Process planning considerations for micromilling of mould cavities used in ultrasonic moulding technology

The current trend in miniaturization of products and components requires appropriate technologies for the manufacture of miniature dies and moulds. The work presented here deals with the process planning of micromilling for the production of miniature mould cavities, required in ultrasonic moulding in order to reach high precision. Several aspects of process planning are addressed, including cutting tool geometry selection, segmentation of cavity geometry, minimum chip thickness, chordal tolerance, and type of interpolation. The case study involves the successful micromilling of a complex aluminium mould cavity for ultrasonic moulding. The proposed process plan is demonstrated through the micromilling of the mould cavity and silicone replicas of the miniature geometrical model. In general terms, good precision is obtained following the proposed methodology. In a randomly located set of geometric features, the dimensional error was below 5% for most features (32 out of a total of 40)The authors would like to express their gratitude to the Product, Process and Production Engineering Research Group from University of Girona for the facilities provided during the experiments and all their valuable support. Tecnologico de Monterrey also provided support through its research group in Intelligent Machines. Also, this work was carried out with the collaboration of Ascamm Foundation through their spin-off ULTRASION S.L. This work was partially supported by European Commission project IREBID (FP7-PEOPLE-2009-IRSES-247476) and the Science and Innovation Minister project TECNIPLAD (DPI2009-09852