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Title Filling of micro injection moulded parts: an experimental investigation
Author Guarise, Matteo
Supervisor Hansen, Hans Nørgaard (Institut for Produktion og Ledelse, Danmarks Tekniske Universitet, DTU, DK-2800 Kgs. Lyngby, Denmark)
Tosello, Guido (Institut for Produktion og Ledelse, Danmarks Tekniske Universitet, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2007
Abstract In the last years the employment of micro component has been constantly increasing. Conventional technologies are no longer suitable for mass fabrication of micro scaled products. Therefore technologies are being developed in order to produce such small components. Micro injection moulding is one of the key technologies for mass fabrication of micro components. It matches the capabilities of a low cost process, as injection moulding, and the requirements of micro products, as small dimensions and low tolerances. In conventional injection moulding, the “short shot” tecnique is used in order to understand how the filling of the cavity occurs and how the process parameters affect it. This tecnique is of very difficult application in micro injection moulding. Hereby a new approach to understand the filling of a micro cavity is presented. In this thesis work the filling of a micro cavity has been analysed using the weld lines as flow markers. The influence of melt and mould temperature, injection speed and packing pressure on weld lines position and shape has been investigated. The weld lines of workpieces obtained from a factorial plan designed trials (24=16 trials) have been characterized by a two dimensional investigation. For this purpose, an optical CMM has been used. The uncertainty affecting the measurements has been also evaluated. Once all the measurements have been completed, two analyses have been carried out: a one parameter at time analysis and a statistical analysis. Both of them have highlighted that the injection velocity and mould temperature have the highest influence on the filling of micro cavities. Also the geometry and dimensions of micro channel affect the filling. Finally, the influence of the measuring uncertainty on the reliability of the statistical analysis has been investigated. It has been determined that the influence of a term on the response can be evaluated just whether the uncertainty is lower than the 30% of the term effect.
Pages 177
Original PDF M_Sc_thesis_Matteo_Guarise.pdf (5.08 MB)
Admin Creation date: 2008-02-08    Update date: 2008-02-08    Source: dtu    ID: 210410    Original MXD