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Better PEI build surface

Posted by pdtechBigBot 
Better PEI build surface
February 03, 2017 05:22PM
Many RepRappers are moving to PEI build surfaces for their superior adhesion to the 1st layer. I make large RepRap printers and realize the potential of PEI as a great build surface, but have found the 3M468mp adhesive which most places sell to be inadequate. When I print 600mm large parts in PETG, the PEI separates peels away from the 3m468mp, then the tape globs and makes a lump in the build surface. The 486mp is also a nightmare to remove from the bed. Overall, the performance of PEI with the 468mp is not as good as using 3m8992 (PET) tape, but with a better adhesive I believe it could be superior.

From my research, I see this forum: [forum.seemecnc.com] where they chemically bond PEI to aluminum, but that requires a dangerously hot plate to work well, and gets expensive. Does anyone have experience with the "Dauerdruckplatte" as they call it?

So after an hour on the phone with a 3M applications engineer, he responds with a list of recommended tapes and adhesives for PEI, and solidly disagrees with the use of 468mp. $100 of tapes and adhesives and a day of testing later, I find that 3M468mp performs better than anything the app engineer suggested (and was much cheaper) but not as well as epoxy. Epoxy adhered both aluminum and FRP to PEI twice as well as 3m468mp. So this is where I will begin my testing, which will be documented here.

If anyone else has tried such things or has interest in furthering the development of a better PEI plate, please comment below!
Re: Better PEI build surface
February 03, 2017 05:54PM
How thick is the PEI you're using?


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Better PEI build surface
February 03, 2017 06:23PM
1/8" thick PEI sheet. Thicker sheets are probably out of the question b/c they will get too pricey for 600x600 and are tough to find in that size.
Re: Better PEI build surface
February 03, 2017 06:26PM
...and I suppose the plate must remain somewhat disposable, as it is possible to ruin one of these PEI sheets somewhat easy:/

My next test will be with .003" PEI film and epoxy...
Re: Better PEI build surface
February 07, 2017 08:37PM
There are chemical processes that can coat on PEI, but they're expensive and really hazardous. Usually involving strong acid baths and temps between 80 and 250C.

or...

Could try some IPS Weld-On 3, is water-thin, quick drying and is mostly Methylene Chloride in composition. (to quote the sale pitch).
Polyetherimide (Ultem) is resistant to most solvents (glue), Methylene Chloride is one nasty chemical that can melt PEI.
Methylene Chloride is found in most paint strippers commonly found in hardware stores. Just be careful, and use only in a well ventilated area.
Re: Better PEI build surface
February 15, 2017 02:18AM
Has anyone tried UV curing adhesive. It would be quite easy to apply and place the pei perfectly squeezing out all the bubbles and then blast with UV. PEI probably doesn't let much through, but a longer exposure might do the trick. Even if 99% is blocked, you are looking at only a couple hours.
Re: Better PEI build surface
February 15, 2017 03:35AM
Thanks prot0typ1cal for the suggestion! I think I have some Weld-on 3 even! Hopefully it's still in there with the acrylic stuff, and yeh I'll try it out. The page I referenced below talks about chlorinated solvents: "PEI is resistant to most solvents but is soluable in some chlorinated aliphatic compounds. It is also prone to stress cracking in chlorinated solvents. Hence PEI does not lend itself well to solvent bonding."
...so I worry about it dissolving or cracking the PEI, but it's worth a whirl I think.

John Meacham : just curious, what are we trying to gain by moving to UV adhesive? My pull-strength test shows epoxy is best and has a nice work time and should be easy to apply. I'm most concerned that epoxy is very...permanent, and that it might not handle the thermal cycle. I'm thinking using .003" PEI film epoxied to an aluminum plate, but presuming the epoxy will never come off, and if a user needs to replace the PEI maybe they just glue another layer of epoxy on top of the old? Not ideal, but maybe ok?

there's a lot of info at the link below regarding PEI bonding. These glues are very expensive...out of reach for most RepRappers I think. They do mention epoxy as a solution, and recommend their flexible type B-45 or something like that.

[reltekllc.com]

I hear rumors that polycarbonate performs similar to PEI...do you guys know that to be accurate?
Re: Better PEI build surface
March 01, 2017 09:52AM
My single PC test (genuine Lexan sheet 1mm thick) was a failure. It adheres perfectly, the print becomes part of the bed smiling smiley
I glue PEI with Tesa 4965, lots and lots of small sheets. Never had an issue (max bed size was 300x300mm)

Now I've got rid of PEI and I'm using PrintBite. The ABS parts popping from the bed when it cools down is priceless.
Re: Better PEI build surface
March 01, 2017 01:00PM
Thanks Sigxcpu; my printer is 24"x24", and I avoid ABS for large parts. There aren't too many premade options for this size bed.
I had a similar experience with PEI and PETG...if it's too hot it fuses...but I guess we can say the adhesion was present. Perhaps lower temps would yield better results. That's the secret with PEI. I see where others identify this, and also claim the adhesion of the PC to the build platform is the weak link.

Anyone tried LEXAN with PETG and PLA?
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