Part Pulled Chip Out of Glass

[pyronaught]

I just had an ABS + glue stick print literally pull a chip of the glass off the build plate when it popped off during cooling. Now there's a divot in my glass, what is up with that? Is this common and is there any way to fill the hole that would withstand the heat?

Normally I knock my parts off the plate by sliding a glass scraper into the base before the plate completely cools, but this was an overnight print so it cooled and popped off by itself. I suspect that maybe the forces can be stronger from the part shrinking as it cools and the chances of damaging the glass might be higher when letting it cool to room temp.

[jimc]

common issue. i hear that happening to alot of people. one reason why i went to aluminum tooling plate.

[KiddingMe]

Cracked mine recently too but happened while trying to pry off a cooled part. A chip of glass remained stuck to the print. This happened while using glue stick also. Guess the glue stick is working too well for us

I continued to print on the glass off to the side for awhile but finally bit the bullet and bought a new glass from makergear.

I also tried a cheap window glass from Home Depot but it was not flat enough unfortunately.

viewtopic.php?f=8&t=1807

[jereywolf]

common issue. i hear that happening to alot of people. one reason why i went to aluminum tooling plate.

Jim, do you have any issues with warping? What bed adhesion method do you use? Did you get an anodized sheet?

[jimc]

Only get warping with high warp materials like abs or nylon. The bed material isnt going to stop that 100%. I always thought the aluminum bed helped a little though because it heats so evenly. I only get a 2-3c difference from the center to the outer edges compared to 20+ on glass. For me the aluminum is durable and just works every time. I dont ever need to guess or change methods. A couple other guys here in the forum have tried it and had problems getting it to work which i have yet to understand. Hairspray is hairspray no matter what its put on top of You can also put kapton down with abs slurry which is really a rock solid way to go and the even temp really helps there.

[jdacal]

I broke a couple of glass plates when I first started. But I was applying too much force, and sometimes not letting the print cool enough.

What I do now is I use a wide razor knife, the kind that's kind of like a scraper all around the edges of the print. Then I use a really thin spatula, pushing it in all the way around the print until it just gradually loosens all around then pops out.

Someone recommended this spatula a while back on this forum and it really works great, after using the razor blade to loosen the edges of the print:

http://www.amazon.com/gp/product/B000NP ... UTF8&psc=1

[jereywolf]

Only get warping with high warp materials like abs or nylon. The bed material isnt going to stop that 100%. I always thought the aluminum bed helped a little though because it heats so evenly. I only get a 2-3c difference from the center to the outer edges compared to 20+ on glass. For me the aluminum is durable and just works every time.

Very cool! The even temperature is something that I have never thought of. I hardly ever have warping with ABS on glass with a pruple glue stick.
I'm really interested in the aluminum because of the thickness tolerance. .005" is a lot better than .015" on that first layer.

Where did you get your plate, and did you mill it to size afterwards?

[jimc]

i got my plate from mcmaster. you can get it 12x12". i have a nonferrous blade for the tablesaw. i just cut it on that. i glass bead one side of the plate to give it a finish like frosted glass. a couple very heavy coats of hairspray fills the pores and leaves a skin over the aluminum to print on. just a light mist between prints is all thats needed. after 10-20 i was with hot water and a scothbrite pad then start over. you can flip the plate over to the smooth side to use kapton, blue tape or whatever you want. my disclaimer.......like i said it has always worked fantastic for me BUT after the other guys didnt have luck with it i will say... your mileage may vary. you said you have good luck with glue stick. now i cant get that to work with abs at all. no idea why.

[hybridprinter]

Surprised the aluminum is perfectly flat? How thick of aluminum sheet?

[jimc]

1/4" mic6 tooling plate. its cast, stress relieved and milled flat on both sides. of course how its stored by the distributor can affect flatness. mcmaster has been good so far.