PLA isn't sticking to PEI.

I got a PEI sheet and applied it to my glass build plate. At 70C, PLA isn't sticking to it. It just sort of peels right off, and printing circles and arcs is impossible as the extruded plastic just doesn't stick to the bed. I've wiped down the PEI with a lens wipe, so it should be clean. '

I've heard so many people laud PEI for not needing any additives, but for me it's performing worse than bare glass. Am I being dumb? Is PEI not for PLA? Is 70C to high (though others have reported that 70 is fine)?

Here's my S3D profile. I'm using the matte side of the PEI.

Adjust the Z=0 position...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I'm afraid it isn't that simple. I can lay straight lines onto the bed. First layer is exactly 0.20mm thick, just as I've set my slicer. The bed is pretty level, at +- 0.03mm per corner. Z height is about as perfect as it gets.

When turning corners however, the PLA doesn't stick.

I'm actually wondering if I was sold something other than PEI, because I have no idea what could cause this.

slow down.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Slowing down on the first layer fixed the problem, but I'm still not getting the kind of adhesion that everyone raves about. I still get warping, and a part just came loose while the bed was still heated.

move the nozzle closer

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I just switched to PEI and had to raise temp to 90c. Sticks great.

It might also be that the PEI you are using has too smooth of surface (Looks glossy?). Hit it with some 1,500 grit sandpaper until it's not glossy anymore, then clean it with some isopropyl alcohol. If that does not do it then as mentioned you need to lower the Z axis to give more of a push into the PEI.

Second on the isopropyl alcohol advice. 70 C might be too hot for PLA on PEI, maybe try 60 or 55 C. Otherwise, fine sandpaper seems like a great idea - or try flipping the PEI sheet over, the other side might be less glossy.

My advice: don't give up on PEI just yet - I recently got a sheet and it's the single best upgrade I've made to my i3, went from ~80% success with PLA and 20% success with ABS to >95% for both materials.

I've noticed PEI takes on greasy fingerprints and doesn't let go, even after cleaning with solvents. Use sandpaper. I use 600 or 800 grit. It leaves a nice matte finish and really cleans all the crap off the bed. Don't ever touch the bed with your fingers if you can avoid it (especially if they're greasy).

PLA should stick to the clean PEI at any speed with a surface temperature around 60 degrees. I've had problems when the surface wasn't clean enough, and by clean enough I mean sanded.

Think about cleaning the surfaces of metal parts in preparation for epoxy: you don't use a hydrocarbon solvent, you use a mechanical abrasive.

99% isopropyl alcohol did the trick. 70% wasn't enough. Now PLA sticks well at 200/80C. Thanks guys. For the intrepid googlers out there, matte pei works fine after a cleaning with 99% isopropyl alcohol and a kimwipe or any other towel that doesn't leave dust on the build plate.

Oh wow, I thought it was just me that had this issue.

wanted to add my 2 cents to this thread even though it is a bit old. I have discovered that there are different materials being sold as pei sheet- I had a goo experience with my first pei bed and as I had gone through my learning curve however had managed to gouge it in several places.. I flipped it over and kept using it but was using it clipped to the aluminum bed- it didn't always stay flat which negatively impacted the first layer at times. I decided to get another sheet and glue it down with the 3m 468mp adhesive sheet. I ordered one on ebay.. and what came was quite a different material than my first sheet. The first sheet was clear or mostly clear and was fairly tough. The second one I ordered was white, opaque and had a matte finish. I had the same issues getting pla to stick to it as reported in this thread. and thanks to this thread, I was able to greatly improve adhesion cleaning the bed with isopropyl alcohol.. but it required cleaning before every print.. and even then large parts would peel up and most parts damaged the sheet when removing them requriing scouring to clean up- the original pei sheet never did this. I finally decided that the experience was poor enough that I was going back to my old pei sheet, and so removed the new one and the 468mp adhesive which only took about 10 minutes.. I expected it to be a much bigger ordeal after reading about others experiences. After using the adhesive to attach my original sheet, my stability and first layer quality has increased- I got what I was shooting for by adding the adhesive vs the solely clipped on pei sheet. So.. to sum up- pei is not pei is not pei. After doing another stroll through ebay and amazon, The more expensive pei sheet material is what I would choose- make sure it is the clear variety. I ended up going to gizmodorks and ordering a new sheet which I haven't installed yet.. will probably wait a while since I am getting good results. At any case the pei sheet that came from gizmodorks appears to be the same material I got the first time.. So be careful with the cheap pei sheet available on ebay. heck it is possible that the stuff I got wasn't even pei.

