Development On The Control System Of Olymball Lapping Machine For Precision Ball

Hardness material precision ball plays an important role in precision engineering field, which is considered as one of the most important elements for high precision bearing, roundness measuring equipment, gyro and other high precision machine measuring tools and apparatus. The traditional lapping technique, of which the mechanism and control is complex, the consistence and stability are poor, the machining cost is higher, makes it difficult to get hardness material ball of high sphericity. So, the application of the hardness material sphere is limited.The study in this paper is based on the basic research of a new type of lapping method for high precision ball. In order to realize the precision processing of hardness material (eg. ceramic and hard alloy, etc) ball, the control construction of wide world internet, Intranet Ethernet networks and on-site CAN bus are adopted, and then the designing of control system of hardware and software for processing in batches of precision balls lapping machine is finished. Two main control parameters of new pattern Rotated Dual-Plates lapping, including the rotation rate of internal or external lapping plate and the pressure of above lapping plate are accurately controlled. The control method based on fuzzy PID is used for the running of internal or external lapping plate, so that the control mode of low speed start-slow acceleration-accurate location is obtained, the rotating stability is lower than 5‰, and the location precision is lower than 0.4°, with the rotate speed from 2 to 120rpm. The control method based on numeral PI is adopted for pressure control of above lapping plate, and the deviation of pressure is lower than±5‰. Meanwhile, the use of expert data control system can ensure the high accuracy and quality for processing in batches, through efficiently eliminating the unsteadiness of the human operation. In the final part of this paper, silicon nitride ceramics balls (Φ35mm) are taken as object of a high efficiency lapping experiment on the lapping machine. As a result of the experiment, fine sphericity (1μm), surface roughness (Ra 50nm) of the silicon nitride ceramics balls are obtained, with the total lapping time reduced to about 1/2 of traditional loose lapping process. High processing efficiency and high quality of Lapping is realized in Rotated Dual-Plates lapping machine for precision balls.