1985 Fiscal Year Final Research Report Summary
Ultra-Precision Vertical Spindle Grinder for Ceramics
| Project/Area Number |
59850028
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
1984 – 1985
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| Keywords | Ultra-Precision Grinder / Fine Ceramics / Thermal Rigidity / Mirror Grinding / Rigidity / Hydro-Static Oil Bearing / 鏡面研削 / 加工変質層 |
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| Research Abstract |
Single crystals and glass ceramics of zero thermal expansion coefficient are expected to be machined ultra-precisely in near future. These materials have been lapped and polished because of their brittle mechanical properties. This research intends to develop a new ultra-precision vertical spindle grinder which can finish ceramic materials into flat mirror surfaces having sub-micron in dimensional accuracy. It is the most important to control the thermal expansion of materials to be ground, a grinding wheel and machine tool for getting the sub-micron accuracy in grinding process. This research tried to reduce such thermal expansion by two methods, that is, using of glass ceramics of zerothermal expansion coefficient as a material of a grinding wheel spindle and controlling the temperatures in room, grinding water and hydrostatic pressure oil for making the temperatures of a machine tool, grinding wheel and workpiece uniform. No body has developed a glass ceramic spindle because of brittleness and expensive cost for machining. By development of new casting ＆ heat treating processes and examination of grindability and polishability of the glass ceramics, the first grinding spindle made of glass ceramics having zero thermal expansion coefficient has been designed and manufactured. Depth of cut in grinding process is numerically controlled in the unit of 0.1 micron/pulse which is performed by the rigid spindles and bearings for a grinding wheel and table. Hydrostatic oil bearings are designed and manufactured having the features such as low thermal expansion, higher rigidity and higher revolutional accuracy. MnZn ferrite single crystal surfaces of 0.08micron in flatness and of 0.015 micron Rz in surface roughness were obtained by using this new grinder. By development of dressing and a grinding wheel, the smoother surface of less than 0.01 micron Rmax will be obtained by the machine.
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