Investment Casting of Microparts made of Co-Cr-Mo Alloy
A. Silva1, L. Ribeiro1, F.Viana1
1 CEMUC, Dept. of Metallurgical and Materials Eng., Faculty of Engineering, University of Porto, Portugal.
The developments in micro and nanomanufacturing technologies are a global trend due to the increasing demand for parts miniaturized with technical applications in several areas, such as, biomedical, pharmaceutical, microelectronics and mechanical engineering.
Microcasting is a metal forming process based on the lost-wax technology of investment casting which is capable of produce small structures in the micrometer range, or larger parts carrying microstructural features. This process uses a molten metal which is cast into a ceramic microstructured mold .
The production of microcomponents by investment casting requires a special control of the variables at each stage of the process, such as, melting and mold temperature, filling pressure and pattern and investment materials.
The purpose of this work is to perform a detailed analysis of the investment casting process, to select and to establish the most important variables for production of microparts made of Co-Cr-Mo alloy. To fulfill this objective, it is essential to characterize the influence of the process parameters on the structure, surface finish and properties of the microcomponents.
Some microparts, including specimens for tensile tests with a total length of 15 mm and a rectangular cross-section of 0,5×0,5 mm2, were fabricated using photopolymer patterns, phosphate bonded investments and centrifugal casting. The dimensional accuracy, surface roughness and microstructure characterization were performed on the microparts fabricated.
 H. Baltes, O. B., G. K. Fedder, C. Hierold, J. Korvink, O. Tabata (2005), Microengineering of Metals and Ceramics -Advanced Micro & Nano systems, Wiley-vch, Weinheim, 357- 393.