How To Apply Polyetherimide (PEI) to Borosilicate Glass for 3D printing. by eman717

Last crawled date: 3 years ago

If you haven't heard, this material is excellent for 3D printing when using a HEATED bed. Various plastics will stick to this, when at the right temperature, and release when cooled. It's pretty neat stuff. There's even a couple companies shipping machines with it already applied too.
If you don't have a heated bed, the "lamination procedure" would still apply, but you'd probably want to use a different laminate/material/substrate... I've had decent success with Buildtak+gluestick on a Rep 2, but I'm afraid of printing without the "gluestick barrier"...
If you'd never applied a laminate by hand, I've assembled a series of photos to show what I did to apply this material to my Rostock Max's round print bed.
Some Important Notes regarding PEI and avoiding having to do this again:

NinjaFlex/TPU sticks to this PERMANENTLY, essentially ruining it, BUT an application of a glue stick works to avoid it, just make sure you have a even layer of glue under your print... (I'd gluestick the bed, spray it with a little 1:5 Alcholol:water mix and spread around the glue with my finger so it's more even. works fine, never had TPU permanently stick).


This PEI material is pretty durable stuff, you can use a scrapper to get underneath stubborn parts without damaging it.


If you don't have you're bed properly calibrated, you could do as much damage to your nozzle and glass as the PEI. Measure twice, cut (or print in this case) once, but again, this is pretty durable stuff... poking a hole through it isn't easy.


You can easily clean this bed with a water/alcohol mixture, or straight acetone if you have some stubborn plastic adhered to the bed. I'd recommend using gloves when using acetone.


If you have adhesion problems, wet sand the PEI with 2000 Grit sand paper, a sanding block, and some mixed water & alcohol, wear gloves. Apply some pressure, very light though, so that the water begins to become milky. Sand foward/backwards, left/right as evenly as you can. Clean with water & alcohol. This will improve adhesion on PEI and doesn't wear away much.


A word of warning about sanding the PEI. A) it's probably not that healthy, so use gloves, and B) ABS, PLA, HIPS and PETG will stick REALLY good, maybe even "too" good, after a thurough sanding, especially if your first layer is too "squished"... so just be aware of that... you can always sand a bit more if a print doesn't quite stick, but it's hard to "remove adhesion" after heavily sanded PEI surface.


If you develop bubbles from the adhesive failing under the PEI (because your printing so much so often because your first layers stick so well after doing this.. ;) ....), but not the PEI.... you need to separate the bed surface from your printer and put it in the freezer, the adhesive will release the PEI super easily, which will allow you to reapply it with a new sheet of double stick tape... after you clean off the old adhesive from your borosilicate glass print bed of course... get some glue remover to help with this part... trust me... rolling your thumbs across the glue over and over for hours works too, but may incur blisters as a result...


To avoid those bubbles forming underneath the PEI entirely, you need to bake the moisture out of your double stick tape and PEI and off the freshly cleaned surface... in my case, it's this borosilicate glass. I used my printer to "bake" my sheets... but dont do that unless you have an enclosure and can get up past 110C... Alternatively using alligator clips and an oven would probably be more effective... just don't go too hot... 110C for an hour is probably enough.


I have also added a sheet of 1/16" copper I ordered off amazon to help more evenly distribute the heat of the heat bed.

I haven't had any bubble form under the PEI since doing this, this way.
p.s. don't mind the .AI file, it was so I could "publish" this.