Manufacturing Technology
　　Manufacturing technology is essential for mechanical engineering. Pioneering and fundamental technologies necessary for the creation of new industries and for existing industries are being developed. This R&D is being carried out domestically while keeping close relations with academic and industrial partners. Internationally, the department is responsible for technology transfer to developing countries and joint research projects with advanced countries, and is playing an important role in the development of environmentally conscious manufacturing technologies.
　
New truing and dressing system for a super-abrasive Surface honing disk
　　In order to maintain high precision in surface honing operations, it is essential that the surface of the honing disk be kept flat and sharp. Truing and dressing super-abrasive honing disks is particularly difficult and this gives great problems in the practical application of this type of disk. A new truing and dressing system for super-abrasive honing disks has been developed (Fig.1). The system consists of a metal-bonded honing disk, an abrasive conditioning ring, a disk-flatness inspection device (not shown) and an electrochemical dressing device. The technique maintains both flatness and sharpness during the honing operation. The flatness of the honing disk is maintained mechanically by the conditioning ring, and the disk surface is dressed electrochemically by removing bonding metal. Experimental results show that the system is capable of maintaining the flatness of a 300mm diameter super-abrasive honing disk to better than 10μm.
　
Fig.1 Truing system for surface-honing disk.
　　
Development of high performance Magnesium alloys
　　Magnesium (Mg) alloys are attractive materials for automotive and aerospace applications because of their low density. However, applications so far have been limited by their relatively low strength and poor corrosion resistance. Improvement of mechanical and corrosion properties is essential to increase the range of applications of these materials.
　
　　 Mechanical properties such as hardness, ultimate tensile strength (UTS), proof stress, and Young's modulus may be improved by reinforcing Mg alloys. Mg composites reinforced with SiC particles (SiCp) were produced by powder metallurgy methods and their mechanical properties were examined.
　
　　The starting materials for the study were AZ91 (Mg-0.9mass%A1-0.8mass%Zn) (38μm powder) and SiCp (0.47μm powder). SiCp was mixed with the metal powder in a ball mill using a mechanical mixer, and the mixture was then hot pressed and extruded.
　
　　Tensile tests carried out at room temperature showed that SiCp reinforced metal alloys have excellent mechanical properties. Results given in the Fig.2 show that UTS and 0.2% proof stress increase with SiCp content up to 15vol%, but UTS decreases when SiCp content reaches 20vol%. Young's modulus increases linearly with SiCp content, and Vickers hardness is also increased. The preparation process is currently being optimised to further improve mechanical properties.
　
Fig.2 UTS and Proot Stress versus SiCp composition
　
　
Smart materials integration for Micro Electro Mechanical Systems
　　Micro Electro Mechanical Systems (MEMS) will be an important new industrial field and are currently under investigation at MEL with particular emphasis on smart materials integration. PZT (PbZr0.52Ti0.48) thin films are of importance for applications such as micro pumps and PZT-driven micro scanners. These devices will be basic components in future micro (and nano) systems for liquid handling and optical processing.
　
Fig.3 Fabricated Scanner with PZT layers (left) and vertical and horizontal scanning patterns
　
Fig.4 FEM simulation of the micro scanner
　
Fig.5 Cross sectional SEM image of Multilayered Structure of the Actuator (μm)
　
　　Materials are the key to smart MEMS. The electrostatic actuators used in conventional MEMS have large energy dissipation, poor control characteristics, and require high accuracy machining for their manufacture. Piezoelectric materials are attractive in this application and, in addition, the use of smart materials has great potential for further miniaturisation because materials such as piezoelectric thin films have several different properties and multi-functional devices can be made with one unit.
　
　　Thick films also have applications in MEMS. Piezoelectric PZT films with thicknesses in the range 1 - 100μm are of great interest for MEMS applications, but it is very difficult to deposit them using conventional techniques. Our work on film preparation includes development of gas phase (pulsed excimer laser ablation deposition), liquid phase (sol-gel method) and solid phase (jet moulding system) techniques.
　
Sliding characteristics of ceramics
　　An experimental investigation into the sliding characteristics of ceramics operating at high speed in plane-plane contact conditions has been carried out. Ceramics such as Alumina-Ceramics or Silicon Carbide have potential for application as lubricant-free sliding surfaces in machine tools. We investigated their characteristics experimentally under conditions almost equivalent to those which would be found in the slide of a machine tool. Fig.6 shows how the coefficient of friction varies with contact pressure and Fig.7 shows how it changes with sliding velocity. When Alumina-Ceramics are used on both faces of the slide, the coefficient of friction increases with both contact pressure and sliding speed - very similar to the characteristics found in metal-to-metal contact. Alumina Ceramics therefore have few advantages over metals in this application. On the other hand, when Silicon Carbide was used in the slide faces it was found that the coefficient of friction can be as low as 0.2. It is also stable against variations in contact pressure and sliding velocity and so has potential application on slide surfaces. However, Fig.7 also shows that a combination of Alumina-Ceramics and Silicon Carbide has a coefficient of friction which is more stable than when Alumina-Ceramics alone are used. The work shows how frictional characteristics may be improved by using an appropriate combination of different materials.
　
Fig.6 Relationship between Pressure and Coefficient of friction
　
Fig.7 Relationship between Sliding velocity and Coefficient of friction
　
Tele-manufacturing
　　The Internet and other similar networks may be used to provide low cost, high quality, remote operation and maintenance of machine tools, thus, helping to overcome space and time constraints. A prototype machine tool which may be monitored and controlled remotely over the Internet has been developed with the aim of establishing the basic technology necessary for development of manufacturing systems suited for use with the Internet.
　　The prototype system consists of a small three-axis milling machine equipped with PC-based numerical control, and a CCD camera and microphone for monitoring the area around the machining position. The system is provided with both client and server functions for the Internet. An important feature of the system is that it uses distributed monitoring architecture which provides a dynamic remote user interface and allows modifications to be made at the client site using only a small number of parameters.
　
　
Fig.8 System architecture of Internet-based machine tools
　
　　Another feature proposed is a Virtual Reality (VR) model driven monitoring system which has potential to provide a man-machine interface with excellent real-time characteristics without the use of multimedia information. The system consists of three elements: a VR model capable of 3D graphical representation of the state of the actual machining system, a number of parameters representing the state of the actual machining system to drive the model, and an engine for driving the model by 3D animation using parameters received from the machine site. The time required for transfer of new parameters depends on the state of the network, but until new parameters are transferred the VR model generates a "current" operating state based on the parameters last received. This method overcomes the practical limitations of the standard Web for remote monitoring of machining processes.

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produced by General Research Counselor