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Plating thickness

blnorman

#30084

Plating thickness | 17 August, 2004

We have parts that have electroplated tin over nickel. The mfg. assures us the minimum thickness of the tin is 5 microns. Cross sections have shown many instances of 1 micron and pits that go down to the nickel barrier layer. A request for thicker tin plating has reduced our production problems, but not eliminated them. Is there a maximum thickness for the tin? Is there a point that thicker tin causes new problems?

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#30089

Plating thickness | 17 August, 2004

First, we'd like to see your supplier's minimum Sn thickness to be increased to 10um. Look here for support of this position: http://www.psma.com/HTML/FILES/forums/leadfree/hp_ext_pos_sn_for_pbfree.pdf

Second, increasing the thickness of tin: * Raises the liquidous temperature * Increases the potential for tin whiskering

We do NOT believe that the component industry understands the issues of tin whiskering, nor do we believe matte tin to be the cure-all the some espouse it to be.

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huib

#30585

Plating thickness | 17 September, 2004

We know from experiments that the structure of Sn can be manipulatedby means revese pulse-plating. This means alayer with less pits and thus a lower mminimum thickness is needed.

www.ppcs.nu

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