Rapid Laminated Tooling by a Brazing and Soldering Process

Abstract

Laminated tooling is a relatively fast and simple method to make metal tools directly for injection molding or resin transfer molding in the rapid prototyping field. Metal sheets are usually cut, stacked, aligned, and joined. Joining of metal sheets is usually accomplished by brazing or soldering. In the joining process, all the metal sheet layers should be rigidly joined, and thus heat should be applied to the whole volume of the laminate. Therefore, furnace brazing or diffusion bonding processes are considered suitable in laminated tooling. In this study, a rapid laminated tooling system composed of a CO 2 laser, a furnace, and a high-speed milling machine was developed. From the three-dimensional information of a product, slicing into two-dimensional contours was performed and low-carbon steel sheets were cut with the CO2 laser along the paths that were created from the slicing results. The metal sheets were joined by furnace brazing and by dip soldering. Furnace brazing was for relatively high-temperature tooling processes such as injection molding, and dip soldering was for low-temperature tooling processes such as reactive injection molding (RIM). Dip soldering was introduced as a new, simple, and fast joining process of steel laminates. In both joining methods, wetting experiments were performed to ensure the optimal values of the process parameters. Finally, laminate tools were machined with a high-speed milling machine to improve the surface quality.