A three-dimensional surface shape is produced from input numerical data. Solder banks are formed around the screw insertion holes and pressed contact with a ground connecting face on the mounting member. Thus, the through hole and the penetration pin do not interfere with each other, and thus, it is possible to set a small clearance between the through hole and the penetration pin to such a degree, while preventing a speed reducer from being in a locked state due to interference. In this example, the ARC can serve as an etch guide for selective removal of a film. In one embodiment, the invention provides a first gear, a second gear, and a ratchet mechanism having a drive body; wherein the drive body is alternately: coupled to the first gear and ratcheting with the second gear, and coupled to the second gear and ratcheting with the first gear.