4M Knowledge base - papers
Multi-Component Micro Injection Moulding – Trends and Developments
V. Piotter(a), G. Finnah(b), J. Prokop(a), R. Ruprecht(a), J. Hausselt(a)
a: Forschungszentrum Karlsruhe, Institute for Materials Research III, P.O. Box 3640, 76021 Karlsruhe, Germany
b: Robert Bosch GmbH, Waiblingen, Germany
Abstract
With standard micro injection molding becoming more and more established in practical manufacturing, special variants are attracting increasing attention. Especially the approaches on multi-component micro injection moulding have to be mentioned: As handling and assembly are difficult procedures especially in micro technology, methods to reduce mounting efforts are of high economic importance. By merging of shaping and mounting procedures in one step economic progress as well as new material combinations can be obtained. An interesting approach for the fabrication of metal (or, in principal, ceramic) micro components is the combination of insert injection molding and metal deposition by electroforming. First, an electrically conductive base plate is produced by injection moulding of conductively filled polymers. In a second injection moulding step microstructures consisting of insulating plastics are mounted on these plates. The quasi-infinite conductivity gradient allows controlled electroplating starting at the base plate only, so that defect-free metal micro components can be achieved. As a further variant of micro injection moulding, the development of the so-called MicroPIM process facilitates a large-scale series fabrication technology for metal and ceramic micro components. Combined with multi-component technology, an interesting new approach for micro manufacturing is obtained, i.e. the realization of magnetic/nonmagnetic or conductive/non-conductive material combinations by two-component MicroPIM.
categories
ElectroplatingSimulating electroplated micro surfaces in 3-D
A H. J. Jeon (1), J Low (1), A. R. Mileham (1), A.N. Bramley (1), C. Johal (2)
1 Department of Mechanical Engineering, University of Bath, BA27AY, UK
2 Glacier Vandervell Bearings Ltd, Rugby, UK
Abstract
This paper describes the development, comparison and validation of a 3-D model of the electroplating process. It is based on the current density distribution that is generated using the Finite Element Method (FEM) and is used together with Faraday's law of electrolysis and various material and electrolyte values to determine the local plating depth. It has been developed initially to model the depth of the micro layer deposited on the work surface of an automotive engine’s "big end" shell bearing. Actual plating trials were conducted in a series of controlled laboratory experiments using an industrial type jig and industrial plating conditions. These consisted of a steel cathode (the bearing) and a lead anode. The results described here, in this paper, show good agreement between the 3-D simulation and the actual plating depth and profile and are considered to validate the model sufficiently for it to be used for electroplating tooling design and micro-electroforming.
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