White Stains on Part  

Paul McGarr
Eminent Member

I am printing ASA, but I think I've seen this before with other materials.  Anyway, does anybody know what the white spots are?  Below are two pictures, one of the whole part, which is approximately 1" x 2" x 1/4", and one closeup.  Is this plasticizer that has migrated to the surface?  I am using a clean textured bed and I have been running parts for a while so I suspect the nozzle is free from residuals of other filaments.  I have noticed that after the bed cools, the majority of parts release from the bed completely by themselves.  Some stay lightly stuck though and those usually have the white marks.

[caption id="attachment_30139" align="alignnone" width="600"]

White Stains (near edge)[/caption] [caption id="attachment_30145" align="alignnone" width="600"]

White Stains (closeup)[/caption]

Posted : 15/05/2020 12:21 pm
Trusted Member

I have this also. I think it is not a 'stain' but microfractures in the plastic. This occurs with prints that adhere tightly to the bed and when pulled off will cause these fractures in the plastic.

It can occur with any plastic but more with PETG  and ASA which tend to stick to the bed more.

It also seems more with the textured sheets. I think this is because the small 'bumps' on the surface adhere better and 'pull' the plastic causing the fractures.

Just my ideas. Maybe someone with a microscope could give some more options.

Posted : 15/05/2020 1:49 pm

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