Study On Auto-programming Technique In CNC Form Grinding Of Spiral Surface

In this paper, a new method about form grinding is discussed which is used to manufacture screws. At the present time, the technique of form grinding with grinding wheel dresser which can dress the grinding wheel with a complex curve has not been used domestically. In order to improve the machining precision and efficiency of screw compressor rotors, form grinding manufacture techniques of numerical control is studied and analyzed in this paper. A new method of machine controlling and a technique of form grinding with lower cost and higher flexibility are raised in this paper and a serial of crucial problems about it is settled in this paper.In this paper, the theory of formed cutter for curved face of screw is discussed. The data of the end face and some related parameters about screw is used with the numerical method, and at last the profile of the grinding wheel is calculated. In this paper, the choice principles of some important parameters such as established angle and central distance between the grinding wheel and the screw are discussed. Some problems are also treated with such as the phenomenon of the profile break and cuspidal points which appear possibly. The error of the result data is analyzed in this paper.The problems for controlling continuous dressing of the grinding wheel in form grinding processing are studied in this paper. Because of dressing data changed according to the dressing amounts in the process of dressing, it needs to update the numeric programs for dressing process and compensate the decreasing of grinding-wheel's diameter. The process is complex because of the calculation and controlling, and it is difficult that such a process is run at a common CNC system, so the PC is used to complete such a complex process. With the PC, the calculation of the grinding wheel profile and CNC code are completed. Then the DNC controlling method is take used of with the PMAC to control the movement of dressing device and machine tool. And CAM software is developed to control such a process. At the same time, PC can record the state of each manufacturing process in order to avoid the inconvenience because of the data lostresult from the power off. All functions above are integrated in this software which runs on computer, and the request of the automation can be satisfied practically.hi this paper, a serial of new methods for machining screw compressor rotors and controlling the grinding wheel dressing in phase are settled and a suit of CAM software is generated for calculating the profile of grinding wheel, displaying of graphics, generating and updating the CNC code, and controlling the process of machining and dressing. With the software, the theory of form grinding for screw can be used practically. It not only improves the efficiency of the manufacturing precision of screw, but also meets the satisfaction of the manufacturing automation.