Hard Gold Plating?

Hard Electrolytic Gold consists of a layer of gold plated over a barrier coat of nickel. Usually its applied to edge connector fingers and keypads on PCB.

The typical minimum values for fingers are 30 μin gold over 100 μin nickel for standard Class 2 , and  50 μin gold over 100 μin nickel for Class 3.

Hard gold is not generally applied to solder-able areas, because of its high cost and its relatively poor solder-ability. The maximum thickness that IPC considers to be solder-able is 17.8 μin, so if this type of gold must be used on surfaces to be soldered, the recommended nominal thickness should be about 5-10 μin.

Advantages:

  • Hard & strong Surface
  • Lead free
  • Long Shelf Life

Disadvantages:

  • Expensive
  • Extra Processing / Labor Intensive
  • Use of Resist / Tape
  • Plating / Bus Bars required
  • Hard to apply with Other Surface Finishes
  • Etching Undercut can Lead to Slivering / Flaking

 

A few design rules are required for gold fingers / edge connectors.

  • No PTH’s are allowed in the plated area
  • No solder mask or silkscreening can be present in the plated area
  • For penalization, always place gold fingers facing outward from the panel center
  • Connect all gold fingers with a 0.008” conductor trace at the edge to allow for manufacturing
  • Features can be placed on one or both sides to a depth of 25mm from the outside edge

 

To get your quote with Hard gold plating , click here.