MACHINING OF MICRO MOULDING INSERTS

Abstract

As the demand for miniaturised products is on rise in biomedical, defence, microfluidics, and electronics, low cost manufacturing processes for these micro products is need of the hour. Precision replication processes like micro injection moulding & micro hot embossing are the viable solution for low cost production of polymeric micro products. These processes require micro moulds which are most critical in determining the quality of the final products as the geometry of the mould is transferred to the final product with some errors of the processing window. The manufacturing of these moulds is carried out using different routes like lithography, etching, electroforming etc. and non lithography route which use Laser micromachining, micro EDM, micro ECM, and mechanical micromachining particularly. This research work is an investigation on the machining of micromoulding inserts on titanium. It will help in incrementing the knowledge database which will be useful in selecting the machining parameters and conditions for maximizing surface quality with acceptable MRR on titanium material. The work aims at realisation of micromoulding insert on titanium. This investigation is an integrated effort which included the study of milling strategies in addition to the critical cutting parameters like feed, speed, axial and radial depth of cuts by machining microchannels and micropockets. The issues related to process planning and tool-workpiece settings were also investigated by machining a test micro cavity on aluminium alloy in which tools of size 200μm and 100μm were used. Taguchi experimental design and ANOVA statistical techniques have been used to understand the influence of machining parameters and tool paths on the process response (surface finish and burr formation). In addition to it surface topography of the machined surfaces were also investigated qualitatively. The acquired knowledge was used in the machining of complex micro geometry on titanium grade-2 to be used as micro moulding insert.