual... I attached the FFF profile, and the STL I was printing at the time.

My printer is custom made, cartesian, bowden, 400x400x400mm, with a Duet WiFi board
Simplify3D version 4.1.1

Here is a screen shot of the preview:
Screenshot from 2019-02-11 02-00-39.png

Re: Gaps between perimeter shells?

Posted: Mon Feb 11, 2019 6:54 am
by horst.w
Hi,
the print preview shows it fine for me, slicing the stl-file in my system and also after loading in your fff-profil.

I guess the reason is to look for in the unusual settings for PLA (220° print temperature, 140° bed temperature, relative settings for E-steps a.s.o) and the settings for retraction. 3.80 mm retraction is only to recomment for bowden extruders, direct extruders have round about 1 - 2 mm. The most inacceptable value is the restart with -0.40 mm. That pulls back the material from outgoing of the nozzle for a long time while the print head is running away normal. Cooling the PLA for only 30 points of 255 is like nothing. Your system will be over heated and the extrusion stops.
It seems the FFF values are overlaid with strange values or they are specials of the printer manufacturer.

H.

Re: Gaps between perimeter shells?

Posted: Mon Feb 11, 2019 7:24 am
by Mike600
The print bed is 60 degree. The 140 degree you saw is the nozzle. It first heats to 140 while the printer is probing the bed, when it's done probing, then it goes to 220. This is just to make the printer startup a little faster.

The 30 cooling, that's 30 percent (not points). I have a blower fan, if I set it too high (about 70% or more) the PLA gets delaminated and cracks very easily.
Also, in the Fan Overrides, I have "Increase fan speed for layers below 45 seconds", and "Maximum cooling fan speed 50%", also "Bridging fan speed override to 60%."
So cooling changes depending on the situation

I changed the Extra restart distance to -0.1, I will try it out with a smaller part.

Re: Gaps between perimeter shells?

Posted: Tue Feb 12, 2019 8:42 am
by Mike600
Just want to Thank You! it is working now.

I tested with some small parts, and it prints OK now