Inspecting a new stencil

FYI, Here are the steps in which we take to get approval. The stencil gerber layer needs final approval through our Engineering dept. What they do is send in a gerber layer from the stencil house and lays it over the current solder paste layer and verifies it will match within thier gerber viewer. Once that is proven than the stencil house can manufacturer the stencil and send out. Now as for when it gets into house we dont open the package almost until the job gets ready to run down the line. We have had maybe a handful of stencils in past 5 years that maybe had an issue and we had to due next day delievery. It could have been a customer solder paste layer issue or even a mistake an engineer didnt even catch.

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Print material through stencil onto Plexi-glass and place Plexi onto your board. Sure, it may cause a little clean up but this where the metal meets the meat. Don't worry about ESD cause you have no component on the board yet (sorry Quality guys - save your dance for someone else), or wear a anti-static, no-lead, SPC shmock.

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Print paste through the new stencil with a piece of mylar [or other clear plastic sheet about the thickness of paper] between the board and the stencil. Dispose of the mylar according to local practice after confirming proper aperturation of the stencil.

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Most stencil manufacturers use an automated stencil inspection system like our StencilScan AOI that compares the Gerber data directly to the stencil image. We provide the StencilScan AOI system to end users that wish to guarantee stencil / screen and board accuracy and/or cleanliness prior to production. The system can also create Gerber data if the file is lost or damaged. Here is the product info: http://www.smartsonic.com/AOI-StencilScan.pdf

Bill Schreiber Smart Sonic Corporation

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Reading the original post.. Floyd, do you remember the old overhead projectors back before we had the new fancy video projectors? Just get a clear sheet of that plastic and print your outline on that. Put that sheet over the stencil and presto, you can see the ones that got missed.

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An experienced stencil designer suppose to check gerber data before making stencil it take 5 minutes to do this easily in computer after that analyze components if there's any critical parts in order to modify the aperture at USA STENCILS INC we have to do this for every single stencil.

Feel free to contact me at Incoming@usastencils.com

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