Print pulls chunks out of glass plate

[thedoble]

I've seen some posts relating to this but never experienced it myself until now.

FYI my Rostock Max v2 has around 16 days print time. Is completely stock other than an e3d v6 lite.

I usually print PLA at 195/60 but lately have needed to run some ABS which I print at 220/90 degrees C.

This would probably be only the 7-8th ABS print I've run on this printer.

[img]http://i.imgur.com/p2UL99g.jpg[/img]
[img]http://i.imgur.com/clZYBMV.jpg[/img]

It's hard to see in the photos but there's a thumb-sized piece of glass carved out of the surface. You can see the shiny section on the print.

I only use glue stick to secure my prints and in this case I left the glass and print to cool before giving it a gentle push to pop it off.

Have I done anything wrong? How do I avoid this going forward?

Thanks

[McSlappy]

Wow I'm impressed it pulled up when it doesn't look like such a large surface area... In multiple places too?

I just assumed it was a freak occurrence when mine did this a year or so ago, but if anyone has some better advice on this I'd love to hear it too!

[thedoble]

Yeah two spots, one about the size of your thumb, and one the size of a 10c piece.

The print wasn't very big, I've done much larger.

Keen to know if anyone has any advice on avoiding this.

I think from now on I will chuck the glass in the freezer after each print so that the plastic pops off on its own. That should reduce the amount of force on the glass. In this case, I let it cool to room temperature (I was out of the house) and then pulled the print off.

[IMBoring25]

To state the obvious, if you have an alternate build surface over the top of your glass, the glass won't come with the print. I've pulled my Kapton up with a print more than once and it's a bit of a nuisance to have to re-do it, but I've never had to replace the glass. The same would, of course, apply to painter's tape, BuildTak, or PEI.

Avoiding the need for a liquid-based adhesion promoter is a nice bonus (and my actual reason for going with Kapton). I generally wind up doing an acetone wipe to clean the Kapton nicely before each non-trivial print, but the surface itself remains serviceable for quite some time as long as nothing goes seriously wrong.

[Eaglezsoar]

What are you using on the glass before printing?

[Polygonhell]

This happens with borosilicate plates, I've seen probably half a dozen people post the same thing, here or on the reprap forum, I don't think it has anything to do with what sort of adhesion promoter was being used, I think it's more likely a small fault in the glass, that weakens an area.

[thedoble]

To state the obvious, if you have an alternate build surface over the top of your glass, the glass won't come with the print.

I might look into PEI for my new plate which I've ordered.

What are you using on the glass before printing?

Just UHU glue stick.

[Eaglezsoar]

It is possible that SeeMeCNC would replace that plate under warranty but you would have to contact them.
I don't know what the policy is now concerning the warranty and the glass but it not hurt to ask them.

[U.S. Water Rockets]

To state the obvious, if you have an alternate build surface over the top of your glass, the glass won't come with the print.

I might look into PEI for my new plate which I've ordered.

What are you using on the glass before printing?

Just UHU glue stick.

I've had 2 borosilicate plates with chips pulled out now. I thought the first one was because I was pulling off the print too hard, or trying to cool it with a small fan to rush the process, so for the second one I would let the print cool off and separate naturally at room temp. After a while the chips just showed back up and I would have to flip the plate over or work around the chips. I just used the purple glue sticks and nothing else.

I am interested in PEI now that I've looked into it. Does someone make a drop in plate replacement for the Rostock Max? Or, do I have to buy a square and cut the circular plate myself?

[Polygonhell]

I don't know of anyone that sells a round cutout PEI, and I found if a pain in the ass to cut. If I was doing it again, I'd probably use my bandsaw, but when I did do it I used a knife.
The only tricky part in installing the PEI sheet is getting the strips of tape on flat in the first place, the plate from amazon is thick enough your unlikely to introduce bubbles.
I have 2 of the round plates here, and have had them since they were first introduced, and a couple of rectangular borosilicate plates I had cut for a different printer, I've used glue sticks, hairspray, abs juice, diluted PVA glue, you name it and never had a chip come out. But as I said this does happen.
I use my PEI surface pretty much exclusively at this point, very occasionally, I'll use something else.

[nitewatchman]

Don't be intimidated by the PEI install. I broke a glass plate a couple of weeks ago forcing me to go to my spare. Both were PEI coated. I ordered in replacement glass, tape and PEI to put a spare back on the shelf and decided to set it back up earlier in the week. The total install took about 20 minutes (less time than the syndicated "Big Bang Theory" episode on in the background).

I use PEI from Amazon or McMAster-Carr (Amazon is usually one side glossy - one side matt and McM-C is both sides glossy), 12" x 12" Tape from Amazon and a Boro Plate from SeeMe. I don't mess with Windex or other "aides" for assistance.

