Electro-Tin/Solderable Platings

Plating Guidelines

Applicable Industry Spec: ASTM B545, CLASS A and CLASS B

When applied to surface mounted (SMT) fasteners, minimum tin thickness on all significant surfaces is .0001 inch meeting ASTM B545, Class A. When applied to all other fasteners, parts minimum tin thickness on all significant surfaces is .0002 inch meeting ASTM B545, Class B. Significant surfaces exclude such features as threads, holes, deep recesses and bases of angles.
All tin is electro-deposited from a matte tin bath.
When applied to SMT parts the tin is applied over nickel which is applied over copper for optimum solderable shelf life.
When applied to base materials with over 5% zinc content copper and nickel barrier layers are used. Although neither layer meets the minimum thickness per ASTM B545, the two layer combination is effective at preventing zinc migration into the tin plating.
Parts are stress relief annealed at 300 °F for 1 hour to deter Tin Whisker Growth per iNEMI recommendations.
A clear preservative coating is applied after electro-tin plating.
Each lot is tested for solderability with lead free solder by the dip and look method.
The parts shall be capable of passing an adhesion test per ASTM B545 Appendix X2.2 and ASTM B571, para. 13.2.

Applicable Industry Spec: MIL-P-81728

The parts shall be capable of passing an adhesion and solderability test per MIL-P-81728.
Typically, electro-solder offered by PEM is .0002″ to minimum of electrodeposited tin-lead plating applied to all significant surfaces. Significant surfaces exclude such features as threads, holes, deep recesses and bases of angles.