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Mechanical Engineering Laboratory 1990 March |
| 20-1 High Quality Grinding of Difficult -to- machine Materials | 
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High Quality Grinding of Difficult -to- machine Materials This project comprises an investigation of advanced grinding techniques (ultrasonic grinding, electrochemical grinding, and new structures of grinding wheels) for the high precision and damage free machining of. difficult -to- machine materials. The application of ultrasonic vibration have led to a reduction in grinding force of about 75% together with a high quality finish with no edge-cracking, in the production of through holes in ceramic components. Wheels with new structures have also been developed for creep feed grinding, having slots and perforations on the wheel periphery for the efficient supply of grinding coolant. An electroplated CBN wheel incorporating these features has been shown to be highly efficient in grinding nickel-base alloys, with depths of cut up to 10mm. |
| 20-2 Novel Machining Techniques for New Materials | 
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Novel Machining Techniques for New Materials Novel machining techniques are required for the new generation of materials currently under development, and to meet the increasing quality requirements of modern industry. For instance, super-smooth surface finishes are often required for adhesion prevention and corrosion resistance. This project, includes investigations of techniques such as: Electro-abrasive mirror finishing (a surface roughness of less than 0.05 micron Rmax can be obtained with this method), mechano-chemical polishing, and machining using an electrical discharge in an electrolyte. In this last technique, material is removed from the work-piece (a non-conducting ceramic) by the heat and chemical action associated with the discharge, the process being controlled by an infrared detector viewing the process. |
| 21-1 Advanced Technology for High Precision Machine Tools | 
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Advanced Technology for High Precision Machine Tools Ultra-precision Machining Machining to manometer order accuracy requires advanced machine tools incorporating special techniques, and a detailed understanding of micro-machining processes. This project aims to establish the fundamental teclmology required to achieve this type of high order machining capability by research as follows : Development of optical in-process measuring methods for determining spindle rotational accuracy, together with development of spindle autobalancing techniques. Application of new materials to slide ways, and develop ment of techniques to control thermal deformation. Investigation of the micromachining mechanisms involved in diamond turning, and the development of ultra high precision machining techniques for brittle materials. |
| 21-2 Ultra-precision Machining | 
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Ultra-precision Machining The aim of this project is to establish the manufacturing technology required for the production of large aspherical metal mirrors. Subjects under investigation include : Diamond turning, surface form measurement and improvement of surface accuracy by measurement and compensation systems. Research is also under way towards improving the performance of this type of precision machine, by integration of mathematical modelling of the machine structure with the results of vibration tests. |
| 22-1 Micromachining of Hard Tissue | 
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Micromachining of Hard Tissue During surgical operations it is often necessary to cut or grind hard tissue, such as bone. This is currently achieved using conventional techniques, and the success of the machining operation is, as a result, very dependent on the surgeon's experience. Laser or water-jet techniques have the possibility of improving on conventional methods, particularly where micro-machining is required. This project consists of basic research towards the practical application of these new techniques, and includes investigations into the accuracies achievable, and the degree of damage tolerance which might be expected. |
| 22-2 Advanced Joining Techniques | 
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Advanced Joining Techniques New materials such as ceramics and amorphous alloys are currently the subject of much attention. Since these materials are usually expensive and difficult to form, there is a requirement for techniques to bond them to conventional metals or alloys in industrial applications. There are several problems associated with bonding these materials using conventional welding or brazing methods, such as crack formation, structural changes occurring at high temperature, and so on. This project centers around the development of new joining processes for these unusual materials, and includes investigations of: Solid state bonding under ultra-high vacuum, Friction welding using an intermediate layer, and Impulsive current brazing. Magnetically controlled TIC−MIG complex arc welding is also under development, with the aim of improving process efficiency and weld reliability. |
| 23-1 Automatic Determination of Tool Wear | 
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Automatic Determination of Tool Wear A measurement system for the determination of tool wear is being developed in order to generate machinability data for various kinds of new materials. The most important tasks are the determination of the flank and crater wear of the cutting tool. A measurement system for the flank wear has already been developed which uses computer-aided image processing, and current research is aimed at the development of an automatic focus system for determination of the three-dimensional shape of the crater wear. The photo shows the crater wear measurement system, where the crater wear is determined by analyzing variations in the position of the image of a focused point of light, using a TV camera and computer. |
| 23-2 Intelligent Machining System | 
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Intelligent Machining System The aim of this project is to integrate intelligent sensing systems and on-line knowledge-based systems into CNC machine tools. An autonomous machining cell is being developed which makes extensive use of artificial intelligence techniques. In this cell, an expert knowledge-based system determines the optimum machining conditions, and an event-driven knowledge-based system controls the machining process. The success of the autonomous control process depends very much on the availability of intelligent sensing systems. |
