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Masking with hight temp non silicone tape before wave

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#58128

Masking with hight temp non silicone tape before wave | 17 February, 2009

I know this is going to sound rather sad, but we have been using a Capton tape for years that contains silicone to mask large components as they go over the wave, as well as large plated holes on the pcb. It was handed down for years as accepted practice and now, It has just come to my attention that this is not good. I need a acrylic polyimide high temp tape to replace the old capton tape. So far all I can find is "3M-7419" that meets the specifications. It is expensive and is required to be purchased by the case and we are barely getting by and can not afford it. Any ideas for somealternatives they may have discovered? I know we could have finger covers made that would help cover some, and I know we can use the old fashioned mask, but we are dealing with a lot of fiber optic cages that are recessed into the PCB and must be covered to keep from getting flux and solder. I've been in the business a long time (2o years) and feel foolish having to ask for help, but I'm the Sr. Process Engineer now and I have to reach out. All ideas or alternative cheaper parts will be appreciated. Thanks

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#58131

Masking with hight temp non silicone tape before wave | 17 February, 2009

Try: acrylic adhesive Klapton tape [google for a source]

It too is more expensive than the silicone adhesive tape. So, your buyer will keep trying to sneak the cheapo stuff in on you. We had to write a procurement specification and they still wont quit. Guys in receiving are trained and fully alert, well, except Monday mornings when who knows what kind of stuff might slip through.

We like to blame it on purchasing, but more than half the time, it's not their fault. We receive certification from the distributor that it had been manufactured to meet the specifications and after checking with the fabricator, we learn it's silicone based.

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#58132

Masking with hight temp non silicone tape before wave | 17 February, 2009

Hey Roland

How come capton beginning with a 'K' gives an error message?

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#58134

Masking with hight temp non silicone tape before wave | 18 February, 2009

Thanks Dave, I have the correct part number from 3m, but like I said they want to only sell it buy the case, and it's expensive. I was hoping someone might know of a distrubutor that might sell in lesser quanities, or a different brand. It sounds like they may have us over the barrel on this one. Glynn Bernard

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#58139

Masking with hight temp non silicone tape before wave | 18 February, 2009

HI again Dave, I was wondering what kind of problems you were experiencing with the silicone tape that led you believe that it wasn't the correct tape and question the manufacturer? Were there more failures and solder issues ? Thanks

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#58144

Masking with hight temp non silicone tape before wave | 18 February, 2009

Glynn We allow no silicone in our shop, because it ruins solderability.

For more look here: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=47025

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#58145

Masking with hight temp non silicone tape before wave | 18 February, 2009

3M and/or Dupont make it expensive.

Try => "acrylic adhesive" "high temperature" tape

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