A new pneumatic non-contact handling method is discussed in this paper, in which swirling flow is employed. Air flows into a vortex cup tangentially through a nozzle, and swirls along the wall to make a vacuum at the central area. Then, air is discharged to the atmosphere through a thin gap between the cup and a wafer under the cup. Analysis is conducted by dividing air flow into three parts. They are flow rate characteristics of the nozzle, swirling flow inside the cup and flow through the gap. Pressure distributions inside the cup and the gap are discussed and their analytical results are validated experimentally. It is clear that the vacuum is caused by the swirling air inside the cup, and it depends on the gap and the supply pressure. Furthermore, it is found that the wafer can be handled and kept in a balanced state automatically during a certain range of a considerably thin gap depending on the weight of the wafer. However, the wafer will fall down over this range.

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In this study, a newly designed multi-step pole type actuator was constructed and tested. The cross sectional area of the magnetic path of the newly designed actuator was much larger than that of the formerly reported first prototype. The actuator length was minimized by using a newly designed shape of the teeth. The interval between the teeth was much smaller than that of the first prototype. The thrust characteristics of the newly designed actuator were measured. As a result, the range of armature stroke, where the thrust was constant, was about 2mm. This was approximately two times more than that of the first prototype. Also, it became clear that the length of this actuator was shorter than that of a comparable solenoid on the market whose thrust and installation area to the valve body are the same. Moreover, it became clear that the opposite direction magnetic force acting on the rear edge of the teeth was relatively large in the case of a multi-step pole type. It also became clear that the thrust of the actuator can be estimated from the magnetic force acting on the front edge of the teeth and that acting on the rear edge of the teeth.

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