1 (edited by jfabritz 2014-10-20 15:26:33)

Topic: Did part of my bed melt during a long print?

I have the DaVinci 1.0, bought it three weeks ago at Microcenter. My family has been playing around with it and so far so good.

However... I was trying to print a model someone had on Thingiverse of Space Lab Regula 1 from Star Trek. Took like 22 hours, but I noticed as it was building up its lower portion, which was two round cylinders surrounded by a lot of support, it started to sag on one end.

After removing the print when it completed, I noticed that one of the cylinders was glassy where it collapsed. After I cleaned off the bed, I noticed I now have a depression in the glass over the heating element! The glass appears to have melted underneath the model. :-(

Has anyone seen this before? I am going to talk with XYZ to see about a warranty replacement because this is definately faulty. Maybe the thermistor crapped out and overheated the bed? I dunno, but that was pretty bizarre.

Update: Title changed due to absurdity of it ;-) Well, sorta...

2

Re: Did part of my bed melt during a long print?

I don't know how you could possibly melt borosilicate glass and not have every part near it burned to a crisp. Even if it was "just plain old glass" the melting point would be around 900F or 500C.

I can't get my bed up to 120C without the printer deciding to alarm / shutdown if it attempts to print. I don't think the power supply could get the bed up to 150C even if nothing else was drawing power at all. I have no clue how even if the element was mostly shorted so only a small spot actually heated you could get to the kind of temp it would need to melt the glass, but feel lucky you had no fire if it did get that hot.

3

Re: Did part of my bed melt during a long print?

That's simply impossible - I would like to see a picture of what you are talking about, but there is simply no way that your print bed reached the 800C / 1500F required to soften borosilicate glass. Mostly because ABS auto-ignites at around half that temperature, at around 400C.

4

Re: Did part of my bed melt during a long print?

Yeah, perhaps melt was the wrong term, but a piece of the glass came off with the print. Here is a photo showing the ABS part that kinda liquified (for lack of a better explanation) and the piece of glass stuck to it.

I guess it is possible that when I was struggling to remove it after it cooled that the glass in that area was weak and a piece came off with it, but something doesn't seem right. I've never seen this before in the other prints I have done, where it looks like something else melted and flowed into or along the plastic.

Let me figure out how to embed a photo...

5

Re: Did part of my bed melt during a long print?

Okay, here are two photos.

One is of the divot in the glass bed (I darkened the area around it so you can see it easier), and the other one is the part that has the piece of glass stuck to it.

So maybe it weakened due to some unknown specific reason and came off with it, but the strange melting around it was a big question mark. Was it the glue stick? Not sure what else it can be.

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6

Re: Did part of my bed melt during a long print?

what do you coat bed with for prints to stick? clean bed then see if it was that. shouldnt leave adhesive for more than a couple prints nor reapply without cleaning down to bed surface fresh again. that can cause lots of issues

Solidoodle 2 with Deluxe kit cover & glass bed with heater. and 2nd board SD2 used not 3rd and alum platform not installed yet still wood. also need cooling fan installed to board. use Repetier Host couple vers. Slic3r also have all free ware STL programs

7

Re: Did part of my bed melt during a long print?

I use the glue stick that came with it. It was a couple of prints prior to the last cleaning and reapplication of glue.

8

Re: Did part of my bed melt during a long print?

The exact same things happened to me, except a much larger area.  Although I have contacted XYZ, and although they have not told me for sure they are sending a new bed, I assume they are.  I have an idea for a solutions however.  I am getting a 3 MM piece of glass, and am going to lay that on the bed on TOP of the broken glass.  The two metal guides that hold it will easily hold an additional 3 MM of glass.  The machine will need to be re-calibrated after installing the glass because it will need to adjust the Z offset to make way for the additional 3 MM.  I will be trying that within the next few days and will let you know how it goes.  Then when XYZ sends me a new bed, I will have a replacement one in case I run into problems and the old one "burns out" or something.

9

Re: Did part of my bed melt during a long print?

