Abstract: A polishing apparatus includes a polishing device, a polishing fixing device, and a controller. The polishing fixing device includes a rotating mechanism, a sensor, a movement compensation assembly, a first moving assembly and a second moving assembly. The sensor in the polishing fixing device senses pressure applied to the workpiece during polishing, the movement compensation assembly can drive the rotating mechanism to move in compensation, so as to keep the polishing pressure within a certain range for uniformity in polishing, improving the polishing quality and production efficiency of the workpiece.

Abstract: A sliding mechanism includes a hollow track and a trolley. The hollow track includes a slot. The trolley includes a first plate, a second plate and rolling units. The first plate is wider than the slot and located in the hollow track, and includes two pairs of apertures. The second plate includes two pairs of apertures, and is mounted on the hollow track. Each rolling unit includes a trough, a cover and rollers. The cover is connected to the trough through a related pair of apertures so that they together form a pod. The rollers are disposed in the pod so that some of the rollers contact a side of a related one of the plates while some other rollers contact another side of the plate and that the rollers can roll and move in the pod through the apertures. A fastener fastens the plates to each other.