Development Of The Numerical Control System For Drilling & Threading Combined Machine Based On Teaching

CNC machine has developed more than half a century, the direction of the development is becoming more composite, high precise, high-speed and modularized. With the rapid development of unitized processing technology, combined machine with its advantage of high efficiency, high precision and low cost are widely used. As the most common cutting process, drilling and threading always work orderly to finish the machining process. Conventional machine tools rely on the operator's experience in processing, the accuracy of the manufacturing workpiece cannot be guaranteed; for the CNC machine tools, operators have to program G code for the manufacturing workpiece, drilling and threading are always processing on different machine tools. So developing a set of special NC system for drilling and threading to improve processing efficiency, to save labor cost, are very important for enterprise in the transformation and upgrading.In this paper, the author designed the overall scheme of the system hardware and software platforms with HNC8 system as his basis, through combining CNC machining technology at home and abroad together, basing on control requirements of combined drilling and tapping machine CNC system and through integrating processing properties of processed products. To meet the teach-in functions of CNC machine tools, the author proposed the teach-in function implementation based on G code user macro program, which achieved the synchronization linkage of tapping feed axis and rotating spindle, as well as the hard tapping under the mode of interpolation. Based on domestic CNC system, the author designed thus achieved a dual-channel parallel control scheme numerical control system, and completed a dual-channel configuration parameters and PLC module integration. Based on the secondary development platform of HNC8 in Central China, the author developed a customized interactive interface to achieve the automatic generation of hand-taught and processing G code.Based on those studies above, the author completed the development of Numerical Control System and debugged the NCS on spot. With typical sanitary products as an example, the author had a processing verification to the products and testified the suitability of combined drilling and tapping CNC system studied in this paper, which is of great practical value.