Well, I said I would keep you informed.  I got my 3 MM glass, cut to 200X200, went to install it, and its too SMALL!  The bed is actually 210X210.  In inches 8 1/4 fits perfect!  I managed to "Hack" it into place for a test print while I waited fro the glass company to cut me the right size.  I figured I could at least calibrate the bed.
So, I removes the two metal parts that hold the bed on and placed my glass on it, attaching the two metals parts back.  Now, this is important.  I used the thumb screws to LOWER the bed 3-4 MM.  Then I told the printer to print a demo print.  As soon as the extruder moved into place, and it moved the bed up for the final time, I turned off the printer.  Then by manually pulling the extruder around the bed, I calibrated by eye and feel.  When I was satisfied I fired the printer back up, put glue on the bed, sent it a file to print, and watched carefully.  The first part it extrudes on the right side of the bed just to be sure the filament is flowing correctly didn't stick to the bed well.  This leads me to believe that the 3 MM glass doesn't conduct heat as well as I thought it would, however the rest of the print came out fantastic.  Like the best print I have ever gotten from the machine.  Layers were perfectly smooth and even.  It was just incredible.  (I assume its because the touch and eye calibration did a much better job then the built in calibration could ever do.)  So, bottom line, it works!  Very well.  I think the 3 MM glass is a bit thicker then is needed, but needless to say, it works.
So, here is my suggestion to everyone to help protect your print bed from damage.  Call your local glass company (or cut it yourself) and get a 3MM (or try 2 MM if you want) piece of glass cut to 8 1/4 X 8 1/4 inches.  Then take it and install it right over top of the glass that's there.  It does not need to be tempered.  It does not need to be treated to withstand heat.  The bed doesn't heat up fast enough to crack the glass.  Re-calibrate, and print on that.  Then, if something does happen, and you break you glass, you haven't broken the permanent glass that's attached to the element, you just replace your "overglass" you just installed.

10

Re: Did part of my bed melt during a long print?

Sounds like a good plan. In addition, you will find that having 2 pieces of glass will allow you to remove one piece where it will cool much faster and will pop off the glass with very little effort. Putting the 2nd piece of glass down will allow you to do another print without waiting for the bed to cool for print removal.

SD2 Expert stock, ABS fume fan,
XYZ DaVinci 1.0 stock ABS, Simplify3D
QUBD Two-Up PLA, new 3D printed X gantry, Y idler, flex z coupler, extruder mount, E3D Lite

11

Re: Did part of my bed melt during a long print?

Nice SW!

How do you handle the metal plates used for the calibration test? Do they still fit with additional glass up top or do you have to jury rig it?

12

Re: Did part of my bed melt during a long print?

i feel your pain

http://i.imgur.com/ODuJQ2t.jpg

13

Re: Did part of my bed melt during a long print?

No, the metal plates fit fine.  The screws are quite long.  I though that too, but removed one of the screws before I decided to buy glass, and was impressed by how long it was.
However, I cracked the glass too, with the EXACT same print that I cracked the original one with.  I am thinking that the glue is holding the print down very well, and the print is cooling, and contracting faster then the bed, causing it to crack a chip off the glass.  I am going to do some more testing without glue.  I did one print (albeit not nearly as large) with no glue, and it all went well.  I am waiting for some different color filament to come in before I print another, cause I want them in different colors.

I will keep you informed!

jfabritz wrote:

Nice SW!

How do you handle the metal plates used for the calibration test? Do they still fit with additional glass up top or do you have to jury rig it?

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Re: Did part of my bed melt during a long print?

Thats a really bad one.  Mine wasn't that bad, but I think you can still make a cover glass work (provided the head bed still works)
I would give it a shot.  What you got to loose?  The glass companies where I live changed me about $8/ea.  Worth it for a shot if you ask me.

ajwoot wrote:

i feel your pain

http://i.imgur.com/ODuJQ2t.jpg

15 (edited by mathew_orman 2017-01-11 11:41:37)

Re: Did part of my bed melt during a long print?

I had the same problem and now all resolved and explained..
When the head scrapes the glass plastic get molecular bonding to glass...
Bond is strong enough to detach some glass when one tries to remove it by force or even after it is cooled in a freezer i pops off with glass chunks  attached..

Simple solution: make sure your first layer is at least 150 to 200 microns which meas that you must have your glass table leveled and offset on Z correctly