An Absolute Non-Contact Vacuum Pad with Embedded Air Bearings

In this paper, a novel vacuum pad based on CFD simulation and vortex levitation principle is proposed. To ensure absolute non-contact between the vacuum pad and the work-piece, four symmetrical air bearings are introduced and integrated into the design of the vacuum pad. In addition, the closed-loop gap control is applied to the operation of the vacuum pad, which avoids successfully the possible initial collision and maintains the desired gap between the vacuum pad and the work-piece. The vortex in-side the vacuum pad serves to levitate the work-piece while the air bearings, on the contrary, try to push the work-piece away if the work-piece comes too close to the vacuum pad. Therefore, proper function switching between the vortex and the air bearings is necessary. In this paper, a 5/3 pneumatic proportional directional control valve is utilized to switch the functions mentioned above. In the future, such a vacuum pad may find some potential application, like pick-up and transportation devices for TFT-LCD, solar energy panels, etc.