Sublimation press uneven pressuer

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mikic1
Posts: 183
Joined: Tue Nov 15, 2011 11:51 am
Location: sweden

Sublimation press uneven pressuer

Post by mikic1 »

Hi guys,

I was wondering if any of you had similar issues with a vacuum sublimation press, and uneven pressure.

My setup is:
MDF - silicone air seal- heat insulator - heat blanket - 3mm aluminum - graphics and topsheet - top silicon sheet for the vacuum seal

As seen on this picture, the top of the setup has a lot of air bubbles, that do not really give any pressure. This happens when I clamp the press and the silicone sheet on top expands and leaves some air...
Image

the results at 130-140 degrees for 10ish minutes:
Image

I talked to OAC, he suggests a breather could be used on top to help the air escape? Anyone having other helpful hints?
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

you need breather stuff on top!
Tom
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

Btw. friends ha also troubles with similar setup.

I came to two conclusions:

1. on vacuum maybe a nice topplate would help, like 2mm or more alu to create even pressure (calculate the added heatsink!)

2. with this setup you need also a superflat bottom, imho the heating mats are not superflat ... so maybe thicker plate on bottom tooo


Im not sure if i try this setup or a more conventional setup (like t-shirt press) which is more work to build
On the conventional presses you have a special foam on top, so you create even pressure especially with not superflat material... This one i need to find.

Maybe a hybrid version would be the way to go (building like tshirt press but with vacuum to create even pressure on the topplate)
Tom
mikic1
Posts: 183
Joined: Tue Nov 15, 2011 11:51 am
Location: sweden

Post by mikic1 »

Thanks for the input, would be nice to know what kind of foam it is, especially if it breathable like a sponge...
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

I did find the info on some sublim forum .. and lost it again.

It doesnt need to be breathable or not

Think about this (bottom to top)

Baseplate
Heating Mat
Alu Plate
-- sublim print and target material ---
foam
alu plate

this whole stack you pack in the vaccuum bag and voila ... or not ;)

this i meant with hybrid version

The "Not" version would be that you have air trapped with this setup. Then we would be back to the conventional press
Tom
mikic1
Posts: 183
Joined: Tue Nov 15, 2011 11:51 am
Location: sweden

Post by mikic1 »

Yea, although I would like to avoid the top aluminum due to extra heat sink...

but lets see how it goes.

This could be useful
http://www.rollsheetrubber.com/html_l.aspx?id=543
mammuth
Posts: 449
Joined: Tue Oct 28, 2014 3:48 am
Location: somewhere in the alps

Post by mammuth »

Yep, thats it. In the sizes we need not so cheap, for sure :)

I think we work with pretty flat materials (base / topsheet) so it should work when pressed between two plates. And you shouldnt get so much problems with the upper alu. Imho you need to heat just the transfer paper and a little bit of the printing side on the target material.
So the target material acts as heat insulator anyways and the vaporized paint just needs to condensate there. Will depend on the heat and time as well.
Tom
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