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SMT electronics assembly manufacturing forum.


Adhesive Stencils

Verm

#3598

Adhesive Stencils | 10 July, 2000

Does anyone know of a supplier who can manufacture stencils for the deposition of adhesive. The stencils are made from plastic and have underside routing to allow relief for through hole components. I know of only one who can do this DEK's PumpPrint method.

Please advise.

Cheers

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#3599

Re: Adhesive Stencils | 10 July, 2000

George: So, how do keep your stencils "made from plastic and have underside routing to allow relief for through hole components" from building-up static charge during print cycles and handling and then discharging through and damaging the PTH componets on the board?

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#3600

Re: Adhesive Stencils | 11 July, 2000

Dave, George I think we're missing something here, or at least I am. While the plastic in question could possibly be dissipative or non generating, I'm wondering how thick such a stencil would be to clear even the lowest profile PTH component? Can we visualize adhesive mountains? John Thorup

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Verm

#3601

Re: Adhesive Stencils | 11 July, 2000

Dave, the material in question is Acetal. I believe it is anti static. Should there be any charge built up then (hopefully) the charge is dissipated through the frame in which it is housed within the printer. It is an established process within our company and quality results do not indicate any failures due to static discharge.

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Verm

#3602

Re: Adhesive Stencils | 11 July, 2000

John, Dave. The adhesive deposition is on the second pass through the SMT area, the PTH components have previously been fitted during the axial / radial stages of manufacture. The stencil is 2mm thick with a 1.5 mm routing depth. the leads (cut & clinch) do not pretrude enough to cause any problems. Does this help?

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#3603

Re: Adhesive Stencils | 12 July, 2000

John: I agree. We keep out lead stand-off below 60 thou.

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#3604

Re: Adhesive Stencils | 12 July, 2000

George: Interesting. I've found a couple of sources for antistatic Acetal.

OK. To the point: I don't know, but I plan to talk to slective wave solder fixture fabricators. Several are listed in the archives

Good luck

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DEK

#3605

Re: Adhesive Stencils | 13 July, 2000

If you want some information look at the DEK website

http://www.dek.com/adhesives/

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