PEI sheet lifting from bed  

Re: PEI sheet lifting from bed

usually a few heat cycles shrink the PEI back onto the bed...

did you use something to dull the grip of PETG on PEI?

talcum powder, rubbed over the bed and rubbed off, or forehead grease rubbed over the bed, usually do a good job... Gluestick also works but sometimes leaves marks on the model...
thinned down PVA glue has also been known to work as a release agent

try preheating " bed only" for ABS, 100 degrees bed temperature

regards Joan

Re: PEI sheet lifting from bed

Ya, as for a release agent, I tried using a generous amount of Windex wiped on the bed a couple times before printing. I might try the diluted PVA glue next time. Of course, I could try lowering the bed temp a hair as well.

Of course, being new to PETG, I wasn't sure, should one let the print cool before taking it off or does it do less damage if it is removed while the bed is still heated?

I think I may just replace the PEI sheet anyway. I sorta made a mess (scratched it up quite a bit) of it while trying to mash the bulge down. I even thought it was trapped air that was causing it and pierced it with a needle so now I have a pinhole in the PEI surface as well. Though I might try a few more heat/cool cycles to reduce the bulge before I change the PEI sheet just in case it does that to the next one.

Thanks Joan!

Re: PEI sheet lifting from bed

Cheers David,

changing the PEI is one pleasure I have yet to experience...
My mk2 has fared quite well, there are a couple of nicks where I have been over ambitious with the scraper... but it still works after loads of use,

my Mk3 build plate is still almost pristine, haven't even used the second side yet...

I have bought PEI but so far, not used it!

good luck with yours
if it flattens down, a bit of glue stick rubbed into the pinhole will make it less obvious
rub on, polish off, and bake remainder in hole to harden it.

regards Joan

with PLA... Re: PEI sheet lifting from bed

Hi Guys,

I am noob at 3d printing and I got my MK3 exactly a week ago. Yesterday I started printing a small box and I cleaned the bed with isopropanol as I have been doing. This was a 10+ hour print and when i lifted it off the sheet, the corners had lifted during print and this hadhappened to the pei sheet.

Using PLA, temps 210/60. I used prusacontrol to slice the stl files ( https://www.thingiverse.com/thing:2365572 ). Did the room cool down too much during the night? Would an enclosure have been helpful?

The print just popped of the bed as the corners had already lifted (giving me a warped print as well)

Any thoughts? is the PEI sheet stil usable? should I use painters tape on this side?

btw I did redo the first layer calibration as in a previous print it lifted of the bed, but did great with the two prints before.

cheerz
--pascal

Re: PEI sheet lifting from bed

Hi Guys,

I am noob at 3d printing and I got my MK3 exactly a week ago. Yesterday I started printing a small box and I cleaned the bed with isopropanol as I have been doing. This was a 10+ hour print and when i lifted it off the sheet, the corners had lifted during print and this hadhappened to the pei sheet.

Using PLA, temps 210/60. I used prusacontrol to slice the stl files ( https://www.thingiverse.com/thing:2365572 ). Did the room cool down too much during the night? Would an enclosure have been helpful?

The print just popped of the bed as the corners had already lifted (giving me a warped print as well)

Any thoughts? is the PEI sheet stil usable? should I use painters tape on this side?

btw I did redo the first layer calibration as in a previous print it lifted of the bed, but did great with the two prints before.

cheerz
--pascal

I wouldn't worry about those bubbled spots. I have encountered those after printing PLA as well. They will eventually go away with continued heat/cool cycles.

In fact, I'm finding that PEI is actually quite resilient. Even the bulged part I was concerned about above is showing signs of going away. It's not gone yet, but after a few heat/cool cycles, it looks like it's a lot smaller.

Re: PEI sheet lifting from bed

I wouldn't worry about those bubbled spots. I have encountered those after printing PLA as well. They will eventually go away with continued heat/cool cycles.

In fact, I'm finding that PEI is actually quite resilient. Even the bulged part I was concerned about above is showing signs of going away. It's not gone yet, but after a few heat/cool cycles, it looks like it's a lot smaller.

Thanks David.p61. ,

Saw later that Joan also mentioned that. Then i will just keep printing 😉

--p

Re: PEI sheet lifting from bed

We tend to panic when Our babies get hurt!!!...

hope all goes well for you.
regards Joan

Re: PEI sheet lifting from bed

Well, my final report on this is that the bulged part on my PEI sheet will not go away completely.

I have tried numerous periods of heating it up to 100 and cooling it down and, while it's made it smaller, it will not go away. I've even tried using a heated clothes iron on the top side of the bed while the bed was heated to give it sort of a double whammy and although it may have helped a bit more, I think it's gotten as small as it will get. (On a side note, that's an easy way to cause a thermal runaway error.) And although it's small, you can still feel it when running your fingers over it and it is still noticeable when looked at under light.

So, looks like replacement is the only option at this point. It's OK... that PEI sheet has seen its share of prints already, it's time to retire it.

Re: PEI sheet lifting from bed

Before you take the final step to replacement, try using the supplied acupuncture needle to make a hole right in the middle of the bulge and go through another heat cycle leaving it at 100 for five minutes before cooling down again.

Re: PEI sheet lifting from bed

Before you take the final step to replacement, try using the supplied acupuncture needle to make a hole right in the middle of the bulge and go through another heat cycle leaving it at 100 for five minutes before cooling down again.

I suppose at this point it won't hurt to give that another try. Just after it happened and I thought it wasn't going away, I had already pierced it on one edge, but can try another spot just in case that first spot is no longer effective.

Re: PEI sheet lifting from bed

I too have the PEI sheet separating from the steel. I'm using ABS and am on my 3rd roll of filament. Once I set the Z height "properly" all of my parts stick. Also needed to add cooling for ABS to not deform the first 1/4". I clean the plate with dish soap once a week, and wipe with isopropyl OH before each print. Some designs lift slightly in a corner or two. Sometimes I can add brim, or two layers to the part, or two layer wide supports that I break off after printing. The parts are not delaminating during printing and once the part starts I can let it run for hours without worry.

I'm suspicious that the issue is not the part lifting from the PEI but the PEI lifting from the steel. You can see from the enclosed images that the reflection of the PEI sheet reflects the bottom of the printed part. This part was printed with an 8 mm wide brim, 100% fill, and supports. I normally print at 20% fill however I wanted to be able to counterbore and tap holes on the part without knowing the printed ID of the holes.

Love the Prusa MK3. I have printed PLA using EcoCubes and MakerBots but find the Prusa much more reliable, slicing software has great capabilities, and I'm able to print ABS. I've been waiting to be able to buy the new powder coated build plates. Actually ordered the printer one year ago and changed the order after six months in order to start printing.

Re: PEI sheet lifting from bed

The PEI sheet is a consumable product. I have had my printer for 6 months. I have gone through one PEI sticker sheet. I have found the sheet to last longer if I reserve one side of a complete sheet for ABS and PETG. I have found them to be harsher on the surface.