Bubbles in PEI sheet

Hey all

Ive noticed large bubbles apearing on the bed of my taz 6 that went away when cool. Until now they’ve been outside of where ive been printing but now have come up like ive shown in the picture.

The bed isnt that old, bought it in November as the kit on the Lulzbot store. Is there an easy way of replacing it?

It’s very simple to do. I made a video taking you through step by step on how to replace the sheet. I do it on a mini, but the taz is the exactly the same process, just bigger PEI.

If you have any questions let me know. I’m happy to help!



I’m on my 4th bed. All have delamination issues. Just today I peeled back a corner and squeezed out a huge bubble.

Thanks Jim I’ll take a look.

Is there a warranty on parts ordered from Lulzbot? I am thinking of just getting a replacement. I am part way through doing the openbuilds rail mods from piercet so the printer is out of action so would be a good time to do it.

4th bed… what causes this? I use flat tools to remove prints and wait for the bed to move forward.

Letting the part cool off too much and usually prying up on parts even a little bit. I use a chisel flat against the bed to remove my parts. The tool supplied by lulzbot always had me prying on the bed. Sheet will need to be replaced, they do wear out eventually. I’ve had less bubbles since moving to my chisel method.

Lulzbot used to replace the bed assembly under warranty in the beginning but they do not any more. Head to the Lulzbot store and order yourself a new sheet of PEI. I always keep a spare sheet in my print room just in case something happens to the bed.


The common belief is that moisture is getting in between the PEI and Glass bed and the thermal shocks applied through heating and cooling eventually cause the delamination.

Yes, this has been a popular subject. No matter how careful you are the adhesive between the PEI and glass will fail eventually from the heating and cooling. The higher the heat on the bed, the more prone to bubbling over time. I have been through many PEI sheets and keep an extra bed assembly ready to roll when a working bed goes too bubbly to use. As an experiment, I have been running two identical printers, one with low heat bed filaments like nGen and one with high heat bed filaments like HT and XT. The high heat bed temps definitely bubble more than the low heat bed. So when I changed the high heat bed PEI last time, I went with a 40 mil sheet of PEI and that one shows no bubbling so far after a few months of constant daily printing. Here’s some links to find thicker PEI sheets if you’re interested.



Thanks for the input guys. I am gonna try for a thicker sheet an see how it goes