Optimization of a continuous hot embossing process for fabrication of micropyramid structures in thermoplastic sheets

Reported is the manufacture and optimization of inverted micropyramid cavity structures into thermoplastic sheets using roll-to-roll (R2R) embossing. To manufacture the master, an ultraprecision diamond machining method was applied to create seamless surface structures into a copper-coated hot embossing roller. Using the hot embossing process, the roller features were successfully transferred to 2 mm thick polymethyl methacrylate (PMMA) sheets. Optimization of the R2R control process variables was conducted using Taguchi's numerical methods, which showed the importance of the roller temperature for a successful pattern transfer. The work presents a novel fabrication technique that allows microstructures to be manufactured into thick PMMA sheets in a continuous process.