Yeah, kinda suspected this. My sheet was from amazon. [www.amazon.com] it's a translucent auberge color. One side is glossy, the other matte. I'm printing on the matte, and I'm using a sheet of 3M adhesive to secure it to a glass sheet. I have to clean the bed every print with iso and crank the bed temperature to get a reliable adhesion. But I've seen a lot of reviews for gizmodork PEI, mentioning how it isn't the "PEI color." No idea which one is really PEI.

FWIW, I got my PEI from gizmodorks via Amazon, it's 1 mm thick, light brown in color, super glossy. Is it really PEI? I have no way to know. What I can say is that I used them to source sheets for two printers, and in both cases I sanded off the gloss and stuck the sheet down with adhesive film and it works wonderfully for PLA. I tried it glossy, wouldn't stick. I tried it clipped, wouldn't stick. If it matters, I warm the bed to 60c, level to 0.03mm feeler gauge, and print first layers glacially slow, 20-25mm/s .

PLA should have some squish into the bed, this really cant be just measured. You have to observe the squish as the first layer gets put down it takes a bit of trial and error to get the initial Z distance to the nozzle right.
With PEI you should be able to heat around 50c and squish a first layer on quite nicely, even the 'fake' PEI sheets will work but may need more heat and clean the sheet with 99% isopropyl b4 every print.

50% or 70% will work but may leave some 'dew' on the bed that needs to dry b4 the first layer is squished in.

its also normal to have your first layer hotter than your standard print layers. around a 10c difference is common.
as with any filament, print your first layer slow.

Do a lot of first layer tests to figure out that sweet spot b4 you commit to hours of a print only to find it all goes for shit....

[3dprinting.com]

I am beginning to believe PEI is not PEI. my PEI is not clear and it warned NOT to use acetone to clean, though many places specify acetone. Maybe that is the clue.

I upgraded with a MIC6 plate and PEI sheet that came with the 3M already attached.
I do 3 point leveling and it is very flat.
bed level matrix
+1.000000 +0.000000 +0.000050
+0.000000 + 1.000000 + 0.000013
-0.000050 -0.000013 + 1.000000

I first ran ABS at 110°C and it worked almost perfectly. I did get a little warping on some prints, but it otherwise felt pretty stuck.
I tried PLA 2 days ago and a simple print with 100mm square contact area stuck well enough if I printed 1 but when I did 4 they got knocked over when the head went to a different piece.
A slight warp of the edge of a sphere caught the head. Printing one doesn't traverse the head across the edge so it made it to the end.
Then I tried a larger piece. More footing. came loose 1/2 way thru a 100 layer piece.
Cleaned the PEI with 91% isopropyl alcohol. BTW, the 70% rubbing alcohol contains glycerin so it is not good to use.
I added a 4mm brim.
I increased the bed temp to 70°C for first layer, 60 for the rest, and the filament temp to 210 from 205.
I ran the first layer at 20mm/sec.
I have cooling for the part.
I set the Z0 and from my measurements it is Z=0.00mm. I have a 0.1mm offset and when I raise Z 0.05mm after a Z home it measures 0.002" or 0.05mm
It is a piezo sensor and the repeatability STD DEV = 0.001718
I used babystepping to squash the first layer by up to 0.2mm.
nothing worked
I sanded the PEI with 600 paper and cleaned it. NADA.

When I printed a single layer test it seemed to stick. Maybe not enough.
What am I missing? I don't have any hair left to pull out!

Edited 1 time(s). Last edit at 06/27/2018 10:22PM by ruggb.

Just a note about isopropyl alcohol - there is 70% and 91%. Read the ingredients! 70% is often build as RUBBING alcohol. It contains Glycerin, which I would think is not desirable as it is a lubricant. 91% contains 9% purified water.
BTW, I still have not solved the PLA issue with my PEI - but I haven't actively tried lately.