PCB Material

We have made no changes to our PCBs for pbfree.

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TM,

When picking a material for your lead free assembly you need to think about a couple of things,

The standard Material in the US that is being used is running 140 - 170 tg. material. But for lead free assembly you need to focus on is Decomp temp (TD). or at what temp does this material start to de-lam. With lead free assembly especially during Wave solder the temps will have to be higher than normal Lead processing which can put this type a material at its upper limits and open the chance for Delaming.

The 140 - 170 tg material has a decomp under 288 C. this is the temp at which it will delam, but it will start to degrade at around 250 c.

The newer material is made with differnent Resins to handle the temps higher and longer before degrading.

We currently run ISOLA IS410 & Polyclad 370 Turbo HR. but the IS410 is our Standard material for lead free. it has a TG of 180 and a Decomp of 350 c. the decomp is much higher than the older material.

Pricing difference between FR406 170 tg. & IS410 180 tg. material is around 10%.

I would not suggest running 170 tg material for lead free assembly unless your boards do not have to go through Wave solder. the Wave solder area is where this product will be stressed the most.

Hope this helps.

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In addition to the response from Board House... You WILL see delamination at lead-free temp even during reflow.. more often than not.... sometime manufacturer's try to get aways with it by pre-baking the board to remove moisture..but I think one has to go for high Td boards..

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