Can't Eliminate Blobs at Loop Start / End?

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kartcrg
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Can't Eliminate Blobs at Loop Start / End?

Post by kartcrg » Mon Jul 20, 2015 6:14 pm

I can't figure out how to eliminate these defects. I'm using stock MG PLA and Simply3D. I have the start point closest to a specific location so I can better observe the problem. I've printed this object 10 times, changing ooze control settings each time and nothing seems to have much effect.

Retraction distance has been between 1 - 2mm. (1 is better)
Extra Restart has been between 0 and - .4mm. (0 is better)
Coast has been between 0 and 1mm. (0 is better)
Turning off 'Only Retract Between Open Spaces' doesn't do much either.

Here is FFF as it sits now: http://www.filedropper.com/samm2test
I've really run out of ideas here and would greatly appreciate any suggestions. Thanks guys!
IMG_6703.JPG
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Bratag
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by Bratag » Mon Jul 20, 2015 7:01 pm

Is there any way we can default the image size when people post images? With an image this big I can make neither head nor tail of what the issue is supposed to be

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Jules
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by Jules » Mon Jul 20, 2015 8:16 pm

Your layer height at .3 mm is too large for the width of 0.4 that you have specified in your fff file. Keep the ratio of width to height at 1.8, (or more), for the best size bead. (So change the layer height to .2mm) And turn off the 110% first layer height. (Too much extrusion, no place to go.)

PLA usually does not need to coast, so you can turn that off. Once you have the extrusion rate corrected it won't create those blobs.

It's very important to calibrate the extrusion for each spool of filament using the writeup that Jin has at the link below. (Best thing you can do for yourself as far as getting trouble-free prints.) :D

viewtopic.php?f=3&t=1964

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kartcrg
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by kartcrg » Mon Jul 20, 2015 8:34 pm

Bratag wrote:Is there any way we can default the image size when people post images? With an image this big I can make neither head nor tail of what the issue is supposed to be
I feel you!

Image
Image
Jules wrote:Your layer height at .3 mm is too large for the width of 0.4 that you have specified in your fff file. Keep the ratio of width to height at 1.8, (or more), for the best size bead. (So change the layer height to .2mm) And turn off the 110% first layer height. (Too much extrusion, no place to go.)

PLA usually does not need to coast, so you can turn that off. Once you have the extrusion rate corrected it won't create those blobs.

It's very important to calibrate the extrusion for each spool of filament using the writeup that Jin has at the link below. (Best thing you can do for yourself as far as getting trouble-free prints.) :D

viewtopic.php?f=3&t=1964
Thanks Jules,

I actually still get the blobs at layer heights of .1mm and .2mm and also with first layer heights from 90% to 110% :? I did do the calibration for this spool and got it spot on but things might have changed since I've been messing with so many settings trying to get rid of the blobs.

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Jules
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by Jules » Mon Jul 20, 2015 8:43 pm

Dang!

Tell you what, I'll post my Makergear Black PLA fff file in a little bit here, modified for your extrusion settings. (Which means that you can just plug it in and print.)

I need to ask you though, which version of S3D are you using?

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kartcrg
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by kartcrg » Mon Jul 20, 2015 8:46 pm

Jules wrote:Dang!

Tell you what, I'll post my Makergear Black PLA fff file in a little bit here, modified for your extrusion settings. (Which means that you can just plug it in and print.)

I need to ask you though, which version of S3D are you using?
Really appreciate it!! 3.0.1

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Jules
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by Jules » Mon Jul 20, 2015 8:56 pm

Okay, the reason that i asked which version - how you treat the outline overlap changed between the two versions. (version 2.2 needed more outline overlap in order to get the infill to attach.)

I'm going to make a quick change.... then post. Stand by.

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Jules
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by Jules » Mon Jul 20, 2015 9:02 pm

And we're back.....

I used the concentric top layer for that shape, and upped your infill, which gives a much smoother surface result on rounded shapes.

Give the settings below a try, and see if it works.
PLA_MG_Black.zip
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kartcrg
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by kartcrg » Mon Jul 20, 2015 9:13 pm

Jules wrote:And we're back.....

I used the concentric top layer for that shape, and upped your infill, which gives a much smoother surface result on rounded shapes.

Give the settings below a try, and see if it works.
PLA_MG_Black.zip

Thanks mate, printing now. I'll let you know how it goes.

I will say that with your profile, the print time is 40 minutes as opposed to the 10 minutes its been with every other profile I've been using. I understand of course that higher quality means more time but I'd like to be able to do these draft prints quickly and I hope that I don't have to quadruple print time when the only thing I need changed is the blobs. If that's the case, I might just live with the blobs in many situations.

Thanks again!

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Jules
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Re: Can't Eliminate Blobs at Loop Start / End?

Post by Jules » Mon Jul 20, 2015 9:27 pm

Yeah, that's the increased infill (80% vs 15%) as well as the lower layer height. But i also have the printing speed slowed down a bit. If you just want to do a draft at the slightly slower print speeds (it won't add that much time) decrease the infill back down to 15%.
Last edited by Jules on Mon Jul 20, 2015 9:34 pm, edited 1 time in total.

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