Glass-reinforced polycarbonate is effective in designs where metals, particularly die-cast aluminum and zinc, are commonly used. The addition of glass fibers to polycarbonate increases tensile strength, stiffness, compressive strength, and lower the thermal expansion coefficient. The greater the amount of glass fiber added to the polycarbonate, the greater the effect on each property will be. The coefficient of thermal expansion is reduced by nearly 75%, thus equaling that of some metals. While glass-reinforced has less impact strength than standard grades, it is still tougher and more impact resistant than most other plastics and die cast aluminum.Lexan® 3412R is a ?20% glass-reinforced polycarbonate with higher temperature and tensile properties than the unfilled Polycarbonate. Typical property characteristics include superior impact strength, outstanding mechanical strength and stiffness, excellent dimensional stability, and good machinability.