1st Wall of Test Cube is Too Thin?

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Gwhite
Posts: 234
Joined: Tue Jul 11, 2017 3:38 pm

1st Wall of Test Cube is Too Thin?

Post by Gwhite » Thu Sep 05, 2019 4:24 pm

I just switched from red eSun PLA+ filament to a new spool of "pine" green. I always run a single wall 20 mm calibration cube when I switch filaments to set my extrusion multiplier. The red test cube had the last 3 walls right at 0.40 mm (measured in the middle of each wall), with the first wall at 0.38 mm or so, which I figured was good enough.

The green filament wasn't too far off on the last 3 walls, but now the first wall is 0.36 mm thick in the center, and it's 0.33 mm near the start, and gets up to ~ 0.38 mm near the end. It also seems to be more prone to stringing than the red.

The properties of the green filament are somehow subtly different from the red, but I'm not sure what to tweak to fix it. I can try raising the temperature to make it a little "runnier", and I'm printing another cube now with a little less retraction.

Any other suggestions on how to get all 4 walls the same thickness?

Update: It's related to my retraction settings. I had "force retraction on layer change" turned on. If I turn that off, I get 4 walls of nearly identical thickness. However, when it does retract when printing a model, the first 14 mm or so will be under extruded.

I can certainly re-tune my retraction settings, but I'm surprised just changing color of filament makes such a large difference.

Update #2: Changing the retraction from 1 mm to 0.8 mm, and the extra restart distance from -0.1 mm to 0 seems to have fixed it. The green is definitely stringier than the red, and I may drop the temperature a bit to address that, but it's good enough for the first models I need to print.

Thanks!

airscapes
Posts: 344
Joined: Wed Jan 31, 2018 11:36 pm

Re: 1st Wall of Test Cube is Too Thin?

Post by airscapes » Thu Sep 05, 2019 6:37 pm

For extrusion multiplier I no longer use a single wall. I have found this leave you about bout 2-3 clicks under extruded. The reason was recently posted in the Simplifed forum, not sure I fully followed it but I have seen the same results at this fellow posted.

I use 2 walled squares to check starting height, and as a first check of Extrusion multiplier. Then I print a 2 layer square that measures 2 layers high. My first layer height is always set to 100% as I have no adhesion issues. The 2 layer model is the height of 2 layer so I have one for .2 .3. The ExtMult won't change with layer height like starting height does.

The finished printed 2 layers should have NO gaps between threads. As the first layer goes down shine a flashlight across the print and you should not see bed between the threads. Using these 2 models my parts are much stronger and more accurate as well as more air/water tight
I will attached the .2 and .3 modes of both the double and flat models. Make sure your infill overlap and perimeter overlap as set to 15% when doing these calibrations. I typically use 18-20 when I need strength over size perfection.

I have never needed more that 1.3mm of retraction, never wipe and never coast. Retraction is normally .90 -1.2 with pla for my M2. On occasions I have forgotten the point in front of .90 and that really mess you up.

Oh, measure your filament with your caliper. Esun is on the thin side and can be inconstant. On the "Other Tab" set the filament diameter to the average you measure over a few yards. I typically use 1.73 for Esun to start some rolls 1.72

Here is the post about not using single walls ans why.. I had been doing the above for some time before this was posted.
https://forum.simplify3d.com/viewtopic.php?f=8&t=13746

Hope this helps!
2 walls at .4 3mm tall.stl
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2 walls at .4 2mm tall.stl
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2 layers at ..2 x 30x30.stl
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2 layers at .3 x 30x30.stl
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