Removing pla part from glass (glued, but not so strong: I removed with hands), a part of glass was removed too! Did it ever happens to you?!
Used to happen to me all the time when I first started printing. Eventually I understood the correct layer height a little bit better and was able to get adhesion, without getting super-adhesion.
This happens to me everyonce in a while. Its one of the reasons I like PET tape on the glass
I use an aluminum print bed coated with a thin PEI layer. It’s pretty much perfect. No warping, no detaching and no hassle with replacing tape every once in a while. As long the bed is hot the printed object sticks to the bed like it was part of the bed. The bonding is strong enough that I could literally lift the whole printer holding it on the object. After the print has finished and the bed has cooled down, the object detaches itself and can easily be taken off the bed. The PEI layer is diffused into the surface of the aluminum plate. It can be damaged by sharp metal tools. So don’t use metal scrapers to detach the object! The print bed has been the most valuable investment for my printer, yet.
I’ve had little chips come off, but not that big. I agree with @ThantiK ; it’s more common with an incorrect z height.
@Hendrik_Wiese where did you get a bed like that?
I have used both non-tempered glass, and
a mirror tile cut down to fit. I use Hairspray on the glass. it is rare to have it stick to the glass as the varnish from the hairspray will detach first. I tried Blue Masking tape, I have tried klapton tape with mixed results. so Far Glass & hairspray has been the BEST solution for me.
Sign makers and glass cutters actually used glue to chip glass to make signage and privacy glass in days of yore. @Ben_Krasnow chronicled his experiments along these lines on his blog:
Yes this has happened to me a number of times. I use cheap photo frame glass and UHU Stic for ABS and the glass weakens over time. I have had much larger flakes of glass come off.
Man, that is good adhesion!
I have cracked one glass in 4 years. Use glue stick and 3mm mirrors. +1 on proper z height.
Sand blasted glass is recommended. Good adhesion and easy to remove .
Same used to happen to me… then got some borosilcate (pyrex) glass from aliexpress… no problems any more… plus I feel safer that the glass will not crack under the heat… with PLA I just heat to 60c and as cools it pops off… ABS I use hairspray at 110c… spray plenty on evenly…
@Chapman_Baetzel
I’ve got it from this shop: http://reprap-fab.org/shop/product_info.php?products_id=110
AFAIK the shop owner produces the plates by himself. So I assume that if you need another size than about 200x200 you can ask him for that.
Wow, so many comments. Ok now I’ll try to add more infos. First of all: i have a delta printed. I spent some days calibrating it, and now it prints really well also large objects and nozzle stay on right distance. I have a round borosilicate glass bed (17x17). Both pla and abs warp or detatch from heated bed if I don’t put some glue. For abs I use an italian glue that works really well: abs stick and when heated bed goes under 60° it start cracking. On 30° it is detached. For PLA i used another glue. It was too strong, sometimes I needed to add some ice to remove pla (!). So I mix glue with some water (60% water / 40% glue) and now when temperature is down to 30° I can detach piece with some force (not so much). Maybe adding more water works better. But now it starts removing glass parts. Maybe glass was weaken from many tries I did with strong glue…
I’ve found you can avoid this by using bare glass with glue stick (I’ve got elmers stick, but many others are available) and to remove the object take it straight from the heated bed (~60c) and put it into the freezer. The change in heat isn’t enough to crack the glass but the difference in contraction between the object and glass is enough to make it pop completely off after about 5 minutes.
@Miles_Flavel I have had this happen to me with ABS and I have been using a glue stick. I now actually prefer to print ABS models that have less contact with the bed. I found that the more volume of ABS used, the greater the shrinking forces.
Again, I really recommend taking a look at PEI coated aluminum print beds!
I print on glass with hair spray. It sticks well but it can be hard to remove so I let the glass cool a little bit and then put it in the refrigerator or freezer for about 15 minutes. The print just pops off or even falls off.