# Numerical Simulation of Mold Filling of Polymeric Materials with Friction Effect during Hot Embossing Process at Micro Scale

## TL;DR

This paper studies how to improve the filling of micro cavities during hot embossing of polymers by simulating the process with a new viscoplastic model and optimizing parameters.

## Contribution

The study introduces a two-layer viscoplastic model and optimizes processing parameters to enhance micro-scale hot embossing.

## Key findings

- Viscoplastic parameters were characterized from stress–strain curves of two polymers at different temperatures.
- Optimized processing parameters achieved complete filling of micro cavities in simulations and experiments.
- Friction and temperature significantly influence mold filling behavior at the micro scale.

## Abstract

The filling efficiency during the hot embossing process at micro scale is essential for micro-component replication. The presence of the unfilled area is often due to the inadequate behavior law applied to the embossed materials. This research consists of the identification of viscoplastic law (two-layer viscoplastic model) of polymers and the optimization of processing parameters. Mechanical tests have been performed for two polymers at 20 °C and 30 °C above their glass transition temperature. The viscoplastic parameters are characterized based on stress–strain curves from the compression tests. The influences of imposed displacement, temperature, and friction on mold filling are investigated. The processing parameters are optimized to achieving the complete filling of micro cavities. The replication of a micro-structured cavity has been effectuated using this process and the experimental observations validate the results in the simulation, which confirms the efficiency of the proposed numerical approach.