Application of laser joining process for elimination of stair steps in steel laminate tooling

Laminate tooling is a relatively fast and simple method of making large metal tools directly for various moulding processes in the rapid prototyping and manufacturing field. Metal sheets are usually cut, stacked, aligned and joined. In most cases, lasers are used only for the cutting of steel sheets in laminate tooling, but in this study, the use of the laser was expanded for improved laminate tooling. First, the laser was applied to eliminate the stair steps of steel laminates by filling them with molten filler metals. Then application of hard particles to molten filler metals for improved surface hardness of laminate tools was investigated. To achieve this goal, a CO₂ laser system composed of a CO₂ laser, a five-axis CNC table, an automatic feeding equipment of filler metal and flux and a personal computer was developed. Various experiments on filling stair steps and hardening were performed and the results were verified and estimated.