Shielding Cans with Selective Non-conductive Coating

Precision Micro, the Birmingham based specialist manufacturer of bespoke EMI/RFI board level shielding solutions has developed its own dielectric coating process for the inside of shielding cans where the possibility of arcing exists between circuitry and the grounded shielding can. Arcing can occur as a result of turn-on spikes or surges (electromagnetic pulses) caused by external stimuli and can be very damaging to active electronics devices.

The insulative coating can be applied selectively to inside surfaces of the shielding can considered most susceptible to arcing, enabling cans to be designed to fit in with reduced profile requirements favoured increasingly by electronics designers.

The ability to reduce the overall height of a can makes it better able to meet the miniaturisation requirements of modern electronics assemblies and can also improve the attenuation by minimising the linear dimension of apertures which in broad terms governs the shielding efficiency of the shielding can.

Branded MicroSafe this exceptionally even coating is pinhole free and has no detrimental effect on the shielding efficiency of the formed can. Adhesion to the substrate metal (usually nickel silver) is excellent and the upper operational temperature is claimed to be in excess of 260°C.  Selective application of the Micro-Safe coating allows pins and SMT lands or feet to be left bare to maintain the can’s naturally high solderability.

The insulation resistance of the MicroSafe coating, even under high humidity conditions is reported to be greater than 1 x 1011 ohms. It has outstanding adhesion properties and a flammability rating of UL 94 V-0. The coating surface is smooth and non-hygroscopic and SIR testing has been carried out with excellent results.