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Stencil foil life span

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SMTA-Davandran

#84151

Stencil foil life span | 9 January, 2020

Anybody has data for stencil foil life span?

This message was posted via the Electronics Forum @ SMTASMTA

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#84153

Stencil foil life span | 9 January, 2020

Stencil lifespan depends on several factors such as squeegee type, squeegee pressure, handling,and foil thickness to name a few.

There is no magic number. The best judge is your SPI machine if you have one. We typically start thinking about replacement when they start to severely "coin" to the surface of the circuit board and get real shiny spots.

The newer SS alloy stencils are extremely durable if deployed and handled correctly. If I were to guess.. I would estimate tens of thousands of cycles easily.

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#84156

Stencil foil life span | 9 January, 2020

From what I have seen it will be based on thickness, material and usage. Sometimes will be product dependent if the you have a marginal process. We used to change stencils every 2-3weeks for a high runner. Other than that follow Sr.Tech's advice.

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DWL

#84157

Stencil foil life span | 9 January, 2020

2-3 weeks? wow!

I've had stencils last over a decade and only needed replacing because the adhesive holding the mesh dry rotted and crumbled. Of course build volumes were in the order of 50-100 per year.

Just goes to show there is no easy answer for stencil life expectancy.

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#84158

Stencil foil life span | 9 January, 2020

Much like DWL we have multiple stencils that are really quite old (~2003 and still in use) and are perfectly OK. In fact I don't think we've ever worn one out, higher volume designs are far more likely to get a layout change before the stencil gets even a little tired. Either way its enough prints that the cost per PCB per foil is basically insignificant.

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#84164

Stencil foil life span | 10 January, 2020

We changed monthly on lines where we were doing 1500 print cycles+ per day, but on low runners we could use a stencil for 10 years+. As previously mentioned it depends on how you treat it.

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#84166

Stencil foil life span | 10 January, 2020

Yes,

think of 3prints/minute 24 hours. This is about 4000 prints a day. than you have a marginal process, because customer locked design and doesn't want to change anything. So in our case for 70k-100k prints and we had to change them as the performance changed significantly.

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#84171

Stencil foil life span | 11 January, 2020

There's a lot of parameters to consider in defining stencil life cycle. Average squeegee pressure used, in-process cleaning frequency (auto and manual), physical appearance over time, tension reading over time, and so on to decide how many print cycle should be the minimum life cycle of one stencil. Some stencil suppliers claimed that the durability of their stencil can withstand 50K print cycle minimum, but in the end it depends on the treatment of the stencil by SMT house itself that really determine the longevity of said stencil.

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SMTA-Davandran

#84191

Stencil foil life span | 15 January, 2020

At least there are method on detection of stencil replacement before it really fail which can safe line down.

This message was posted via the Electronics Forum @ SMTASMTA

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