Retraction or cooling issue on Lithophane  

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Andrew
(@andrew-5)
Estimable Member

Hi. 

First ever attempt and although the base layer is fine the top layers have "jaggy fur" all over the place. Not too much of an issue when the top layer is going to be flat but looks really bad on lithograph. It looks a bit like when the layer height is too low and the nozzle drags but on this model it only appears where the nozzle retracts. Is it simply retraction I should tinker with or is it perhaps cooling too quickly......or something else.

Thanks in advance

 

Posted : 20/05/2020 11:53 am
Andrew
(@andrew-5)
Estimable Member

Better picture of Jaggy Fuzz.

 

Andrew

Posted : 20/05/2020 12:00 pm
Neophyl
(@neophyl)
Famed Member

Lithographs are normally printed in a vertical orientation precisely for this and similar other reasons.

Posted : 20/05/2020 12:15 pm
Andrew liked
Andrew
(@andrew-5)
Estimable Member

Trying that right now. I was following the instructions from the site that converted the image. So far so good....only issue appears to be brim isn't touching the model as specified which is a bit worrying. I expect the pla to lift but hope it wont.

 

AD

Posted : 20/05/2020 1:13 pm
Neophyl
(@neophyl)
Famed Member

@andrewld

If you are using the default prusa profile its likely the elephants foot compensation setting.  By default they have it at 0.2mm which shrinks the first layer by that much to compensate for the first layer 'squish' to get good adhesion.  I find that value to be too much so mine is set to 0.1.

The other alternative to using a brim is to right click your model, add a modifier, size it such that its bigger than the part (so where the brim would be in size) and then make is 0.2mm high and drop it to the bed around the part.  Instant big base that will act as surface area on the bed.  You can then generally peel/snap it away from the main part fairly easily.

Posted : 20/05/2020 1:19 pm
Andrew liked
Andrew
(@andrew-5)
Estimable Member

@neophyl

Thanks I will look into that. Currently printing a small sample to test using a raft......yes the last one did lift off the bed. 🤣 

Posted : 20/05/2020 2:17 pm
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