Procedure is simple, first clean the glass thoroughly. I use Acetone, you personal favorite poison will work just fine. Trial fit the tape to the PEI before removing any cover sheets to get and idea of how the alignment looks. Remove the plastic protective sheet from one side of the PEI sheet. Now take a deep breath and start to peel the first tape cover sheet. I peel about 3/4" from one edge parallel to the edge and fold it over on it self. This should leave about a 3/4" band of exposed tape. Holding the exposed tape up off the PEI align the still protected tape with the PEI sheet. Remember removing that protective plastic cover from the PEI? Think about why we did that! Then working from the still covered part to the exposed part of the tape, seal the tape down to the PEI along the 3/4" exposed band.

At this time you should have a tape sheet aligned to the PEI sheet stuck firmly and permanently along the exposed 3/4"edge with the cover sheet folded under the tape between the covered tap and the PEI. You will also likely have an expression on your face that is best described as "What the hell have I gotten myself into?". Now grasp the tape sheet and raise it so the covered area is at an angle of 60 to 90 degrees to the PEI. Grasp the cover sheet, remember the part that we folded under and gently start to pull the sheet from between the tape and the PEI. As you do this with your other hand continually press the tape down from the other side to adhere it to the PEI. Keeping the pressure close to the peel point will minimize any bubbles and eliminate creases or folds. Continue until the tape is completely stuck and you are standing with a loose cover sheet in your right hand and a PEI sheet with tape applied in your left hand. (Reverse hand positions if you are inconveniently "back handed", while this reverse application works best in the Southern Hemisphere, it is adequate in the North). You should not see any bubbles or blisters between the tape and the PEI BUT I should also be wealthy enough to be able to pay someone to do this for me. If you do have a blister, they can sometimes be worked to the edge of the tape or it is acceptable to lightly slit the blister and press the air out.

Now we will basically repeat the operation to attach the PEI to the Glass. Trial fit again and get a good feeling where the PEI will land. Since the PEI is a little smaller than the glass, there will be a small chord of uncovered glass on all four sides. Trust me this is not a problem. After committing this relationship to your ID, proceed with peeling back and folding over the cover sheet from the second side of the tape just like before. Place the PEI sheet on the glass, align using you fond memories of what this once looked like and press the PEI in place sealing it to the glass. Up to this point everything has gone fine, now it likely just dawned on you that this PEI stuff is stiffer than the tape and I can't bend it up the way I did the tape to the peel the cover sheet off! If it hasn't hit you, wait for it - it's coming.

So with the PEI sheet partly stuck, the cover sheet is a little harder to remove. Flex the PEI up by 20 to 30 degrees and grasp the edge of the cover on the PEI/tape that is outside the glass. Gently peel the cover sheet back to remove it from the tape. Work both sides in a seesawing motion to work the cover sheet out, the more you get out the easier it becomes. Lightly press down the PEI to the glass to avoid bubbles working from the stuck to unstuck area. If you work it too aggressively, the PEI will tend to pinch the cover sheet making it a more difficult to pull. Take your time and work both sides of the cover sheet. The definition of a catastrophe here is the tear the cover sheet leaving a bit inside between the PEI and the glass. Never had this happen but I am always watching for it. After the cover sheet is completely pulled out, you should have a square peg trying to fit a round hole. Gently work pressure on the PEI from the center out to assure the tape is stuck to the PEI and the glass. I use my fingers. Do not remove the top protective film yet.

Now to deal with those corners. I have found that the best tool is the back edge (not the sharpened one) of an #11 Xacto Knife. I pull the knife backwards to score the PEI sheet from the back using the edge of the glass as a guide. This should make a scratching sound and peel up a little shaving of material. I will do this 10 or 12 times until I have a nice deep groove. Now pick up the PEI/glass and using you thumbs flex the PEI from the PEI side to the Glass side a time or two, the idea here is not to break it but to put strain in the unscored side. Now flex back the other way and it should pop off nicely along the edge of the glass. The protective film you left in place manages any stray bits that might decide to launch. Repeat three more times and clean up edge with knife, sandpaper, etc. or just leave it - I don't care, not my fingers. Remove the protective film before attempting to use.

Took longer to type this using two fingers than it takes to apply the PEI but then I have done more than 3 or 4 or 5 or 6 times. I use it on my printers, I use it on my R&D printers at work and several friends use it on their printers.

These instructions are fully warrantied under the UCC of the State of Alabama and in the event of difficulty or loss resulting from following said "suggestions", I will cover all damages up to an amount equal to the total amount that you paid me for them.

Happy New Year and I hope this helps!


gary

[IMBoring25]

For both my machines, I've printed the shape of the periphery of the bed (sectioned into pieces and joined, obviously) with a groove down its center at the correct dimensions of the bed. I stretch my tape over this tool and then run an X-Acto knife down the edge of the groove. Discard the excess, peel up the parts that will be used, wet apply, and squeegee. If there's a more painless way, I haven't found it.

[twiggy]

Thanks for the great write up. You are right it took longer to read than to do the install. Went perfectly no bubbles. By they way, don't bother with a bandsaw, just use a good pair of kitchen shears--goes right through it.

Chris