High-impact plastics are rapidly replacing metal casings for electronic equipment, especially in medical, military, and aerospace applications where weight minimization is one of the primary design objectives. Also, the “lightening” of industrial products is nowadays a priority throughout manufacturing. Plastics are the material of choice because they’re less expensive than metal, can be easily molded or cast into attractive shapes, and allow for more “form & function” design flexibility for engineers.
But for all their relative virtues over metal, plastics are nonetheless completely pervious to EMI, RFI, and ESD interference, all of which can cause catastrophic electronic failure. This has been a major design challenge for plastic in electronic applications, at least until now.