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Making a high pressure vacuum chamber
No_Shorty:
Hey, so I'm not sure if anyone here has the relevant experience or knowledge to answer this but fingers crossed!:
I am attempting to find a high pressure vacuum chamber for OCA film or maybe just LOCA glue. I am guessing the latter needs a lower vacuum as it is liquid, but just a guess.
I am looking to use this 'stretched bar' LCD in a project:
The manufacturer 'WiseCoCo' will of course sell this item with the LCD already bonded to the glass touch panel. The problem with this is that they seem to be doing this by hand/without a 'jig' - and the alignment is VERY poor. They are the only supplier of this panel and I am wanting to use them for a project which I may sell a few of that I would have the body CNCd out of aluminium. As such I need good alignment.
I could try to see if WiseCoCo would use a jig I manufacture myself... but given the numbers I would be ordering (less than 10) - I think it might be a struggle to overcome the distance/language barrier. It's still an option but I have leant toward aligning and bonding the screens myself.
I have done this once with LOCA, but its suuuper messy squeezing all the bubbles out and my first application seemed to cure the glue in a weird way, leaving visible smudges.
I would love to be able to try out OCA film, which is the standard way of bonding these screens now. The problem being you need an 'autoclave' - or vacuum chamber with a recommended pressure of 6 bar. This seems to be rather a lot higher than any of the 'pressure cooker' DIY builds you might find on the web.
I was trying to find a 'plug and play' solution like this: https://www.sznasan.com/shop/lcd-repair-machine/na-b3max/
But unfortunately they are really designed for phones - so the capacity of their 'cavity' is too small. I double checked with NASAN and they confirmed it was only 325mm.
I can't find anything remotely affordable (or a sensible size) that is capable.
So this has all lead me to wondering if I can make something myself. I am aware that 6 bar is a lot of pressure and the realistic answer to this might just be no. But the idea I had was as follows:
To use 3 pieces of Acrylic, 30mm in depth. The centre piece I would cut a hole big enough to fit my screen. I would then seal these to one another - not sure what sealant, maybe just silicone? I would then mount valves to the top piece, near an edge.
I am however unsure if the acrylic could take this kind of pressure, or if I would be able to effectively attach valves that would not leak at these pressures, or if the sealant between the acrylic would leak at this pressure.
If 6 bar is going to be unachievable for a DIY solution, what kind of pressures do you think I might be able to achieve?
jonovid:
high pressure vacuum chamber :-// the contradiction ;D
Kleinstein:
Pressureized air can be quite dangerous. Acrylic is relatively brittle and not a suitable material at this size.
Even just vaccum has some danger from an implosion, accerating the parts in and than having parts bounce back.
If ever possible avoid brittle material, so that failure would be more gradual leakage and not an explosion.
The forces are quite high even at moderate pressure and the construction with flat sides and corners would have local stress concentrations that add to the difficulties. The suitable material would be more like relatively thick steel, especially around seals / openings.
So this does not look like a sensible DIY project.
jpanhalt:
I agree with prior comments on the dangers of pressure. If in doubt, look at how ruggedly a medical steam sterilizer/autoclave is constructed. Typical conditions are 121°C and 15# above ambient. Six bar is a lot more.
wraper:
LOCA doesn't need vacuum chamber. The problem is how to avoid glue getting inside of LCD on the edges and screwing up light diffuser.
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