LCD Heat Seal Coming Off Suggestions

Thread Starter

PIC-User

Joined Sep 25, 2015
52
Hi. We assemble many of these boards and sometimes the heat seal connector would come off after we send it to the users. Is there a way (glue, tape, ...) to make this heat seal connection more stable and durable? Any suggestions will be greatly appreciated. Please, see the picture below. Thanks.

LCD-Heat-Seal-01.jpg
 

Delta Prime

Joined Nov 15, 2019
1,030
Hello there! :) Place transparent silicone rubber (like the type found on cell phones that cover the membrane switches) on top of the heat sealed conductors.
On top of that, place a thin silicone pad in between the transparent silicone rubber and a large chisel tip soldering iron set to 400° Fahrenheit or less, apply pressure and that's it. It's all about technique.
 
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Thread Starter

PIC-User

Joined Sep 25, 2015
52
Hello there! :) Place transparent silicone rubber (like the type found on cell phones that cover the membrane switches) on top of the heat sealed conductors.
On top of that, place a thin silicone pad in between the transparent silicone rubber and a large chisel tip soldering iron set to 400° Fahrenheit or less, apply pressure and that's it. It's all about technique.
Thanks. I did a google search for "transparent silicone rubber" and "thin silicone pad" and got tons of results. Would you mind been more specific, so I can buy these things? Thanks.
 

Thread Starter

PIC-User

Joined Sep 25, 2015
52
LesJones, thanks. I have read that applying Kapton® Tapes on top of the connection also helps. They come with a silicon adhesive and can withstand high temperatures.
 

Delta Prime

Joined Nov 15, 2019
1,030
You can make it yourself!
Clear silicone RTV
(Room Temperature Vulcanized)
You can find that at home improvement stores.
Teflon sheets or a teflon cutting board or anything else you can think of that's made of teflon so the silicone will not stick to it. Think of making a sandwich the two sheets are two pieces of bread. You get some flat washers whatever thickness you like think of them as sliced pickles place them on the four corners of the bread. And squeeze the RTV like mustard apply liberally, sprinkle distilled water and cover with the other piece of silicone sheet the other piece of bread get a dinner plate and cover for weight apply pressure. Distilled water will make the RTV cure evenly and faster. Cut to size after 12 to 24 hours depends how thick you make it.
The thin silicone pad is the type used when you buy a new soldering iron so you can replace soldering tips while they are hot. And follow the procedure
Post#2. Works every time for pennies on a dollar.
 
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Thread Starter

PIC-User

Joined Sep 25, 2015
52
Delta prime, do you like the Kapton® Tapes solution? It seems that many people use it, when I did a search in Google.
 

Delta Prime

Joined Nov 15, 2019
1,030
Well you see. The original heat seal contains conductive adhesive that makes the electrical contact. therefore by applying tape over the heat seal does nothing as far as repairing the electrical contact connection is concerned. By applying the tape while assembling the unit will do nothing as far as reinforcing the electrical contact. Then when that unit returns back from the customer with the applied tape you'll be unable to repair the unit. I know time is money. I presume you have RMA protocols (Return Merchandise Authorization). You're going to wind up with the big box of unserviceable merchandise.
 
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