Princip dvostrukog / jednostrukog površinskog lapinga
The flatness of the lapping plate can be automatically corrected by trimming gears, the lapping amount is controlled by the text display. equipped with frequency conversion motor, the machine tool start and stop are stable, and the ideal lapping speed can be selected. The structure of the double surface lapping machine includes two lapping plate, carriers, four motors, sun wheel, trimming gear, etc. In comparison, the structure of the single surface lapping machine is relatively more complicated, but the efficiency of the double surface lapping machine is double of the single surface lapper, if the workpiece needs to be polished on both sid The working principle of the double /single surface lapping machine: the upper and lower lapping plate rotate in opposite directions, and the workpiece keeps revolution and rotation in the carrier. The polishing resistance is small and does not damage the workpiece, and the working efficiency is high because of the uniform lapping on both sides. In addition, There is a grating thickness control system, and the thickness tolerance of the processed workpiece can be controlled. The double surface lapping machine that equipped with coated/embedded abrasives lapping tool is used to lapping the two sides of workpiece and it can simultaneously lapping and polish the two sides of the workpiece; let's take a look at the processing method of the double surface lapping machine: 1. Dry grinding: only a small amount of lubricating additive is applied to the surface of the lapping tool during processing. The sand particles are basically fixed on the tool during process, and its function is mainly sliding grinding. The efficiency of this method is not high, but it can achieve wonderful processing accuracy and a small surface roughness value (Ra0.02～0.01μm). 2. Wet lapping: In the lapping process, the lapping paste is applied to the lapping tool, and the scattered abrasive is used for lapping. besides of the abrasive, there are kerosene, engine oil, oleic acid, stearic acid and other substances in the lapping paste. During the lapping process, some abrasive exist between the lapping plate and the workpiece, as shown in Figure 8-12b. in this type of lapping, the abrasive are mainly used for rolling grinding, and the efficiency is high. The achieved surface roughness is Ra0.04～0.02μm, it is generally used for rough processing, and the processed surface is generally gray. 3. Soft abrasive grinding: During lapping, the lapping paste which using chromium oxide as the abrasive is coated on lapping plate. Since the abrasive is softer than the lapping plate and the workpiece, the abrasive is suspended between the workpiece and the lapping plate during the lapping process. The chemical interaction between the abrasive and the surface of the workpiece produce a very soft oxide film, and the film at the bumps is easily worn out by the abrasive.