| 摘要 |
PURPOSE:To eliminate the easy occurrence of step-out in case when an external force is put on, by cotrolling the supply of compressed air until the movement to the following positioning place is started after relative positioning of a fixed part and a moving part is ended. CONSTITUTION:Relative positioning between a platen 1 and a head part 2 is executed, and thereafter, when a compressed air supply quantity for forming an air bearing 3 is controlled and is reduced gradually, the platen 1 and the head part 2 reduce an air bearing gap, keeping mutually a relative position in the XY directions, and in the end, the gap is eliminated. This shows a state that permeance of a magnetic circuit formed between the platen 1 and the head part 2 becomes maximum, and its holding force also becomes maximum. In this way, when an assembly work is executed after controlling the compressed air supply quantity and making the holding force of the head part 2 maximum, even if large external force is put onto the head part and the subsequent part, the platen 1 and the head part 2 do not cause step-out, and the work can be executed exactly. |
