Application of multifunctional materials for machine tool structures

The competition on the international markets pushes manufacturers towards shorter design cycles and decreasing manufacturing times and costs for their products. This trend generates a demand for smart, flexible and faster machining systems, easy to set up and configure, which are able to drastically reduce machining time and improve the final accuracy. This paper rises from these considerations evaluating the possible application of multifunction materials in machine tool (MT) design and building. These solutions can provide a fundamental impact on functionality and reliability of a manufacturing system. In particular, use of innovative materials in today's technology continues to grow steadily. Numerous reasons for this growth include light weight, superior insulating abilities, energy absorbing performance, excellent strength/weight ratio and low cost. This paper aims to investigate a possible application of multifunction materials in realisation of structure components for Machine Tools. There are many aspects that affect the machining accuracy and the cutting conditions of a high performance MT. The most important issues are related to the static, dynamic, mechatronic and thermal behavior of the machines. In particular, a strict requirement that a machine tool has to fulfill in order to drastically reduce operating time while improving the final accuracy is the thermal stability. This paper shows a complete study and testing validation on prototypes (plates and beam) based on sandwiches with core made of metal foam (open and closed cells) materials impregnated by a PCM (Phase Material Change) wax. Metal foams represent a class of materials with low density and novel physical, mechanical, thermal, electrical and acoustic proprieties. They offer potential for lightweight structures, for energy absorption and thermal management. PCMs are latent heat storage materials that absorb heat keeping constant the temperature of a machine component in a defined time range. The authors have designed, realized and tested the prototypes developing thermal trials, and then evaluating the comparison between experimental data and simulative analysis (FEM). The trials consisted to process the prototypes at a variation of temperature in order to assess the PCM proprieties to absorb heat and maintain thermal stability in a defined time range. The paper shows also a simulative study on PCM material behavior and their application in MT design supported by experimental trials and data analysis. The significant advantages and perspectives that can be obtained in applying of these MT structures complete the developed study.