Finite element analysis of PMMA pattern formation during hot embossing process

Hot embossing process for thermoplastic polymers is one of the manufacturing technologies for microfluidics and optical components. It combines both micro-scale resolution and high throughput. This is a thermal process where a rigid stamp is pressed onto a polymer substrate so that micro-sized features or patterns can be replicated. PolyMethyl-MethAcrylate (PMMA) is one of the important engineering materials for this process; however, its nonlinear relationship between temperature and elastic-plastic behaviour, until now, has not been very well understood. This paper explores the development and use of finite element simulations to study how PMMA substrate would behave during hot embossing. This is achieved by converting stress-strain-temperature experimental data points into a mathematical form, matrix representation, without losing any salient behaviours of the PMMA material. The simulation results showed the flow behaviour of PMMA inside the mould during hot embossing process. This may assist future improvement of manufacturing quality and production throughput. Hot embossing experiments were also conducted and the results obtained were compared with the simulated ones. Although there was discrepancy between the two results, the current work laid path for future development and improvement.