Shards of glass bed stuck to ABS print (Ultimaker 3)

[rpierce 2]

Hey guys, I just got the UM3 about two weeks ago for rapid prototyping of electronic enclosures for the company I work for.  I have done 10 or less total prints so far using PLA, PVA, Nylon, and most recently ABS.  I just had my second ABS print ever take off a fairly sizable shard of glass from the build plate.

It was about a 17 hour print, but it ran during the day and finished overnight so it had plenty of time to cool (~4-6 hours).  It also was not hard to remove from the build plate, i scraped a corner up with a razor blade, heard a little pop, and it came off with no problem......except for the missing glass stuck to the part.

EDIT: I should also add I'm using the most current version of cura, with Ultimaker brand blue ABS, at unedited recommended settings aside from retraction settings

Also, the only bed adhesion used was a default sized brim and a thin coat of the supplied UHU stick spread around with a wet cloth

Anyone else have this problem and know a way to avoid it in the future?  I REALLY do not want to have to replace the glass print bed after every few prints.

Edited April 12, 2017 by Guest

[gr5 2,192]

Oh yeah. That sucks. I've probably done 1000 prints and that only happened once. I think it was CPE. I don't that's ever happened to me with ABS or PLA. I flipped the glass and it hasn't happened since.

This is rarer than you might think -- it's unlikely to happen very often.

I would contact your supplier just to see what they say. They might send you a free glass. Also consider contacting fbrc8.com - they might either send you a free one or at least they will quote you a price. There is a type of glass called neoceram that is probably better (flatter but might still spall like yours did). I should get off my butt some day and see if I can get a large shipment and sell those at a good price in my store.

Are you certain it was ABS? And not CPE or PET or UPET?

[rpierce 2]

Right away I want to say how great the customer support people are at fbrc8. They've already responded and gotten my information for a replacement glass platform, and I even sent that email after I posted this thread.

Everyone seems to say its a temperature issue and to let the glass cool before removing the part but it had hours to cool and was at room temperature when I removed it. People also say their parts are hard to remove when it happens but this print was just as easy to remove as any of my other prints and only required a little scrape under the edge of one side with a razor blade. I honestly don't really know what I could do differently other than print onto the bare glass and hope I get good adhesion and no warping.

The material should be ABS, as this is the box it came in.

[Dim3nsioneer 557]

I'm not a fan of mechanical tools to get prints off the glass. Usually, I put the glass into the freezer for an hour if I used some adhesion agent. People who are in a hurry should get a second glass plate for fast exchange. The active levelling of the UM3 makes the swap quite easy.

In this special case I guess the glass just had some weaknesses. I expect you to have less problem with the replacement you got.

[geert_2 558]

If the print was easy to remove, and the glass at room temp, then I guess it broke already while cooling down.

I also had this once, but with PET. The model was difficult to remove, but not exceptionally hard. While cooling, I had already heard some weird cracking sounds, louder than the normal sounds of the print coming loose. So I guess if it cracks, it is while cooling, due to the differences in thermal expansion.

Maybe some sort of fatigue in the glass, or just a weak point due to a scratch or so?

[gr5 2,192]

Right away I want to say how great the customer support people are at fbrc8.  They've already responded and gotten my information for a replacement glass platform, and I even sent that email after I posted this thread.

Well that's great. Now you'll have 3 perfect sides of glass to print on instead of 2.

[tomnagel 126]

Ultimaker ABS has a very strong adhesion to glass. It's actually too good, that is why glue is advised. The glue is actually the breaking layer between the glass and your ABS object.

We've never tested the thinned glue layer as you describe.

[rpierce 2]

Well that's great.  Now you'll have 3 perfect sides of glass to print on instead of 2.

Hopefully I don't end up with any other parts decorated with glass, but you never know. I started the print again on the other side of the plate this time with only a brim and no adhesive. It's about 5 hours in and everything seems good so far, which is surprising for a part that's about 8" x 6" in ABS. I'll be pretty impressed if I can print this on bare glass with no warping or problems.

[tomnagel 126]

Please read the "how to print with Ultimaker ABS" document on the website.

It says:

 

When printing with Ultimaker ABS you must apply a thin layer of glue (included in the accessory box of your 3D printer) to the glass plate. Not using the glue results in a high risk of chipping the glass plate when removing the print and may void the warranty.

Please note that it may be easier to remove the 3D prints from the build plate if it is still slightly warm at approximately 40ºC.

[rpierce 2]

I guess that makes sense.  Maybe the layer of glue was too thin from spreading it around.  It was such a large part I wasn't sure how thin and uniform I could get the layer just by applying with the glue stick, but I will just apply it that way from now on.

So if I'm leaving prints overnight (90% of the time) it would be a good idea to manually raise the bed temperature to ~40C to warm it up a bit before removing the print?

[tomnagel 126]

Yes.