High-impact plastics are rapidly replacing metal casings for electronic equipment, especially in military and aerospace applications where weight minimization is a primary design requirement. Also, the “lightening” of industrial products is nowadays a priority throughout manufacturing, for example, to increase the portability of medical devices, or to improve gas mileage in automotive applications.
As well, plastics are less expensive than metal, can be more easily molded or cast into attractive shapes, and allow 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; and they provide no protection against electrostatic discharge, all of which can cause catastrophic electronic failure. This has been a major design challenge for plastic in electronic applications, at least until now.