# Damage to bed surface from heat or chemical or..?

The original bed surface of my Ender 3 has become brittle and finally cracked, requiring replacement. I'm trying to figure out what the cause might have been to avoid it happening again. It seems to have started after using "flex PLA", which involves both high temperatures (225 °C) and plasticizers mixed in the PLA. Could either of these have contributed to the problem? I'm not sure what material the bed surface is - it's the new one that's removable and held on by clips. If it's PEI, the glass transition temperature is supposedly 217 °C, just above what I use for normal PLA but well below what I'm using for the flex, so perhaps that's the cause?

Image of the damage:

The build surface on the Ender3 is a BuildTak clone. The picture is a bit unclear, but given my experience with BuildTak (clones) this certainly damage because of heat. You can, as suggested before, replace the bed surface, but I do not think it is necessary at this stage.

Normally these surfaces do not get damaged that easily but to prolong the life try to keep the following points in mind:

• Correct height between nozzle and bed.
• Don't let the nozzle heat up/cool down close to the bed (for example after a failed first layer).
• When using sharp tools to remove prints be careful nut to dig into the surface.
• Don't use too high of a bed temperature (my BuildTak clone once had bubbles forming because the layers separated)
• Clean/degrease the bed, although this is more to ensure proper bed adhesion.
• I found out that if the bed stops sticking you can revive it by sanding it a bit.
• It is necessary - it's hard to tell from the pic, but around the two cracks it's lifted enough to make bottom surface of prints non-flat, and the nozzle scrapes on them and could dislodge first layer depending on exactly where it runs. – R.. GitHub STOP HELPING ICE Apr 29 '19 at 12:47
• Thinking about it more, I recall one print that stuck to the bed really badly, and feeling like I was breaking the adhesive under the bed surface when I eventually got it off. It seems plausible that, after that, thermal conduction away from the affected area was poor, and combined with a few bed height mistakes with hotend at 225 (and one with the first few layers of an aborted print still on the bed), that might have resulted in heat damage. – R.. GitHub STOP HELPING ICE Apr 29 '19 at 22:56
• Re: cleansing and sanding, if anything I have too much adhesion, so I think I'll pass. :-) – R.. GitHub STOP HELPING ICE Apr 29 '19 at 22:57
• @R.. yeah, I have the same, but sometimes because of hand grease the bed adhesion suddenly fails ;) – E Doe Apr 30 '19 at 14:00
• @R.. If this answer answered your question please click on the checkmark next to it. – E Doe Apr 30 '19 at 14:05

The material used for the Build surface is not PEI but a BuildTak Clone that offers adhesion through a rough surface texture. I do not know what exactly is in the composition of the polymer, but I can say that my bed surface needed replacement about 9 months after purchase after I vigorously removed a piece I printed. As a matter of fact, most build surfaces - even PEI - are pretty much going to wear out over time and need occasional replacement. Luckily, a build surface isn't expensive usually.

To prolong the life of the bed surface, I suggest:

• check the nozzle distance to the bed, as printing too close can make plastic residue extremely hard to remove.
• be very careful when using sharp tools to remove parts - don't let a corner bite into the surface!
• don't use a soldering iron or hot air gun on the build platform to remove stuck parts, you'll melt the surface and degrade it
• clean the surface at times.

However, replacing the bed is easy enough, as I found out here.

• Re: "here" link, my Ender 3 is the newer one without the surface glued to the aluminum, but instead to a removable non-metal plate. So removing the adhesive residue might be different. – R.. GitHub STOP HELPING ICE Apr 29 '19 at 12:44
• @R.. you would still pry the bed off, then remove the 3M adhesive that holds the Build Surface to the steel and then add a new. – Trish Apr 29 '19 at 18:12
• The adhesive came off almost entirely just by peeling, and the remainder came off easily with paint thinner. Whole replacement took about 5 minutes and \$6 (well, \$12 for 2), so not bad at all. – R.. GitHub STOP HELPING ICE Apr 29 '19 at 21:14
• @R.. when I did it, I got myself a pack of 3, having some spare beds and nozzles around never hurts, keeps the downtime for these wear-out parts low. – Trish Apr 29 '19 at 21:18
• Yeah. Actually I wish I could find identical replacements for the plate it adheres to. I'd buy an extra or two just to have them ready in case of future damage. Already have lots of nozzles. First pack I bought was assorted sizes, which I still haven't tried, but quality seemed really bad. Now I've got a bunch sold by Creality that seem to be same as original. :-) – R.. GitHub STOP HELPING ICE Apr 29 '19 at 22:36