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Modelling of cold compaction

Objective



Powder metallurgy (P/M) is the major manufacturing route for a wide range of industrial parts such as transmission and gearbox steel parts for automotive, cem ented carbides and high speed steels for metal-, wood- or stone-working, magnet s and soft magnetic materials, fine ceramics, refractory metals, bearings... A ll these parts are produced by cold pressing a powder in a die and sintering th e resulting green body in a furnace. Although the problems are different in d etails, all these branches encounter the same practical difficulties: - in most cases, a post-sintering operation (sizing or machining) is necessary to obtain the final geometry of the parts. This operation represents 10% to 25% of the p roduction costs. - a tool set for die pressing costs between 1.000 and 100.000 ECU. The design of a tool set for a new product is made with a trial-and-error procedure that generates overcosts (up to 50% of the initial tooling costs) and delays (several weeks or months). - about 2% (and far more for new fabrication s) of the parts are defective due to the presence of cracks. The need of a fina l control and the value of the rejected parts strongly increase the global prod uction costs. Savings for European industry estimated between 100 and 150 MECU appear to be possible on development and production costs and time-to-market co uld be markedly improved: - if the as-sintered parts could be more accurate, - if the tool design could be based on reliable predictive methods, - if the proc ess could be well designed, so that no cracks occur. This could be obtained by replacing the common trial-and-error procedure by a more efficient approach usi ng predictive methods based on numerical simulation. Consequently, the objectiv e of the MC2 Project is to develop the industrial modelling of the whole P/M pr ocess for the wide range of materials concerned by this technique. It is expect ed that crack-free parts with high geometrical accuracy (10 pm or 0.1%) and den sity homogeneity can routinely be produced, if the design of the parts, of the pressing tools and of the pressing schedule is based on a numerical simulation that integrates the knowledge generated experimentally and theoretically in thi s project. To achieve this goal, the technical programme will include - the se lection and implementation of existing macromechanical models for cold compacti on, friction and sintering in suitable finite element codes - the experimental determination of materials data for several reference materials - the validat ion and optimization of the numerical modelling, the simulation and the fabrica tion of reference parts - the comparison between computed and experimental res ults in term of geometry, density distribution, residual stresses and mechanica l strength. The project will end with the specification and the design of an i ndustrial modelling tool usable in all powder industries. The MC2 project is pr esented with the full support of the European Powder Metallurgy Association (EP MA) which represents 80 companies or manufacturing groups i.e. 80% of the Europ ean Powder Metals Industry (see letter in Appendix). The proposed project will comply with the aims and objectives of Brite Euram III programme in the general technical areas 2.1.1 .M (New more accurate and energy efficient near net shap e powder metallurgy to reduce costs, energy and waste in the mass production of components), 2.2.1.S, 2.2.2.S.The MC2 project is proposed in the scope of PM- MODNET , a Thematic Network funded by the EC in the frame of the IMT Programme (n› BETN-0010). The objective of this Network coordinated by the EPMA is to exa mine the possibility to initiate projects on the modelling of P/M processes.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Commissariat à l'Energie Atomique
Address
Rue Des Martyrs 17
38054 Grenoble
France

Participants (8)

Aimants Ugimag SA
France
Address
Route D'uriage
38830 Saint-pierre-d'allevard
Aleaciones de Metales Sinterizados SA
Spain
Address
388,C/ Laurea Miró 388
8980 San Feliu De Llobregat
Cerametal SARL
Luxembourg
Address
Route De Holzem 101
8201 Mamer
FEDERAL-MOGUL Technology Ltd.
United Kingdom
Address
Cawston Lane
CV22 7SA Rugby
FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG E.V.*
Germany
Address
Woehlerstrasse 11
79108 Freiburg (In Breisgau)
Höganäs AB
Sweden
Address

263 83 Högands
INSTITUT NATIONAL POLYTECHNIQUE DE GRENOBLE
France
Address
Domaine Universitaire, 1023 Rue De La Piscine
38041 Grenoble
LULEAA UNIVERSITY OF TECHNOLOGY
Sweden
Address

971 87 Lulea