what is stencil and how it will help solder?

[liletian]

Hi guys
I heard that stencil can help the solder process. I try to use gerbv to look at files ptc and pts, but they can not be viewed. I am wondering what is stencil and how can it help the solder process?
Thanks a lot

 

[keith1200rs]

The stencil is a thin mask, usually metal, used for applying solder paste to the PCB pads. It isn't often used for home construction but with the increasing difficulty in hand soldering ever smaller devices it is starting to be used for prototyping. You need a reflow oven, but some cheap toasters can be coaxed into providing that service. Have a look at PCB-Pool's web site - they sell a reflow kit. Also Dan Strother's blog (I think that is how it is spelt - try google.)

Keith

 

[Mattylad]

Seethis tutorial for hobby stencilling.

They are using a clear plastic stencil rather than the usual metal one used by industry - but more than adequate for home/small users.

 

[keith1200rs]

Plastic stencils are fine for limited manufacturing runs although PCB-Pool provide free laser cut metal stencils with their prototype PCBs if you request it at the time of ordering. I don't know if any other manufacturers are doing that.

They also have a tutorial on their site about how to use it, I think.

Keith

 

[marce]

Solder Paste Stencils and printing is the most CRITICAL function in the SMD reflow chain, they control the volume of paste for each component pin as well as the solder paste shape etc.
IPC-7525A
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EMS007 The Evolution of Stencil Technology
EMS007 Proof of Design - What To Build And How To Build It Starting With The Stencil Printing Process
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