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I'm (surprisingly) having a problem getting my PEI substrate to stick to the heated bed surface. The ABS item being printed stuck great to the PEI surface. I've not seen anyone else post on this problem, but perhaps someone has seen it.

Note, this is the PRINT SURFACE warping, not the item being printed. That part went great with no delamination even on a large flat bottom.

I'm using 3M 468 adhesive to attach a PEI plastic sheet directly to the heated surface of my Flashforge Creator Pro printer. The heated bed is anodized black and the adhesive is a sheet cut to the requisite 6" X 9". It seemed fine and looked pretty good with few air bubbles when first attached, but the first print caused the edges of the PEI plastic to warp up from the corners of the bed.

It appears that the weak link is that the PEI detached from the adhesive. While this was not uniform, removal of the PEI sheet showed that 95% of the adhesive was still attached to the print bed.

The PEI has one glossy side and one matte side, and I chose to apply the adhesive to the matte side to get the glossy surface. Does this make a difference?

I applied the adhesive to the PEI surface just as it was after removing the protective plastic coating. I figured this was a clean as it was ever going to get.

I'd definitely appreciate some ideas on this.

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  • $\begingroup$ Did you clean the surface of the PEI? You also may need to sand it a bit to get it to stick to the tape but I haven't had any luck in finding someone else with the same issue as you. $\endgroup$ – tjb1 Jan 18 '17 at 13:30
  • $\begingroup$ I appreciate the thought. The PEI was very clean, but as someone else pointed out this may be due to different thermal expansion between the PEI, aluminum plate, and fairly large ABS footprint on the bed. I'll try attaching the PEI to a glass substrate as that's what many do. Gotta say, that this really surprised me as I'd not seen this sort of thing in the last year of printing. $\endgroup$ – Randy Steck Jan 19 '17 at 22:47
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Perhaps this is due to the aluminum build plate warping/crowning as it heats? I use a PEI print surface on my Monoprice Maker Select (Wanhao Di3), which has an 8.5"x8.5" build plate, and I've had no issues with the PEI coming unstuck. However, instead of attaching mine directly to the aluminum heated build plate, I attached it (using 3M 468) to a piece of Borosilicate glass, which is then attached to my aluminum build plate using silicone thermal heatsink pads. The rational for using a Borosilicate glass print surface is that a heated metal build surface is going to warp or move some, as the heat is coming from one side; the glass will not warp and so you have a completely flat surface on which to print (and the heatsink pads help make up the difference in surface geometry). I used this 3dprinterwiki article as the basis for my glass bed mod, and applied the PEI/adhesive using another source (which I've forgotten, possibly the RepRap wiki). While the first link is Wanhao Di3 specific, it covers the idea. Make sure you tweak your z-endstops if needed on your particular machine, as adding the glass plat raises the bed height by several mm.

Please note that I'm theorizing - I did not ever try applying my PEI directly to my aluminum build plate, so I have no direct comparison. But the use of glass to eliminate build plate warping/crowning is fairly well documented. See also this 3DPSE Answer.

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  • $\begingroup$ Excellent points, and with a bit more investigation I think this is almost entirely related to the aluminum heating and expansion. I know others have also bonded to glass substrates (not even borosilicate glass) with good results also. Just got it stuck down last night and will give it another shot today. $\endgroup$ – Randy Steck Jan 21 '17 at 16:36
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    $\begingroup$ As a follow-up on this topic, I've since remounted the PEI plate on the glass plate, but after sanding and reattaching using liquid to avoid air bubbles. I am not convinced that this problem was caused by the warp in the PEI sheet. It's not large, but PEI is not very conformable and the constant tension consistently lifted the edges. Mounting with the warp down has worked so far. $\endgroup$ – Randy Steck Feb 12 '17 at 18:03
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I never used one, but the thing that makes two parts stick together is the atmospheric pressure. The glue is just a thing that, even if it does not make any chemical bond, is keeping the air out. A pure example of that is if you put water in a glass and then put another one on it. Although the water is not glue you can't easily pull it up and if the surface is big you can't at all. It is the atmospheric pressure that keeps them together and the water keeps the air out ;). I suggest try the other side and see I'm just guessing . Good luck!!!

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  • $\begingroup$ Well since adhesives are all about chemical bonding with different strengths, the atmospheric pressure is a minor component to this. The cup experiment works not only due to pressure but also surface tension of the water. $\endgroup$ – Randy Steck Jan 19 '17 at 22:45
  • $\begingroup$ Well Not all adhesives are all about chemical bonding.Also i don t think that the issue is the heat expansion. Also the atmospheric pressure is underestimated here when you put your hand to a house vacuum,for example,the force that makes you hand stuck to the vacuum s end is the pressure of the atmosphere... en.wikipedia.org/wiki/Adhesive $\endgroup$ – Odysx2 Jan 20 '17 at 12:36
  • $\begingroup$ Is there any reason you needed to make two answers rather than one? You can edit your answer if you have something to add. Also, please proofread your answer. It is suffering from run-on sentences. Lack of appropriate punctuation makes it very difficult to read. $\endgroup$ – Tom van der Zanden Jan 20 '17 at 13:11
  • $\begingroup$ The second is a respond to the guy that said all adhesives are about chemical bonding.Now to you :English is not my mother language it took me much time to found way to write my answer as best i could...Please try to focus on the meaning and what matters..... $\endgroup$ – Odysx2 Jan 20 '17 at 13:49
  • $\begingroup$ @Odysx2 I understand that, but in any case, please try to make shorter sentences. If you put a lot of things together in one sentence like this it makes it very hard to read because you have to mentally break down the sentence in to parts and it is very hard to do that if there is no punctuation and the sentence just goes on and on without ever giving you a visual indication of how to split it apart. $\endgroup$ – Tom van der Zanden Jan 21 '17 at 10:24

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