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Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!

Posted by Andy1989 
Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 05:16PM
So iv been printing with my E3D volcano 0.8mm nozzle for months with no problems. Been using 0.5mm layers, E3D PLA, extruder temp 210, bed is float glass covered with watered down PVA heated to 55.

Last night I dropped layer height to 0.25mm just to see what happened, and used 70% hex infill for strength, and the result were awesome. Great quality, and much faster than my other 0.4mm nozzle.
The only little problem is when I came to remove the printed parts, huge chunks of my glass bed were stuck to the underside!!
This happened with all 3 parts I removed. I then took the glass off the printer to look at the other part and the glass underneath each was already cracked!

Guess the bed adhesion was just far too much, and this combined with super strong 70% 1.4mm wide infill was enough to break the glass!
The solution is obvious, drop the bed temp.
Just thought people might want to hear about this! Iv never heard of it before!

Ill post some images in a few min when iv find the right wire to connect my phone to my pc!
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 05:21PM
You can print straight onto the glass - no need for glue. Then you should have no problem.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 05:24PM
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 05:34PM
PLA straight onto glass, that's the first iv heard of that.

Will give it a go. When bed temp do you use?
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 05:43PM
I suppose this is why borosilicate glass is often used, to be fair I've heard this can happen but never seen it until now.


Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 06:18PM
- Get rid of any ABS -- worst material ever
- Replace ABS with PETG
- PETG @ 250C hotend and 70C bed
- PLA @ 230C and 50C bed (I don't use normal PLA)
- Use boro or tempered glass of decent thickness (picture frame glass is a NONO)
- Clean glass thoroughly with a good glass cleaner before each print
- Heated bed is a necessity

BIGGEST RULE EVER: --->> Wait until the glass is COMPLETELY cooled down to room temperature -- prints will pop right off

Edited 2 time(s). Last edit at 07/21/2016 06:20PM by MrBaz.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 06:55PM
I do like petg and its very strong, but it doesn't produce such sharp objects as ABS and it oozes all over the place, so its swings and roundabouts.


Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 07:13PM
Andy - for PLA I set the bed to 75C which measures 60C on top of the glass. For PETG I set the bed at 90C.
For PLA some glass cleaners can reduce adhesion. White vinegar works well.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 21, 2016 08:23PM
After 2 years of printing I can say that regular glass have some short life span when used as built plate, every certain number of cycles it crack or do what it did to you. It is cheap so keep few ofd them in stock.

Borosilicate glass will do the same, it will only take a little longer to happen.

I'm planning on switching my underside plate from aluminum to copper and will print on top of a detachable aluminum plate.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 22, 2016 09:30AM
One thing to note about PETG, I've had several large prints stick too well to the glass. Apparently, PETG is very harsh on glass, especially with large parts sticking too well. I did find an article that had the same problem with PETG I was experiencing and found those gorilla glass 9H glass screen protectors for ipads/tablets is better for PETG than borosilicate glass.

I bought a few for $10-15 on Amazon, but have yet to try them. It does not work with ABS apparently, but not sure about PLA or Nylon or other plastics besides PETG.

And I've had great success of 200C PLA sticking to a 70C bed to borosilicate glass without any intervention at the start or any additional items or treatments on the glass.

Edited 1 time(s). Last edit at 07/22/2016 09:33AM by PDBeal.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 22, 2016 03:40PM
I've occasionally had problems with prints sticking too well, but I have yet to see one take chunks out of my cast aluminum print bed...


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 23, 2016 07:13AM
Quote
the_digital_dentist
I've occasionally had problems with prints sticking too well, but I have yet to see one take chunks out of my cast aluminum print bed...
And propably never will, because aluminium isn't brittle like glass.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 23, 2016 08:36AM
Quote
DjDemonD
I do like petg and its very strong, but it doesn't produce such sharp objects as ABS and it oozes all over the place, so its swings and roundabouts.

Then you have something not calibrated correctly. I get sharp corners just fine.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 23, 2016 08:55AM
If you get too much adhesion on aluminium plate heat cycle it. If the part doesn't separate when the plate cools off, I usually heat it up to 60 degrees for a 15 minutes. Then I rapidly cool it down. I have 800g old CPU cooler in freezer to drop the temperature fast. usually I hear the part detaching quite fast with this trick.

As always, applying heat to plastic may change its dimensions. And don't try with glass, it will break.
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 23, 2016 09:18AM
Quote
MrBaz
Quote
DjDemonD
I do like petg and its very strong, but it doesn't produce such sharp objects as ABS and it oozes all over the place, so its swings and roundabouts.

Then you have something not calibrated correctly. I get sharp corners just fine.

The filament I've been using was ambiguously labelled as pet but I bought it as petg. It took a while to get the temps dialled in (it is petg) but it is still very prone to collecting around the nozzle then leaving blobs which strike the nozzle on the next layer. But I'm new to this material and learning the tricks as I go. Which is the fun part.


Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 23, 2016 09:26AM
Quote
Vuokko
If you get too much adhesion on aluminium plate heat cycle it. If the part doesn't separate when the plate cools off, I usually heat it up to 60 degrees for a 15 minutes. Then I rapidly cool it down. I have 800g old CPU cooler in freezer to drop the temperature fast. usually I hear the part detaching quite fast with this trick.

I don't get it. What do you do with the CPU cooler?


Son of MegaMax 3D printer: [www.instructables.com]
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
Re: Chunks of glass stuck to heated bed. TOO MUCH BED ADHESION!!
July 23, 2016 12:09PM
I put it on the bed when it is -20 and bed is 60 right after I've turned it off. I makes quite fast change down to 35 when it is standing there. It takes like 20 seconds or something. And the bed shrinks so quickly that the part usually detaches at that time
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