Welcome to the SeeMeCNC Community

Hi everyone. I have a quick question about the glass build plate. I recently started printing with a new roll of ABS. I was having trouble with print bed adhesion, so I decided to troubleshoot the problem. I have about 40 days of print time on the printer and took the time to tighten all of the screws and nuts and tighten the belts. Then I completely recalibrated the Z height, I even retuned the PID loops. I still had trouble with the bed adhesion, so I increased my bed temp to 85. That solved my problem with curling, but now I have a new problem.

The last model I printed had a thin slice of build glass plate come off with the model. It's about the size of a penny.

Other info I can provide:
I only use elmer's brand glue sticks. I used the Purple kind but recently I switched to the "extra strength" white elmer's glue stick.
I didn't force the part off the plate. It was loose when I went to remove it. I find that the cooling of my prints naturally causes them to unstick.
I cooled the bed naturally at ambient after the print ended. I did not put it in a freezer or try to speed up the cooling.

Does the time on the printer cause the bed to "fatigue"? Or is there something else happening I should be aware of? I can use the other side of the bed but I need a new one now just to be safe. I don't want to keep breaking these things, so what can I do to make sure this is not going to happen?

Any thoughts would be appreciated.

Thank you!

yes the glass fatigues, and what you are using for glue is also a factor, its more a matter of uneven cooling as the parts of the glass not under a print cool faster than what is under a print. if the glue layers are really thick it seems to happen faster for me, so I wash my glass every 3 or 4 prints. Last time this happened to me, I had about 20 layers of purple glue stick on there...... Do turn your glass over, and keep a spare also, especially if you are doing any sort of production printing.

Tom C

stonewater wrote:yes the glass fatigues, and what you are using for glue is also a factor, its more a matter of uneven cooling as the parts of the glass not under a print cool faster than what is under a print. if the glue layers are really thick it seems to happen faster for me, so I wash my glass every 3 or 4 prints. Last time this happened to me, I had about 20 layers of purple glue stick on there...... Do turn your glass over, and keep a spare also, especially if you are doing any sort of production printing.

Tom C

Thanks for the advice! There's a glass shop about 20 minutes from here that say they can make us a new piece for 25 dollars. We're going to get some spares.

Just keep in mind that normal glass might not be able to handle the temperature fluctuations as well as borosilicate (Pyrex) glass.

The best option might be to add a layer of PEI over the borosilicate glass. That will allow you to print PLA and ABS with no other adhesives/glue. Plus the glass doesn't tend to chip/crack using PEI.

Check out this thread for more info: http://forum.seemecnc.com/viewtopic.php?f=36&t=7452

When I tried with normal glass the new sheet shattered first time I heat cycled it. You may get a little longer out of yours but I wouldn't pay for lots until you get one and run it a few times to try it out.

I bought a few Borosilicate ones after that - a little harder to find the manufacturer and cost a little more (surprisingly not much), and haven't had another one let go since I got the stack of them.

If you got the glass from SeeMeCNC about 4-6 months ago, I think they had a bum batch. Lots of people posting with that problem, including me, but I can say they have better ones in stock now. I ordered two replacements and they were a very different finish, and haven't even had to take the second plate out of the package yet.

Captain Starfish wrote:When I tried with normal glass the new sheet shattered first time I heat cycled it. You may get a little longer out of yours but I wouldn't pay for lots until you get one and run it a few times to try it out.

I bought a few Borosilicate ones after that - a little harder to find the manufacturer and cost a little more (surprisingly not much), and haven't had another one let go since I got the stack of them.

What source did you use for the Borosilicate ones?

Can't remember the name but they're pretty much the /only/ place that makes it in Australia.