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Injection molding of hollow components

Objective


According to the project programme, the major deliverables have been achieved as planned. No significant deviations between planned and actual work have been encountered. Task 1 and 2 (in particular the sub-task 1.1, 1.3, 2.1 and 2.2) have been completed as planned; sub-task 1.2 has been extended to the month 21 to allow a more robust design of project final demonstrators, requiring reliable materials properties. Task 3, 4 and 5 are still in progress as planned. Main partners involved in Task 3 (ENSCI, POLI TO, CERECO and IFAM) have investigated the perfect combination between powders, binders and low fusible alloys to apply the lost core technique to PIM parts. In particular, the technical work focused on i) the definition of an organic binder system suitable both for metallic and ceramic powders and ii) the definition of the right low fusible alloy in order to perform injection molding, debinding and sintering without distorting, polluting or damaging the components.

In particular, the development of reliable powder injection molding technologies for hollow components has been carried out by the integration of the different competencies, from materials sciences to mechanical engineering through process simulation and modelling. The research efforts have been devoted to the proper selection of materials and related processes and to the development & optimisation of the overall process through modelling and representative mock-ups manufacturing.

Concerning the materials analysis and selection (Task 3), CRF, POLI TO, CERECO and ENSCI co-operated with the purpose to tune all processing steps regarding silicon nitride, MMCs and CMCs materials. Debinding and sintering tests of different silicon nitride and sintering aids compositions have been carried out, leading to good results in terms of final density and material microstructure of sintered parts.

Process development and optimisation (Task 4) was focused on the production of two representative mock-ups (small hollow components and tensile and flexural specimens) as intermediate testing of the project achievements. All steps were performed, but some technical problems concerning the metallic cores rose up prevented the achievement of crack-free mock-ups. Cracked parts were however debinded and sintered (with and without the RCP technique) without major problems. As a result, representative mock-ups were not accomplished since pore-free cores has not been manufactured yet, but, once they will be available, the mock-ups will be manufactured. All processing conditions were delivered as planned, except the production of fusible cores and, consequently, the representative mock-ups, will be delivered by month 21.

After the mid term assessment, partners will concentrate on the solution of technical challenges identified and then on the manufacturing and testing of real industrial parts for the final assessment of the project results.
Objectives and content: Currently, in many industrial sectors injection moulding is widely applied for manufacturing of plastic components. Besides, it's also well known a variety of technologies enabling the production of hollow structural parts. We believe profitable to develop an original processing system to manufacture hollow parts with ceramic or metal materials, based on ceramic and metal injection moulding technologies (CIM and MIM respectively). Therefore the aim of the proposed project is the development of complex shaped, hollow components by injection moulding of ceramic and metallic powders. Manufacturing by injection moulding makes possible the achievement of very complex, net shape parts without successive machining, resulting in cheaper forming operations and lower total costs. Moreover, this kind of process allows tailoring materials' properties to designer's needs, improving the performances of the product. Generally speaking, usage of hollow parts, like a camshaft in an automotive engine for example, reduce the weight of rotating masses and, as a consequence, optimise the vehicle energy efficiency. Evidently, there are a lot of small elements, specially in the engine compartment, which would deserve complex constructions, closed box sections, avoiding as much as possible machining operations.

These considerations drive us to the development of specific forming technologies, which are not yet, matter of present industrial knowledge:
- identification of methods to reduce the oxygen content into the sintering furnaces, eliminating or decreasing the use of expensive reducing atmosphere;
- identification of special low fusible alloys to guarantee a perfect melting out of the lost cores from the expected hollow components (lost core technique);
- identification of calculation system of through predicting of all shrinkage and other movements which may occur during sintering operations.

In particular, in the present project, dealing with metallic and ceramic components, the main objective is the development of two final demonstrators: a stainless steel tap for metals and a cam shaft for ceramics. In our opinion, the advantages of an injection-moulded tap could be near net shape manufacturing, tailored material properties and an optimised surface aspect. Also we will substitute conventional, polluting alloys like brass (containing lead) with a safer material like stainless steel. Furthermore we can consider that in the automotive field, a ceramic part like a camshaft will improve the global efficiency of the engine, getting significant advantages in part weight, wear and thermal properties (less fuel consumption - pollution).

The project will be organised in the following main tasks: component selection and specifications; process simulation; materials selection; process development & optimisation; moulds design & manufacturing; parts manufacturing; final components evaluation; dissemination of final results. BE97-4980

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CENTRO RICERCHE FIAT S.C.P.A.
Address
Strada Torino 50
10043 Orbassano
Italy

Participants (9)

CERAMICS AND REFRACTORIES TECHNOLOGICAL DEVELOPMENT COMPANY S.A.
Greece
Address
5Th Km,athens-lamia Road 72 Km
34100 Chalkida
Dimp S.A.
Spain
Address
13,Llgaldetxo
20180 Oiartzun
FUNDACION GAIKER
Spain
Address
Parque Tecnologico De Zamudio, Edificio 202
Zamudio
Fraunhofer-Gesellschaft zur Förderungder Angewandten Forschung e.V.
Germany
Address
Lesumer Heerstraùe
28717 Bremen
Hamat Sanitary fittings and Castings Ltd.
Israel
Address
41,Hayozma Street
77100 Ashdod
MATERIALS RESEARCH CENTRE
Italy
Address
Via Di Castel Romano 100/102
00128 Roma
POLITECNICO DI TORINO
Italy
Address
Corso Duca Degli Abruzzi 24
10129 Torino (Turin)
Reef Tecnica Srl
Italy
Address
41,Via Delle Industrie
28048 Verbania
École Nationale Supérieure de Céramiques Industrielles de Limoges
France
Address
47-73 Avenue Albert Thomas
87065 Limoges