Metal Reinforced 3D Printing

For high tension belts - we can print spring steel wire or other high tensile material into the 3D print. If spring steel is 145 ksi tensile, then if we wanted to quadruple tensile strenght of any plastic from say 5ksi to 20 ksi - we would fill with 14% metal - so we water down the strength of the spring steel from 145 ksi about 7 times to get to about 20000 psi tensile strength.