PC Blend & PEI  

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martin.h27
(@martin-h27)
Active Member

I have tried my first print with PC Blend, and I love it. No problems whatsoever, the part seems to be incredibly strong. Well done, Prusa!

However, it seems that PEI isn't so happy with the material and the temperature. I have used the supplied glue stick, and the parts separated easily. That was not a problem. However, there're clear contours of the parts on the sheet, plus it seems that its layers separated a bit at few sport. Nothing horrible, but neither something that I would be happy about.

Since I also have the powder coated sheet, should I use it instead? Will it sustain less damage compared to PEI?

Thanks!

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Posted : 28/08/2020 9:32 am
charles.h13
(@charles-h13)
Famed Member

To be honest, I have never used my non-textured fro PC Blend.  I have had challenges with ABS on them so I just never ventured to that sheet with PC blend because it tends to overstick more than ABS.  I just could not imagine the challenges I would have with PC blend on the sticker sheets.  

Posted : 28/08/2020 10:17 am
jsw
 jsw
(@jsw)
Prominent Member

I get clear impressions (photographs?) on the smooth PEI sheet when I do ABS prints, particularly when I do several of the same model.  I would describe these as mostly images and not actual contours.  If there's a contour, I think it's mostly in the residual glue stick (or Layerneer Bed Weld) and not in the coating.

These seem to fade over time, but in the sheet that I use most for ABS you can see the images as outlines of several parts that have been recently printed.  I have yet to see the image of a previous print appear on the bottom of another print, however.

I noticed it when I did the PC Blend prints, but didn't think it was worse than with ABS.

I also agree that the PC Blend is good stuff.

Posted : 28/08/2020 10:59 am
martin.h27
(@martin-h27)
Active Member

This is how my sheets look like. The "photograph" is a little "3D" - not much, but the surface is no longer perfectly flat. There are no residues of the glue, it was carefully cleaned with Isopropyl alcohol. 

What puzzles me is the other side of the sheet - I have never printed on it, and it is one week old. 

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Posted : 28/08/2020 12:11 pm
Neophyl
(@neophyl)
Noble Member

Its the heat effecting the glue that bonds the pei to the steel.  You often see these with higher bed temps.  Usually they disappear over time as you print and the gasses? that cause the bubbles are reabsorbed.  The usual advice is to turn it over and use the other side for a bit but looking at yours that may not be possible.

It may be worth contacting support via chat.  As they treat these as consumables you might not get help but its worth a shot. 

Posted : 28/08/2020 12:18 pm
martin.h27
(@martin-h27)
Active Member

@neophyl

Thank you, makes sense. I'll try to talk to support, let's see what they think...

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Posted : 28/08/2020 12:33 pm
jsw
 jsw
(@jsw)
Prominent Member

Here's a close-up of a sheet that's had several hundred prints.  You can see the images of several prints there, plus the brush strokes of recent Layerneer Bed Weld adhesive.  None of this, however, is '3d' to the extent it can be felt.

Posted : 28/08/2020 5:00 pm
martin.h27
(@martin-h27)
Active Member

@jsw

Thanks. Yeah, this seems "normal", I have definitely seen this before and it wouldn't worry me at all. But the outline of the parts on my sheet definitely can be felt when you run fingers over it.

Well, let's see what the support has to say...

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Posted : 28/08/2020 5:20 pm
charles.h13
(@charles-h13)
Famed Member

Yup.  You can get this also with ABS.  

Posted : 28/08/2020 7:12 pm
martin.h27
(@martin-h27)
Active Member

Support told me that this is normal, that bubbles can form before "the glue stabilises".

Supposedly heating the plate for a while to 90ºC should help to mitigate the situation (which I still need to test).

This effect (when printing with high bed temperatures) should be less pronounced over time, but may not disappear completely.

So I guess that I'm not going to torture the PEI sheet again with 110ºC, and I will rather use the powder-coated one for PC...

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Posted : 31/08/2020 8:43 pm
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