Fabrication of moulds and dies using precision laser micromachining and micromilling technologies

Abstract

This paper presents results obtained from our studies on the 3D laser micromachining and micromilling technologies. Specific examples of micro moulds and dies, fabricated using these techniques, are presented. The layer-by-layer material removal for 3D precision laser micromachining was proposed and the required process parameters were identified. Specifically, the process parameters, such as overlap between grooves and number of passes per layer, were investigated. The results were then applied to fabricate a "Cross Sign" die with overall dimensions of 2.5x2.5 mm and a wall width of 50 μm in mild steel A20 material. The finished micro die had a surface roughness of < 0.35 μm and contour geometric errors within +/-2 μm. For comparison pur-pose, the same "Cross Sign" microdie was fabricated using the micromilling process from brass and replicated on PMMA through the hot embossing process. Geometric errors within +/-1 μm and a surface roughness inside the rectangular channels of 9.9 nm were achieved. The paper discusses challenges met during fabrication of the dies along with a comparative analysis of the geometric quality.