TheBum
Posts: 32
Joined: Fri May 18, 2018 10:13 pm

Re: Pits in layers

Thu Jun 07, 2018 3:29 pm

dkightley wrote:
Thu Jun 07, 2018 1:28 pm
arti has made, to me, a very valid suggestion that has....so far...fallen on deaf ears!!!
Probably because his response was so terse that only an expert would understand what he was alluding to.

I guess one way to test would be to change the layer start point setting so that the layers all start at the same point. If your theory is correct, then the pitting should be in a vertical line with those settings, correct?

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dkightley
Posts: 1539
Joined: Tue Mar 10, 2015 3:09 pm

Re: Pits in layers

Thu Jun 07, 2018 3:35 pm

I guess one way to test would be to change the layer start point setting so that the layers all start at the same point. If your theory is correct, then the pitting should be in a vertical line with those settings, correct?
No!. I did advise what to do.....
You will need to revert to these previous settings and reprint the part....and observe what is happening. Is the "gap" in printing happening at the start or the end of the extrusion path around the perimeter???
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

arhi
Posts: 321
Joined: Thu Oct 06, 2016 4:13 pm

Re: Pits in layers

Thu Jun 07, 2018 3:45 pm

TheBum wrote: Probably because his response was so terse that only an expert would understand what he was alluding to.
I listed the 2 settings that are responsible for the "pits". One is responsible for the missing extrusion at the beginning of the "line" and the other is responsible for the missing extrusion at the end of the "line".

For start turn them both OFF and see what you get, then understand how they work (search forum, google, ask question in forum..) and then tweak to what suits your printer.

The settings as is is probbly some default for the bowden extruder allowing for long time to relieve the pressure.. but both parameters are affecting print in visually similar way, both parameters are on the FIRST TAB of your settings so if I write "coasting, wipe" I assume you know how the first tab of your settings looks like and that those 2 settings on the first tab are responsible for the missing extrusion on begin/end of the line... Here, now I put it in "more words" maybe it's more helpful..
gcodestat integrates with Simplify3D and allow you to
Calculate print time accurately (acceleration, max speed, junction deviation all taken into consideration)
Embed M117 codes into G-Code
Upload your G-Code directly to Octoprint
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TheBum
Posts: 32
Joined: Fri May 18, 2018 10:13 pm

Re: Pits in layers

Thu Jun 07, 2018 3:54 pm

dkightley wrote:
Thu Jun 07, 2018 3:35 pm
No!. I did advise what to do.....
Yes, I saw that, but wouldn't it be easier to see if the layers all started at the same x-y position? I'm not saying the pits would be vertical, but that they would appear horizontally in the same x-y area of the print. How is that any different than sitting there and trying to watch it in random x-y positions?

TheBum
Posts: 32
Joined: Fri May 18, 2018 10:13 pm

Re: Pits in layers

Thu Jun 07, 2018 4:25 pm

Could the extrusion width being only 0.42mm for a 0.4mm nozzle cause this? That was the value in the FFF file I got for this printer. It seems to me that using a 1.10 extrusion factor would be the same as a 0.462 extrusion width (0.42 x 1.1) from the standpoint of how much plastic is extruded. The default extrusion width in S3D is 1.2 times the nozzle width, or 0.48mm in this case.

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dkightley
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Re: Pits in layers

Thu Jun 07, 2018 6:39 pm

I've made a suggestion.....you clearly for some reason do not think my suggestion is worth following. I therefore will not offer you any more advice.

Good luck with your efforts.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

TheBum
Posts: 32
Joined: Fri May 18, 2018 10:13 pm

Re: Pits in layers

Fri Jun 08, 2018 11:41 am

FWIW, I watched several layers on the same print and the peripheral lines all started in a corner, which makes sense for objects with flat faces bounded by sharp corners. Since the pits were previously distributed across the largest face, I'd say that probably rules it out being a lead-in or lead-out extrusion issue.

Changing the multiplier back to 1.0 and the extrusion width to 0.46 gave me similarly smooth results to a multiplier of 1.1 and an extrusion width of 0.42, as expected.

TheBum
Posts: 32
Joined: Fri May 18, 2018 10:13 pm

Re: Pits in layers

Thu Jun 14, 2018 10:57 am

An extrusion width of 0.48 (recommended value in the software) has eliminated all pits except a very few barely noticeable ones that I believe are near the beginning of extrusion lines. I have enabled wipe with the default length of 5mm to see if it gets rid of them. The first print didn't have any, but it also didn't have many layers; I'll have to keep testing on taller models.

I did not enable coast because I'm not seeing any blobs.

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