Printing ABS directly on glass

[pleppik]

I've been experimenting with printing directly onto a glass plate as the build surface using ABS plastic.

Normally ABS won't adhere well enough to glass to make this work, but I've found that if I first paint the glass with a thin layer of ABS dissolved in acetone (about 2 parts acetone for 1 part ABS) I get really good results.The model adheres very well to the prepared surface while printing, but pops off easily and cleanly once done.

Advantages:

• Easier to remove the model than from Kapton, but still excellent adhesion while printing. To remove the model, just slide a knife blade under the model and it will pop right off. No need to worry about damaging the surface.
• Easier cleanup than either Kapton or perfboard: just scrape the glass with a blade, and paint more of the ABS/acetone on for the next print
• Glass surface won't bend or warp like the perfboard

Let me know what you think of this technique.

[wilsonj]

I tried this also, but I found it pulled off the glass when trying to print larger items due to warping. Great for small parts though.

I would be interested to see if frosted glass might work a little better ? Haven't got any handy though...

[pleppik]

I tried this also, but I found it pulled off the glass when trying to print larger items due to warping. Great for small parts though.

I would be interested to see if frosted glass might work a little better ? Haven't got any handy though...

Interesting. I've printed some pretty big models this way without any lifting, but I haven't fully explored the envelope yet.

I wonder if it might be sensitive to the thickness of the ABS film, or the exact ABS/acetone mixture. The mix I've been using is thinner than what most people prepare for use as ABS glue.

I should make a model for lifting/warping stress testing. Something with sharp corners and a large aspect ratio is probably the worst-case scenario.

[eyUP]

I've printed some pretty big models this way without any lifting

I'm having issues with large models lifting off perf board so might give the glass + abs glue a try.
Did you still have the table heater on when printing on glass by the way ?

I should make a model for lifting/warping stress testing

I've attached my test piece here, its only 6mm thick so dosn't take too long to print. About halfway through though, it will always lift in the corners.
I'd be interested to know if anyone can print this without warping.

Cheers,

[pleppik]

I've printed some pretty big models this way without any lifting

I'm having issues with large models lifting off perf board so might give the glass + abs glue a try.
Did you still have the table heater on when printing on glass by the way ?

Yes, I give the platform several minutes to heat up. I think this is important to getting good adhesion because it reduces the thermal stress as the plastic cools.

When the print is done and the glass cools you can hear it "ping" as the plastic shrinks and breaks its bond with the glass.

[Gilius]

I've tried this too with great results. I've switched completely from perfboard to glass now. The only problem is that I need large clamps to hold the thick glass in place.

[CarryTheWhat]

Awesome!! Do you have to re-apply anything to the glass (acetone, or acetone + ABS)? If so, how often?

[pleppik]

Awesome!! Do you have to re-apply anything to the glass (acetone, or acetone + ABS)? If so, how often?

I scrape the glass with a single-edged razor blade after each print, then reapply a thin acetone+ABS mixture.

That gives a thin, almost transparent, coating of ABS on the glass. Hot ABS doesn't adhere well to glass, but it will adhere to other ABS.

So you're printing onto a layer of ABS which is only weakly bonded to the glass. When the print cools, it usually pops right off the glass plate (from the stress of the shrinkage) but stays stuck as long as the glass remains hot.

[wilsonj]

I've printed some pretty big models this way without any lifting

I'm having issues with large models lifting off perf board so might give the glass + abs glue a try.
Did you still have the table heater on when printing on glass by the way ?

Yes, I give the platform several minutes to heat up. I think this is important to getting good adhesion because it reduces the thermal stress as the plastic cools.

When the print is done and the glass cools you can hear it "ping" as the plastic shrinks and breaks its bond with the glass.

I tried the test model a few times with some rather disastrous results. Finally got it pretty good though. Still a very slight upturn on a couple corners, but I put that down to not waiting long enough for things to warm up properly.

I printed it raftless at .3 res, solid settings and normal speed.



showing along edge.


other edge.

[eyUP]

I knew it could be done! I did actually get some better results with the perf board, still using a raft, after a proper clean up with acetone and a good bed warm up...but still finding the stresses during build will pull the model off the top bit of the raft (the interface layer ?) - even though the raft was stuck solid to the board.

I'm thinking that this type of model is not really suited for 3D printing - I've even seen the same thing happen on an HP Dimension (Stratasys)
The test part I posted was based on a student's design that just wouldn't print, in the end we decided it should be manufactured differently (eg, milled, drilled or lasered out of solid plastic)
Like someone else has said, successful 3D printing is not just how good the machine is, but about knowing the limitations of the process and designing with those in mind.