Diamond grinding wheels are widely used to grind various hard and brittle materials such as glass, ceramics, semiconductors and other crystal materials. In precision optical processing, especially for large-diameter optical components, ultra-precision grinding applications are becoming more widespread. Increasing the grinding wheel speed can improve the dressing precision and dressing rate. In order to improve the surface quality of the optical glass or optical crystal and reduce the subsurface damage, the working speed of the spindle of the high precision CNC optical processing machine tool is required much higher than that of traditional vertical milling machines. However, as a high-speed rotating part, in order to minimize the vibration of the machine tool and improve the working life of the spindle bearing of the machine tool, higher requirements are necessary for the application of the diamond grinding wheel.
For high-speed rotating diamond grinding wheels, the pre-tightening force during installation also needs to be controlled. If the pressing force is small, the vibration of the diamond grinding wheel will increase due to the reduction of the grinding force. Precision optical manufacturing is closely related to precision machinery manufacturing.
The bond means that consolidates the diamond particles on the diamond grinding wheels substrate. The bond has a great influence on the service life and grinding ability of the grinding tool. Therefore, a reasonable choice of bond is important to improve productivity and surface quality of parts. At present, there are four bond types, namely resin bond, ceramic bond, metal bond, and electroplating bond. Since the working speed of the high-precision CNC machine tool spindle is very large and the grinding wheel need to bear large load during milling process and ensure the surface quality of the optical material, so the bronze in the metal bond is selected as the bond material. In general, the base of the diamond grinding wheel is mainly made of steel or copper. However, due to the high density of steel or copper, when the steel or copper is unevenly distributed or the manufacturing error of the diamond wheel occurs, great difficulty will be brought to the balance correction. After comparison, it is better to select aluminum alloy as the matrix material. The aluminum alloy is not only light in weight, but also difficult to rust, and the manufacturing cost is relatively low, and the effect is obviously superior to steel or copper in the balance correction.
As the surface quality requirements of the machined parts increase, the working speed of the diamond grinding wheel is further improved. As a high-speed rotating part, the requirements for its balance accuracy are getting higher and higher. The unbalanced value directly affects the vibration of the diamond grinding wheel and the working life of the machine tool and the milling precision of the object to be processed. Therefore, choosing a reasonable balance is especially important. Since the dynamic balance of the diamond grinding wheel cannot be corrected by the method of material removal during the milling process of the optical parts, technical measures should be taken to solve the design and processing problems of the diamond grinding wheel. In order to correct the imbalance of the diamond wheel balance to a reasonable range before the milling process, an array of threaded holes for correcting the dynamic balance can be designed on the base of the diamond grinding wheel.
Excellent grinding performance, precise machining equipment and suitable machining processes are important factors for precision grinding.