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Is this a retraction issue?

Discussion in 'Troubleshooting' started by Eric Viglotti, Feb 19, 2018.

  1. Eric Viglotti

    Eric Viglotti Member

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    The attached seems to be happening on curved surfaces, some with PLA, more so with PETG. One picture I had the standard 1.5mm retraction and one I moved to 2.0mm retraction? Should I add more retraction, how far can I go with an R2? Or anyone seen something like this before? I can't seem to locate anything similar on the Simplify3D troubleshooting page. I'm using S3D and a Robo R2.

    Thanks!
     

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    #1 Eric Viglotti, Feb 19, 2018
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Depends on where the issue is. If it is at the end of the line then you really need to use the Coast feature of S3D. What is the Coast setting?
     
    #2 WheresWaldo, Feb 19, 2018
  3. Eric Viglotti

    Eric Viglotti Member

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    Fascinating, I'm new to S3D, but now that I look at it, the attached preview in S3D actually shows me the exact marks it's going to make and indeed that lines up perfectly with the actual print (I drew a red box around one of them in the attached). One of the original photos was just 1.5mm retraction and no coasting, and the other was 2.0mm retraction and 0.3mm coasting. Honestly when I look at the two of them, the one with coasting/2.0 mm retraction only looks mildly better in just a few spots. Thanks!
     

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    #3 Eric Viglotti, Feb 19, 2018
  4. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Increase the coasting maybe by a factor of two or three. Retraction usually only occurs before the hot end switches from printing to travel, the coasting will be before printing ends.
     
    #4 WheresWaldo, Feb 19, 2018
  5. Eric Viglotti

    Eric Viglotti Member

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    Very interesting stuff. Clearly more trial and error in my future, but like always any help is certainly welcomed to point me at the right trials for the trial and error.

    1. In looking at S3D's preview line by line, these marks are coming from when the line for infill ends at an orange dot in preview and starts for the inside perimeter (light blue dot). I tried to move coasting to 1.0mm and attached is what happened there sadly :(

    2. What's more concerning though is that this frail mess appears to be happening in other spots of what seems like successful print jobs. Attached is a picture of one from S3D where there is failure on a layer or two and then also an old GCode file I produced from Cura that is failing at the same layer. This file used to work just fine, so I'm thinking it's either an issue with the R2 entirely or my PETG filament (which doesn't seem tangled or anything). Have you or anyone seen this weird thing where there is failure/gap for a layer or two like this? I can try some PLA to change it up in case this is a PETG issue.

    Thanks in advance!
     

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    #5 Eric Viglotti, Feb 20, 2018
  6. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    It may be that your PET-G profile is set for a hotend temp that is just a bit low. I have found that PET-G <> PET-G <> PET-G so any change from one companies spool to another or just one color to another or even between batches of spools will magnify small anomalies in your profile. I usually experiment with small objects like Deprime and maybe something printed in VASE mode., They usually print fast and let you fine tune temps and/or retraction and coasting. Once it is really tuned well then it might only be the difference of hotend temps to get a problem spool to work well.

    PLA is much cheaper to experiment with, but since it doesn't behave like PET-G when heated, it is much harder to use it as a baseline for PET-G.

    With regard to the preview, don't rely on it 100%, you have to visually inspect the model. Also when you have big curved areas I find that randomizing the layer starting position can also help to minimize the marks left on the model..

    Coasting, I use around 0.70 mm for PET-G, your exact number might be different, but I feel that your current 0.30 mm is just too short. I use about 0.40 for my PLA profiles.
     
    #6 WheresWaldo, Feb 20, 2018
  7. Eric Viglotti

    Eric Viglotti Member

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    Sorry for the delay in responding, your notes were spot on. I neglected to remember that my original work in PETG was with a $50 spool of GizmoDorks PETG, whereas my more recent work that has been failing was in a much cheaper $25 spool from Hatchbox. I will do some testing with the Hatchbox spool at higher than 240, and perhaps contact them to ask what they think.

    As for the rest, this gives me plenty I can use to do some trial and error here.

    Thanks!
     
    #7 Eric Viglotti, Feb 21, 2018
    WheresWaldo and mark tomlinson like this.

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