Removing parts that are really stuck to the PEI bed

I did searches for this and didn’t find anyone mentioning this, so here goes:

I almost never use a tool to get a part up, either with ABS or PLA.

Here’s what I do:

I print a skirt around the part, usually about 4 mm away and one layer high.

After the part is printed and the bed has cooled to around 40-50 degrees C, I apply isopropyl alcohol between the part and the skirt, all the way around the part, with an eyedropper. I apply as much as possible without overflowing outside of the skirt. The alcohol makes a nice meniscus where it touches the base of the part. Then I wait a bit.

The alcohol seems to pull itself under the part, through surface tension I guess. For a 4-cm or so circular column, for example, after five minutes or less I can usually simply lift it off of the bed. If not, a fresh application of alcohol and another similar wait, and up it comes. No prying, no stress on the PEI.

Usually the skirt ring comes up easily, after that. I use the leftover alcohol sitting on the PEI by wiping it around with a paper towel to clean the PEI, since it’s OK to use it for that anyhow.

It works somewhat better for ABS, since it doesn’t seem to stick as well as PLA, but it works well for both.

Example: Late last night I had an ABS part of about that size firmly stuck onto the bed, and didn’t have time to do any of that, so I just left it overnight as it was. When I got up in the morning it was still firmly stuck, and the bed was now at room temperature. I applied the alcohol, and within 10 seconds or so I started hearing the cracking sound of the part breaking itself free. Another 10 seconds or so passed, and I lifted the part off of the bed without resistance. The entire bottom was wetted by the alcohol, it had quickly crept into the space between the bed and the part.

I hope this helps!

– Mike

This sounds really cool. I’ll keep this in my back pocket next time I have a massive part that needs some help coming off. Let me know if anyone else has good results as well!

MikeO… you sir, are a foot… or a hip. I don’t know which one, but you are most certainly a leg end (or something like that).

3dprintdaddy, I can confirm that the IPA approach does indeed work. Since getting my PEI sheet for my homebrew printer, I had been getting better and better adhesion with ABS until I tried printing something with a 200mm diameter base. First two attempts wouldn’t stick, so I upped the bed to 120C and the nozzle to 270C. A few hours and a colour change later and I have a good print, stuck fast to the printbed. After the bed cooled down, the part just floated across the surface. Next set of prints I do, the parts are not as big, and one of them is stuck so hard to the bed that it snapped as I was trying to dislodge it. I found this post before heading off to work and tried it as soon as I got home. I put some IPA all round the part and in seconds it was completely free.

Of course, I was getting so frustrated with it last night with time running low before work that I took a window scraper to it, so now I have to get some very fine grit paper (or equivalent) to clean the bed in places.

Now I know what to do next time I may throw away the scraper so I don’t make the same mistake again.

MikeO, you have now been officially inducted into the hall of heroes.

Be careful, as excessive IPA use may have damaged the PEI surface.

To minimize any reaction between the isopropyl alcohol and the PEI, I always wait to apply it until the bed is at or below 50 degrees C.

It also works faster if the bed is even cooler, as then there’s more differential contraction between the part and the bed, and thus more stress on the interface that’s trying to pop the part off of the bed anyway.

The IPA trick didn’t work for me on a large print.

I printed one of those 5mm block calibration pieces scaled up 400% in blue ABS, to test dimensional accuracy and left it overnight to print. Cura indicated it would take over 5hrs to complete, and in the morning, the part was complete.

The print was really, really stuck to the bed. I was prying it at each corner with the knife and it wouldn’t budge.

I searched and found this thread, and tried some iso propyl alcohol (99%) around the edges. Even after leaving it several minutes, it was still properly stuck.

I ended up heating the bed to 120c and ripping the part off the bed once it heated up a bit and became flexible again.

Unfortunately the attempts to pry it off the bed with the supplied blue-handle knife has damaged the bed. Lumps/bumps where I was trying way too hard to lift a corner of the part.

For a large part like that, you may well have to leave it for a few hours, if it’s really stuck, and re-apply the IPA a number of times. One part like that I had needed overnight to let the stuff get under it, but it was just sitting loose on the bed when I got up in the morning.

It’s not ideal, but better than running the risk of damaging the PEI bed.

Also, you might heat the bed up to around 50C and then apply the IPA as it cools.

Do this upgrade and never look back.

If you’re consistently having problems removing parts from the PEI bed, the nozzle is too close to the bed. Give the Z-endstop a quarter turn or use Z-offset in slicing software.

I had found the difference between a part sticking too much and not sticking at all was measured in microns using ABS. And also it seemed to change from print to print. The bed level was not repeatable on my printer. When I pulled a print off, the next time I printed the bed often needed adjustment, or the Z height was off. So glad I don’t have to deal with that anymore after redesigning the bed.

I also experience a slight variation of Z-height each time I print. Luckily I print a lot of prototypes that requires multiple consecutive prints. Examining the first layer and adjusting the Z-offset g-code for the next print is my typical workflow. Luckily the PEI is pretty forgiving when it comes to ABS.

@billyd - I like the removable bed concept. I’ll probably adapt your design to fit a PrintinZ Zebra plate on top of the glass and heater. I’m going to try one last PEI bed from LB before my warranty runs out.