Simulation and Experimental Validation of the Hot Embossing Process of Poly(lactic-co-glycolic acid) Microstructures

The microstructures were fabricated by hot embossing method using biodegradable material PLGA poly(lactic-co-glycolic acid), to serve as the drug carriers in the drug delivery system. The embossing process was studied in a combination of simulations and experiments. Firstly, the viscoelastic model of PLGA was built after testing the material properties. Secondly, the hot embossing process was simulated by ABAQUS finite element software. The deformation rules of PLGA during hot embossing were then achieved. The pressures inside the PLGA materials were different at various places during hot embossing, which lead to the differences of the filling speeds. As a result, the inner structures were easier to get formed than the outer structures. And the fluidity of PGLA would increase with the raising temperature, which however caused serious material overflow. Finally the hot embossing experiments were presented to verify the simulation results. Agreed with the filling rules of the simulation, enough duration was necessary to let the outer corners of the microstructures be formed completely. Moreover the trapped air in the grooves was compressed into small bubbles at the corners. It was also found that the material overflow could be prevented in the use of nonisothermal hot embossing method