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Degassing of solid optical clear adhesive using vacuum

Degassing of solid optical clear adhesive using vacuum

(OP)
Hello,

I want to degas the air bubbles underneath the new glass i applied to my phone.
Would pulling 29Hg vacuum do the trick? I have added a picture for clarification.

RE: Degassing of solid optical clear adhesive using vacuum

Once you trap air bubbles it is very difficult to remove them. The trick is to not trap them when initially applying the glass. The proper technique depends on the adhesive and the adherends. There must have been instructions for you to follow.
The typical method of applying a decal is to place a drop of liquid adhesive or solvent at the center and sqeeze it out to the edges so the air is replaced by the flowing fluid.
Vacuum could destroy other parts of your phone.

RE: Degassing of solid optical clear adhesive using vacuum

(OP)
I used a precut piece of solid optical clear adhesive. Applying that without air bubbles seems impossible to me. Do you think i could remove the LCD unit and place that under vacuum?

RE: Degassing of solid optical clear adhesive using vacuum

"Applying that without air bubbles seems impossible to me."
The difference between the correct technique and the wrong technique is very subtle and will seem like magic to the inexperienced. Experience means practice and getting it wrong many times, at first. There is little hope of fixing your bubbles. Start over.
What adhesive are you using and what instructions are given by the manufacturer?
I've worked for 30 years making film adhesives and carbon fiber prepregs (which are thin sheets of tacky material). Trapped air bubbles are an extremely common problem but often cannot be seen. Some solutions involve product design, other involve application technique.

RE: Degassing of solid optical clear adhesive using vacuum

(OP)
Thank you for your feedback

There are no instructions available from the supplier, however there are some video's on youtube on the matter.

http://www.youtube.com/watch?v=ndgBUhYIhaM

In this video they put the entire assembly into the vacuum autoclave. Now i imagine that this would not be necessary if you could apply the new glas without bubbles. However i wonder if one can "fix" the amount of bubbles that i have gotten after my try. But apparently you can use vacuum to remove air bubbles inside the LCD assembly.
What is unclear to me is the amount of vacuum that this industrial vacuum autoclave can pull. Might you know this? Obviously purchasing an industrial autoclave is not an option for me. However i might be able to pull the same vacuum in a somewhat cheaper setting.

Now i do routinely fix these phones. Normally I leave out the OCA but the results would be worth it if it can be done.

RE: Degassing of solid optical clear adhesive using vacuum

Your problem is due to the way you are applying the film adhesive. Pulling a vacuum on the phone is unlikely to remove the air pockets unless the shear strength of the adhesive film is fairly low. You might get better results by using a liquid adhesive and a vacuum.

Autoclaves are chambers that apply elevated pressure. If all you want is to apply a vacuum while bonding your parts, this can be achieved using a simple vacuum bag.

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