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Advanced Polymeric COmpounds and Metal Matrix Composites for Excellent Performances in Machine Tools applications

Periodic Report Summary - COMETA (Advanced polymeric compounds and metal matrix composites for excellent performances in machine tools applications)

Project context and objectives:

The COMETA project aims at solving the following problems of Small and medium-sized enterprise (SME)s European machine tools manufacturers:

- get high 'thermal' stability, in order to minimise thermally-induced errors arising from thermal deformations of the machine structures caused by internal / external heat sources;
- get high 'dynamic' stability, in order to minimise vibration (forced and chatter) and inertial effects of machine structures.

COMETA intends to reach these goals through the integration and tailoring (to specific need machinery sector) of innovative materials, and exploiting a double-side solution:

- Novel and mouldable polymeric Short fibres 'compound' (SFC) to be used to produce complex parts (flanges, inserts) of machine that are used to interface mechanical components (e.g. motors, guideways, spindle) with the rest of the structure made of composite. The proposed SFC is composed of reinforcement (glass or carbon) with short fibres, powdered or impregnated with proper percentage in volume of thermoset or thermoplastic resin. Switching from metal interfaces (aluminium / steel) to compound material would bring: extremely lower thermal drift, weight reduction, thus lower energy consumption and lower part inertia, no galvanic corrosion.
- Aluminium matrix composite (AMC) materials to design and realise low-weight (and hot) parts of machines with excellence mechanical performance (e.g. spindle case, bearing spacer, multi-spindle head, motor base). The reinforcement in AMCs could be in the form of continuous / discontinuous fibres, whisker or particulates. Properties of AMCs can be tailored to the demands of different Machine tool applications by suitable combinations of matrix, reinforcement and processing route. The major advantages of AMCs compared to unreinforced materials are as follows:

- improved stiffness to weight ratio;
- improved high temperature properties; controlled thermal expansion coefficient;
- improved abrasion and wear resistance;
- improved damping capabilities.

Project results:

The COMETA project started on 1 December 2009. During the first 18 months of the project, COMETA consortium set up a well-defined structure based on a clear share-out of roles. A 'machine tool experts' team, made up by FIDIA, CeSI, Moeck, IMA TECNO and IfW, focused its initial activity on defining and proposing a starting list of application case studies based on real machine tools application of innovative materials. This has been made with the following objectives:

- to drive from the very beginning research activities towards exploitation-oriented objectives;
- to clearly define concrete specifications from the technical, performance and cost points of view.

On the other hand, a 'material task force', constituted by AMRC Ltd, SICOMP, LOLA and TEKS, has been set up with the aim of assessing the list from the feasibility point of view, with the aim of converging to a final list of case studies on which to focus research, development, manufacturing and demonstration efforts.

The objective of achieving a final list of case studies by M6 (May 2010) has been fulfilled. From that point, selection, tailoring and characterisation of materials (WP2) have been carried out successfully, also thanks to the clear definition of application scenarios. This activity led to a definitive selection of materials, enabling the definition of the manufacturing routes. In fact, the strong innovation brought out by COMETA lies mainly in the development of manufacturing processes which allow the realisation of machine tools components which are:

- targeted to the technical needs of machine tools;
- targeted to the small numbers which characterise this sector;
- targeted to SMEs' needs and capabilities.

In parallel, material selection, analysis and has been supported by simulation tools, which has been selected, tailored and applied keeping in mind the relatively low resources available for SMEs trying to take advantage from the use and application of innovative materials.

Potential impact:

COMETA will have a huge impact on the production equipment industry, which is one of the strategic European industrial sectors and is strongly characterised by the presence of SMEs. SMEs make up 99 % of all enterprises in Europe, account for the majority of new jobs created, and make an important contribution to achieving the European Union's goal of more growth and more and better jobs. So the value of SMEs to an economically competitive Europe is therefore enormous.

Each of the material technology addressed by COMETA, which are SFCs and AMC-based materials, responds to specific innovation needs and applications (where problems are diverse) within the area of precision machine tools development in order to provide a global exploitable solution: SFC are mainly targeted to lightweight mobile structures (medium-large size), made of assembled parts which requires high damping, while the AMC is targeted to components (small-medium size) which required very high accuracy, superficial hardness and quite high operation temperature.

The implementation of new, high-added-value materials resulting from the COMETA proposal in the machine tools sector will have a twofold impact in the medium-term innovation in such field. From one side, the implementation of the SFCs will allow the effective exploitation of a number of already developed technical solutions in the short-term, such as the utilisation of light and stiff composite materials for manufacturing different machine parts. As an example, rams made by Carbon fibre reinforced composite (CFRP) have already been developed, but their exploitability encountered several critical problems, which will be solved with the implementation of SFCs. From the other side, the research on high performance materials such as AMCs will outcome in the short/medium term exploitability of a number of results, such as mechanical components design and production methodologies, as well as analysis and development of tailored AMCs specific for the machine tool sector.

List of websites: www.cometaproject.eu