Session: FSI-04-01 FSI Design for Industry and Renewable Energy Transport - 1

Paper Number: 105915

105915 - Feasibility and Optimization of Nozzle Flapper System for Position Measurements of High-Speed Rotation Spindle With Aerostatic Bearings 

In recent years, due to the growing demand for semiconductors, there is a need of increasing the rotating speed and improving machining accuracy of the semiconductor-processing spindles to achieve a higher processing efficiency. Spindles, loaded with aerostatic air bearings, were proposed as a feasible solution to achieve higher rotating speed, but as for the higher machining accuracy of the semiconductor, still lacked an effective position measurement method as the part of a compensation strategy for the shaft's offset (30μm of the maximum radial offset of the shaft)  due to the processing resistance load  (4.5 kgf of the maximum radial processing resistance load) and high rotating speed of the shaft.

In this report, position measurements for the high rotation speed shaft of the spindle by using the nozzle flapper system were proposed, under the consideration of the same pneumatic characteristics of the aerostatic air bearings, the micron meter-level offset when the spindles are under the processing resistance load, and the small overall size of the spindle. The most important point about the nozzle flapper is that, since the control pressure will be affected by the distance from the nozzle to the flapper, the shape and size of the nozzle, and the size of the orifice, the above multi-fluid structures interact together, therefore, there is currently no theory for the characterization of the control pressure. In this way, the feasibility of proposition could be only and was verified through experiments under the 20,000-rpm rotation speed of the cylinder shaft with the diameter of 16 mm. Meanwhile, it is difficult to secure static characteristic (which required with 30μm distance change of the shaft, the control pressure, as the feedback signal, is able to perform a change of 400 kPa) and dynamic characteristic (which required the frequency respond of the nozzle flapper system reacting around 20 Hz) of the whole control system, because the distance between the shaft and the outer cylinder of the spindle is small. In this case, this report also proposed a kind of multi-hole nozzle flapper systems, introduced the design ideas of them, and conducted the static characteristic and dynamic characteristic experimental tests of them under the shaft rotating speed setting of 20,000 rpm. Later the characteristics comparison between the multi-hole nozzle flapper systems and the single-hole nozzle flapper system were also conducted. The interactional influence of supply pressure, orifice diameter, holes number and diameter of the nozzles on the static and dynamic characteristics are experimentally and theoretically studied and discussed. Finally, the design and adjustment method of the nozzle flapper system are proposed, on the purpose of applying it as a position measurement under the different static characteristic and dynamic characteristic requirements from the control system for the compensation of high-speed rotation spindle with aerostatic air bearings.

Presenting Author: Peimin Xu Tokyo Institute of Technology

Presenting Author Biography: Peimin XU, a sutdent, first year of the Ph.D. from Tokyo Insititute of Technology (2022,10 - ).
The lead author of Multi-hole Nozzle for Position Measurements of High-speed Rotation Air Spindle of The Japan Fluid Power System Society (2022, 11), and Design and Performance Evaluation of an Air Purifier with Porous Filters of Japan Society for Design Engineering (2022,10).

Authors:

Peimin Xu Tokyo Institute of Technology
Kazuaki Inaba Tokyo Institute of Technology
Hisami Takeishi Tokyo Institute of Technology
Toshiharu Kagawa Tokyo Institute of Technology