Need advice on printing surfaces

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ftdesigns
Posts: 138
Joined: Mon Oct 15, 2012 5:19 pm
Location: ny/nj metro area

Re: Need advice on printing surfaces

Post by ftdesigns » Tue Jul 16, 2013 11:20 pm

You really probably don't want to print raftless. It would work, but you'd have to clean up the bottom because the ABS slurry will be fused to the piece...which also means you may have a color mismatch.
Thanks very much for the info LonV!

The mismatched color on the bottom is a big downside for me, but for certain parts it won't matter.
The fact the whole part is sticking to glass so well is really good. I feel like the glue and perf board worked well because the part warped and pulled up the perf board, so wouldn't work with glass.

Perhaps acetone with hairspray? I haven't used hairspray yet, but it kind of makes sense that it would act as a clear adhesive while the acetone kind of melts the bottom of the part. I wonder...

LonV
Posts: 220
Joined: Thu Nov 15, 2012 11:53 pm
Location: Phoenix, Arizona, USA

Re: Need advice on printing surfaces

Post by LonV » Wed Jul 17, 2013 12:45 am

You could always use a Clear ABS as your slurry...I just use what's around.

I've also had really good luck (and have used it longer than the slurry) with Kapton on glass, and then I use a glue stick on the Kapton (always wipe with Acetone in between prints). The nice thing is the glue stick is water soluble, so if you can just wipe it down or rinse it and the adhesive is gone.

The downside for me is that I'm always ripping the Kapton with my putty knife. :) Also, the Kapton can get bubbles in it after 5ish prints and you can either cut them or redo the tape (which I find a hassle).

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wilsonj
Posts: 569
Joined: Tue Feb 28, 2012 10:26 pm
Location: Australia

Re: Need advice on printing surfaces

Post by wilsonj » Wed Jul 17, 2013 4:46 am

ftdesigns wrote:
You really probably don't want to print raftless. It would work, but you'd have to clean up the bottom because the ABS slurry will be fused to the piece...which also means you may have a color mismatch.
Thanks very much for the info LonV!

The mismatched color on the bottom is a big downside for me, but for certain parts it won't matter.
The fact the whole part is sticking to glass so well is really good. I feel like the glue and perf board worked well because the part warped and pulled up the perf board, so wouldn't work with glass.

Perhaps acetone with hairspray? I haven't used hairspray yet, but it kind of makes sense that it would act as a clear adhesive while the acetone kind of melts the bottom of the part. I wonder...

No colour mismatch if you use clear ABS. I personally use clear nail polish I get from the cheap shops. Works really well.
Regards
Jamie
3DPrinterGear.com.au

LonV
Posts: 220
Joined: Thu Nov 15, 2012 11:53 pm
Location: Phoenix, Arizona, USA

Re: Need advice on printing surfaces

Post by LonV » Wed Jul 17, 2013 6:00 pm

wilsonj wrote:No colour mismatch if you use clear ABS. I personally use clear nail polish I get from the cheap shops. Works really well.
Interesting idea...I'll need to give that a try.

kitutal
Posts: 36
Joined: Sun Jun 17, 2012 4:12 pm

Re: Need advice on printing surfaces

Post by kitutal » Mon Jul 22, 2013 2:54 pm

So glass plates with some sort of adhesive on top seem to work well? any idea where someone could buy these, I've never seen them on sale in local shops.

Neal
Posts: 32
Joined: Sat Oct 06, 2012 2:26 pm

Re: Need advice on printing surfaces

Post by Neal » Mon Jul 22, 2013 5:42 pm

I have used standard window glass that was cut to size at the local hardware store. This works quite well and is very inexpensive. The only downside is that it will eventually crack, probably due to thermal shock. I can get a couple dozen prints out of one piece.

Another option is to buy a piece of "Pyrex" type glass from Octave that they have made up for the UP! It is $19.00 plus shipping. You can see it here:
http://www.octave.com/p1173433164/Boros ... _info.html

I have also used this, until I dropped it on the cement floor and it broke.

doraemon
Posts: 94
Joined: Wed Sep 19, 2012 3:37 am

Re: Need advice on printing surfaces

Post by doraemon » Mon Jul 22, 2013 6:43 pm

Standard window glass shouldn't crack that easily. I think we've used ours here at work for dozens of prints at least and they haven't cracked. Then again, we do have it sitting on MIC6 so maybe that is helping ensure there aren't significant temperature gradients against the glass?

Neal
Posts: 32
Joined: Sat Oct 06, 2012 2:26 pm

Re: Need advice on printing surfaces

Post by Neal » Mon Jul 22, 2013 9:46 pm

I take the glass off, with the print still attached, after just a few minutes. I swap it out for another piece of glass, that is cold, so I can minimize my down time between prints. The glass, with print attached, then cools fairly quickly sitting on my desk. I have no doubt that this accelerated cooling is stressing my glass. If it were to cool while still on the platform it would take much longer and would probably be a more even cooling. This would maximize the life of the glass but the glass is so inexpensive I would rather keep the printer printing then trying to save on the glass.

I suspect that your MIC6 plate is also flatter then my original UP! factory platform. This would cut down on stressing the glass. When I am leveling the platform I use a dial indicator gauge clamped to the extruder head. Once I am as level as practical, the dial indicator always shows that the middle of the platform is approximately .004 to .005" higher then the edges of the platform, both front to rear and left to right. I don't know if the platform came like this or if it has warped over time due to the heater always heating the center of one side of the platform. What ever the cause is, this means that when I clip down the corners of the glass it is adding a small bending stress to it.

roller
Posts: 1622
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Location: Brisbane, Australia

Re: Need advice on printing surfaces

Post by roller » Tue Jul 23, 2013 3:10 am

I use pretty much the same process with swapping hot glass plates (on my reprap though) and I find some glass cracks and some doesn't even when cut from the same pane. Regular glass has some stresses already in it and these are worse in some parts of the sheet than others - I suspect it's which part of the sheet you get.

Anyway, after having a sheet crack and fall out of my hands and down my laptop screen leaving a lovely scratch, I only use borosilicate glass now. It will save my feet if it doesn't save my laptop from further harm.

doraemon
Posts: 94
Joined: Wed Sep 19, 2012 3:37 am

Re: Need advice on printing surfaces

Post by doraemon » Tue Jul 23, 2013 3:16 am

It's probably a combination of the MIC6 being flatter and thermally consistent. Plus, it's thicker than the stock build plate, so it will be stiffer. We swap between 2 panes of Kapton-coated glass, since some parts come off more easily once the glass is cool and we're trying to maximize output on the printer.

I think when I first cut down the MIC6, I checked flatness on a surface plate and it was within a few thou, since it's spec'd as flatness of .015" for a 12" x 12" chunk.

How are you clamping the glass to the plate? We're using some printed clamps, so perhaps it's allowing the glass to "expand" at a different rate from the aluminum? From a thermal standpoint, a build plate made of steel would work better with glass, since they share a similar CTE.

I wonder if it's worth making a ground metal build plate that's polished smooth, then coating it with Kapton? Hmm ...

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