Glass Build Plate Splintering. Advice needed.

[U.S. Water Rockets]

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!

[stonewater]

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

[U.S. Water Rockets]

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.

[KAS]

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

[Captain Starfish]

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.

[BenTheRighteous]

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.

[Eaglezsoar]

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?

[Captain Starfish]

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