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Inspecting a new stencil

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#53656

Inspecting a new stencil | 15 February, 2008

Currently when we get a new screen, we inspect it by holding a pcb or artwork under it and confirming that there are pads underneath all of the holes. The flaw with this approach is that if there are pads on the board with no corresponding hole in the screen we don't catch it. Would anyone be able to suggest a better technique. Thanks.

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#53659

Inspecting a new stencil | 15 February, 2008

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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#53664

Inspecting a new stencil | 15 February, 2008

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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#53665

Inspecting a new stencil | 15 February, 2008

KRIKIES me lady Chunks. That sounds messier than me swamp!

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#53683

Inspecting a new stencil | 18 February, 2008

We do like Chunks says only a little bit different. Our stencil supplier e-mails us a "confirmation PDF" before processing any order. If it's a simple board, I just make sure all the apertures are there by comparing to board. If it's got a ton of apertures, I request the data they will be using for stencil manufacture, print it 1:1 on a transparency and overlay it on the board. Never had much trouble.

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#53687

Inspecting a new stencil | 18 February, 2008

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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PR

#53689

Inspecting a new stencil | 18 February, 2008

Why not just print a board? You have a spare board for your profile right? When you are done you have a working program and you know if the stencil is correct.

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#53690

Inspecting a new stencil | 18 February, 2008

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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#53741

Inspecting a new stencil | 20 February, 2008

We are in a situation where our parent company sends us stencils from Japan, but the Gerber is not sent. When we need a replacement stencil, we need to wait for Japan to send it. Can your stencilscan system reverse engineer the stencil and generate the Gerber?

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#53742

Inspecting a new stencil | 20 February, 2008

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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#53747

Inspecting a new stencil | 20 February, 2008

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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#53799

Inspecting a new stencil | 25 February, 2008

Hello CarlN,

Yes, StencilScan can reverse engineer a stencil, screen or a board. We just take a high resolution scan of the stencil/screen/board and the software does the rest. Another cool feature is the Assembly Module option for producing assembly programs and process documentation for Pick and Place, Insertion, Test, Inspection and Dispensing machines. There is more info at: http://www.smartsonic.com/index3.html or call me at +1-818-610-7900

Bill Schreiber Smart Sonic Corporation Bill@SmartSonic.com

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#53805

Inspecting a new stencil | 25 February, 2008

zEnough with the sales pitches boys. Try me at Stencilsareus...right next to the Legos...

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#53807

Inspecting a new stencil | 26 February, 2008

Bill,

Is your system the ScanCad system?

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