How to enhance the shielding of HMI plastic housings?

To enhance the shielding effectiveness of HMI plastic housings, surface metallization or the addition of internal conductive materials is typically employed. Surface metallization includes vacuum aluminum plating, electroless copper/nickel plating, and arc-sprayed zinc, forming a continuous conductive metal layer on the plastic surface. This method offers high shielding effectiveness, but attention must be paid to the continuity of the plating at housing seams and snap-fit points, as well as the wear and corrosion resistance of the plating. Another method involves incorporating conductive fillers, such as metal fibers, carbon fibers, or conductive carbon powder, into the plastic raw material to create conductive plastic. This method achieves overall shielding without the risk of plating peeling off, but may affect the mechanical strength and appearance of the plastic.

Regardless of the method used, the electrical connections between different parts of the housing need to be addressed, typically by designing conductive pads or metal contact plates at the joints. For internal circuit boards, reliable connection to the conductive layer of the housing via metal brackets, conductive screws, or spring clips is required to provide a grounding reference. The display window still needs separate treatment, using a shielded window connected to its surrounding conductive housing. The design must comprehensively consider shielding effectiveness requirements, cost, and manufacturing processes when selecting a solution. Eintech offers consultation on a variety of conductive plastics and surface treatment solutions, as well as matching grounding connection components to help achieve effective shielding of plastic housings.