4M Knowledge base - papers

V. Piotter, G. Finnah, K. Plewa, R. Ruprecht, J. Hausselt
Forschungszentrum Karlsruhe, Institute for Materials Research III, P.O. Box 3640, 76021 Karlsruhe, Germany

Abstract

In recent years Microsystems Technology products made by thermoplastic injection moulding have steadily entered the worldwide market, and this trend will certainly continue in the next years. On the other hand, there is still a lack of methods for the processing of materials other than thermoplastics, and there is also the necessity to reduce assembly expenditures.

To improve the materials variety the so-called Micro Powder Injection Moulding (MicroPIM) process facilitates a medium- and large-scale fabrication technology for metal and ceramic micro components. Examples are micro gear wheels manufactured on a specially equipped micro injection moulding machine. Minimum dimensions achieved so far are 50μm of part thickness or minimum structural details of less than 10μm. Densities up to 99% of the theoretical values were achieved depending on the particular powder applied. Typical materials are oxide ceramics, conductive ceramics, alloyed steels, or hard metals.

A remarkable new approach is the realization of material combinations like conductive/non-conductive or magnetic/non-magnetic within one singular part by two-component MicroPIM. The main technical challenges are the process parameters which have to be suitable for both materials and the question of adhesion in micro areas. As merging and shaping takes place simultaneously, expensive mounting steps can be omitted.

V. Piotter, K. Plewa, J. Prokop, A. Ruh, H.-J. Ritzhaupt-Kleissl, J. Hausselt
Forschungszentrum Karlsruhe, Institute for Materials Research III P.O. Box 3640, 76021 Karlsruhe, Germany

Abstract

Although microsystems technologies products have been steadily launched worldwide markets the development and improvement of manufacturing processes suitable for medium or large-scale production is still one of the most important prerequisites.
A well-known technology to meet such demands is micro injection moulding which has already reached an industrial viable status for polymeric materials. Nevertheless, there is still a lack of methods for the processing of materials with a wider range of properties.
A promising option to close this gap, development of the so-called MicroPIM process to facilitate the fabrication of metal and ceramic micro components was started.
Presently, the smallest dimensions achievable are 25-50μm of part thickness or minimum structural details of less than 5μm. Theoretical densities of up to 99% were achieved depending on the particular powder applied. As further improvement, the technology to produce rotational-symmetric parts by making use of a special head spindle system has been developed.
To enlarge the application possibilities of MicroPIM further, micro two-component injection moulding enables, for example, the fabrication of micro components consisting of two ceramic or metal materials with different physical properties and, not less important, significantly minimises assembly expenditure.

J. Prokop (a),(b), J. Lorenz (a), V. Piotter (a), H.-J. Ritzhaupt-Kleissl (a), A. Roch (a), and J. Haußelt (a),(b)

(a) Forschungszentrum Karlsruhe GmbH, Institute for Materials Research III (IMF III) Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
(b) Department of Microsystems Engineering - IMTEK, University of Freiburg, Germany

Abstract

A process for the fabrication of metal micro components by combining 2-component injection moulding with metal deposition by electroforming will be presented. To produce these 2-component polymer templates, an electrically conductive base plate is generated by injection moulding of electrically conductive carbon black-filled polymers. In a second injection moulding step microstructures consisting of insulating polymers are mounted onto these plates. The quasi-infinite conductivity gradient of such 2-component templates allows controlled electroplating to start from the base plate only, such that defect-free metal micro components can be achieved. The parameter set of the injection moulding process has been investigated by using an experimental method with an x-ray pattern analysis. Nearly defect-free electroplated micro parts could be fabricated by this process so far.