PEI Bed Surface

[jdacal]

To cut the PEI I use a straight edge metal ruler as a guide, then score it with a box cutter (with a good blade) a couple of passes, you do have to press down firmly both times. I then put the score along the edge of my workbench and give it a good downward whack with the palm of my hand. Breaks off cleanly. I've done about 4 so far and have not had an unclean break yet.

Also I find it easier to put the adhesive on the PEI first rather than on the bed. I used to put it on the bed first.

EDIT: One other thing. I read that applying heat helps the curing process when applying to metal, but not necessarily for plastic. I tried heating the bed to about 60C this last time to see if it helps adhesion. Time will tell.

[Jules]

To cut the PEI I use a straight edge metal ruler as a guide, then score it with a box cutter (with a good blade) a couple of passes, you do have to press down firmly both times. I then put the score along the edge of my workbench and give it a good downward whack with the palm of my hand. Breaks off cleanly. I've done about 4 so far and have not had an unclean break yet.

Yeah, that's what you do with a plastic cutter too - score it with a straight edge and then break it against an edge. I did the first one with a box cutter, the plastic cutter just cuts a deeper gouge out of the plastic so you don't need as many passes. Gouge once deeply on either side of the PEI, and put your weight on it. (Much easier on the hands.)

[swbluto]

Do the white markings on the PEI left behind by ABS prints transfer to the bottom layer of your future ABS prints? (I know if residue is left on a glass bed, it'll transfer to the bottom layer and was wondering if the white markings on the PEI also transfer to the ABS. Or, maybe those white markings are more like signs of stressed plastic and don't transfer at all. Inquiring minds want to know.)

I know the white markings will accumulate over time, just like they did with the plexiglass I tried out once, but it'd be rather cool if they didn't affect the quality of prints.

[Farr0wn3d]

I got my PEI and tape in the mail and installed it right away. I've been printing with it most of the day and while PETG does stick to it better than glass alone, that tape is brutal. the thickness of the tape is extremely inconsistent. Leading me to wonder if it would be better off to be laminated onto the glass with spray adhesive instead of the tape? has anyone tried this? I have high spots all over my bed from the tape thickness inconsistency

[Vandal968]

The tape is definitely tricky. Mine came off the roll a bit inconsistently on the edges and wanted to give me blobs. I cleaned it up a bit with an exacto before applying the PEI. I was worried that it wasn't level enough, but it's been fine. It's actually become more level with time ( a few weeks) and the small bubbles under the PEI are very slowly migrating out. A spray adhesive sounds like a great solution, let us know what you come up with.

cheers,
c

[Farr0wn3d]

Update on my PEI upgrade:

I ordered the thicker stuff and it came very flat, but when I applied it to the glass, the thickness of the tape varied WILDLY and left me with a lumpy print surface. I also put it on as-is (still shiny) and was very disappointed with how PETG was adhering to it. I flipped the glass over and tried the elmers extreme stick and liked it (with taulman alloy 910, not PETG) and I've been printing with that since. Until today. I had a PETG print that I needed to do so I bit the bullet and removed the PEI, got rid of the adhesive, cleaned and gave a good sanding with 2000 grit, then a light sanding with 800 to the print surface, and just clipped the sheet to the glass ( 6 clips in total, 2 front, 2 back, 1 on each side) and did a calibration print, they all stuck great! even the ones that were too far from the bed.

I saw that as a good sign and took my chances with going ahead with my large PETG print (20hrs) on the scuffed PETG. I'm 4 hours in and still no signs of warping. So far I'm quite pleased. The surface is nearly as flat as the boro under it, and it seems that the scuffing has made all the difference. seems to stick better than glue stick, and definitely better than the hairspray that I was using.

Thought I would toss in my 2 cents

[wmgeorge]

Where did you buy your PEI and tape at? Got all mine from Amazon and had none of the issues you had with the 3M adhesive. My only problem was getting the sheet cut.

Not sure if there is a high temperature spray adhesive?

[Farr0wn3d]

I bought both the tape, and PEI from the links in this thread. The adhesive on the tape was blobby and inconsistent. And as it turns out, not needed. While I had that large print fail on me last night while I was sleeping, it wasnt from a lack of adhesion (filament jammed in the drive) when I pulled it off the bed today, I just undid the 6 binder clips (forgot to mention you have to remove the handles off the 2 on the sides) removed the PEI from the glass, flexed it and it all came off great. It was on there very sturdy but the flexion pops it off quite easily. I would definitely recommend this method to anyone!

About the high temp adhesive spray, I believe that the 3M 90 spray adhesive is listed as heat resistant
http://solutions.3m.com/wps/portal/3M/e ... 274&rt=rud

[swbluto]

As awesome as PEI beds seem, the fact I'd have to wait until the bed completely cooled is absolutely a no-go in production environments. At least with glass beds, I can remove parts as soon as the temperature has decreased 10-20 degrees C so that I can almost immediately start another print after the bed has been cleaned. However, I'd imagine some of the highly intricate/delicate bottom layer prints I do would probably handle a PEI bed better in ABS.

[Farr0wn3d]

If you're in a production environment I would run multiple sheets and since all I have to do is remove clips to take off the PEI, you could toss on another one and away you go. the bed adhesion is incredible, I used to always have some degree of lifting off the bed, however small, or small support structures coming unstuck during a print but now that I have the PEI dialed in theres none of that. to me its actually better to do that option in a production role because you can replace the sheet with a ready one and probably even get printing faster, and with less failed prints due to bad adhesion