Using Metal Coating to Improve RP Applications

A continuous goal of rapid prototyping (RP) is to transform itself into a rapid manufacturing (RM) process. As materials improve, new processes are being developed and optimized to further extend the newly improved properties. One such process involves nickel plating stereolithography (SL) parts, which has several advantages, including better mechanical properties than the RP process is capable of generating on its own.

In one documented example, coating parts made of a composite SL resin with nickel resulted in a 30 percent increase in flexural strength, a 100 percent increase in flexural modulus and a 540 percent improvement in impact resistance. In practical terms, the results include a greater strength-to-weight ratio and much higher stiffness than those of many metals and greatly increased chemical resistance. The process also is ideal for improving the abrasion resistance of mechanical parts.

An obvious application for these processes is producing low-volume production parts without having to first manufacture expensive, long leadtime tooling. Other real-world applications include coating prototypes of intake manifolds for automotive engines. Advantages include increased temperature resistance and thermal conductivity, which result in reduced susceptibility to thermal shock because the plating will spread the heat more quickly. In high-speed wind tunnels—such as those used to test aircraft parts—plating will significantly increase the stiffness and carry heat away from the leading edge. In low-speed wind tunnels—such as those used to test automotive parts—increased stiffness also is the main advantage of coating the parts. Another major application is improving the integrity of fans operating at high speeds for electric motors and small engines.

With the growth in applications, it is anticipated that RP will progress steadily into the RM arena. The recent introduction of composite SL materials suggests that a whole new world of opportunity exists, and other applications such as these are only a step away from being developed.