Heated Bed Advice

That was probably me.

I've had really truly fantastic results with the sanded or blasted borosilicate glass, with a very thin coating of acetone/abs wiped over the surface.100-110C glass temperature (confirmed by multiple means, since everybody seems to be doubting my temperature accuracy)

I have not had a single part warp since I started to do it this way. Even things which would lift the kapton tape off my aluminum build surface in the past. I'm sure it has limits, but they seem to be further out than anything else currently in use (for abs)

I'm finally pretty confident in the why it works/how to reproduce it.

First, the type of glass. Borosilicate glass has a very small coefficient of thermal expansion. Because of this, it is well suited to take the temperature required for an ABS heated bed. As an added bonus, as the abs part cools, the part pops off the build surface (it shrinks much faster than the glass, and creates enormous stress at the build surface.)

Second, the glass surface finish. Plain glass is pretty boring, and completely 'flat' for all practical purposes. Heavy sanding or light abrasive blasting creates a surface with substantially more surface area. The surface roughness/area gives the plastic something to grip.

Thirdly, because abs is so viscous, it cannot efficiently spread into all the tiny craters/scratches created on the surface. By using very diluted abs in acetone, a thin layer of plastic can be completely adhered to the rough surface below.

I'll have two bots at Maker Faire in NY next weekend, if anybody wants to check out the build surface there.

brnrd Wrote:
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> Someone reported having success with printing ABS
> on sanded glass coated with ABS in acetone on
> another thread. I tried this on plain glass and
> although small parts stuck well, large parts
> peeled off at the corners resulting in warping.

Why so much effort to print on raw glass when PET tape works so well?

Heated PET and Kapton tape on aluminum does work very well. If all you print are small parts, like the original mendel parts, then it would be good enough. It also works even for large parts but it doesn't last as long. i just recently printed an 80mmx100mmx85mm hollow box successfully on heated Kapton tape (2" wide) while my Mendel is inside a large carboard shipping box so that the inside temperature is 40-50C. The problem is that the tape still does peel a little bit at the corners resulting in bubbles. I can press most of the bubbles out but not completely. Small ones are left behind and because the tape shifts, wrinkles and folds are hard to avoid. Eventually, the bottom surface of printed parts show the defects in the kapton tape. And, after a while, you have to replace the tape. If glass works without the need for tape, it would not have this problem. I've found that painting ABS in acetone is much easier than applying tape without bubbles.

Personal preference, availability of consumable materials, aesthetics.

Mostly availability of materials, though. Acetone is found in almost every hardware store in the US, and scrap abs is a byproduct of the printer. Application is simply wiping the surface with a little of the mix on a paper towel.

Saw it at Makerfaire and it looks like it performs amazingly well!

Any advice on how to go about getting borosilicate glass sand blasted or heavily sanded? It looks like sheets of the glass are easily available on McMaster (http://www.mcmaster.com/#8476K161) but would one be able to get the required surface finish by simply taking some sandpaper to it?

Sandpaper sorta worked, but took forever and was not ideal. If you know somebody who does body work they usually have a sand blaster for cleaning rust off. I have friend who etches art glass, but I also bought a $10 Harbor Freight hand blaster which worked well enough.

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www.Fablicator.com

Are there any YouTube movies of printers using sandblasted glass beds?
I'd like to see some. My friend has a sandblaster, I'd like to see how it works.

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__________________________________________________________________________
"I like to be, what I like to see, in you and me.
I am the Stallion, Mang."

ISTAR Scope Club

I think I'm the first and only so far.

Not sure if a YouTube video would help. It looks exactly like printing PLA on a heated smooth glass bed.

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www.Fablicator.com

I just moved from Kapton to PET and I'm seeing much better results. PET is stiffer than Kapton, so even if there are small bubbles they don't seem to distort the tape much. Also nophead has reported that if you wipe PET with acetone it brings back its stickyness. I haven't tried that yet though, because I haven't been working on PET that long.

I do seem to have to get PET hotter than Kapton though and I have to mash the first layer a bit more. Kapton worked at 100C and seemed to stick best if there was a full layer height between the nozzle and the bed, PET doesn't seem to stick until I get it to 110C and seems to work better if the first layer gets slightly squashed.

Andrew Diehl Wrote:
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> I think I'm the first and only so far.
>
> Not sure if a YouTube video would help. It looks
> exactly like printing PLA on a heated smooth glass
> bed.


Is the Fablicator you?
Are the pics yours, the ones on the frosted looking glass beds?

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__________________________________________________________________________
"I like to be, what I like to see, in you and me.
I am the Stallion, Mang."

ISTAR Scope Club

If you get warping with the heated bed, try some of the following:

1. Lower your print speed by half. This reduces pre-stress of the filament being laid down.
2. bring the nozzle slightly closer to the HBP on the first layer. You may find that one side of the bed has a greater tendency to peel. Might need tighter leveling.
3. Increase the fill %. This helps keep the whole part warmer, as opposed to having a whole lot of air in there.
4. Clean the HBP surface with isopropyl alcohol with a concentration of 70%-90%. It is a much better cleaning treatment than acetone. I'm not talking about ABS dissolved in acetone, only using acetone vs alcohol as a cleaner.

Yes, the Fablicator is me ( Or I should say mine

I assume the pics are mine, I'm not entirely sure which ones you are referring to though. You mean like this?

[lh5.googleusercontent.com]

BoriSpider Wrote:
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> Andrew Diehl Wrote:
> --------------------------------------------------
> -----
> > I think I'm the first and only so far.
> >
> > Not sure if a YouTube video would help. It
> looks
> > exactly like printing PLA on a heated smooth
> glass
> > bed.
>
>
> Is the Fablicator you?
> Are the pics yours, the ones on the frosted
> looking glass beds?

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www.Fablicator.com

Quote
Andrew
You mean like this?

Yes.
I wanted to see it in action, tnx.

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__________________________________________________________________________
"I like to be, what I like to see, in you and me.
I am the Stallion, Mang."

ISTAR Scope Club

Finally took a good video of a print start.

[www.youtube.com]

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www.Fablicator.com

Nice Video. tnx.

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__________________________________________________________________________
"I like to be, what I like to see, in you and me.
I am the Stallion, Mang."

ISTAR Scope Club