The Numerically Controlled Reforming Of The CA6140Lather Based On Machining For Variable Pitch Screw

Variable pitch screw parts are widely used in rubber, plastics, food and other industries fields. However, its application is limited by poor manufacture technics and difficulties in process using common lathes. By numerical control transformation of the engine lathe CA6140, it can solve the machining problem of variable pitch screw very well. But common tool machine can not adapt to a multi-specification and small-batch processing requirement, but considering investment cost, the continuous of the industry can not be eliminated right away.The numerical control machine contains advanced techniques, such as numerical control, micro-electronics, automatic examination, etc. It is most suitable for processing parts of small batch, high accuracy, various shapes and short productive cycle. No adjustment is necessary for the machine tools while changing to process target, which can therefore meet the processing requirement for production variety well.The main line of this paper is the design of the electronic control system in numerical control transformation of the engine lathe CA6140. The paper starts with the design of the overall scheme, makes an intensive research and exploration on applications of numerical control technology to numerical control transformation of the engine lathe CA6140, and forms corresponding technical schemes and essentials. The main contents are:1. The characteristics and processing methods of the variable pitch screw are analyzed. The processing of the variable pitch screw is determined as numerical control transformation of the engine lathe.2. On the basis of analysis and contrast of numerous numerical control systems at home and abroad, the domestic Huazhong NC system of HNC-21series is chosen as the core of the reformed CNC system. This NC system has low cost, easy to operate, efficiency, quick response and other advantages.3. During the transform process, a frequency converter and an encoder with testing function are adopted as a spindle system. In transform of the longitudinal and lateral feed, the feed box and slide body of the engine lathe CA6140are removed, and the fixed bearing of the polished rod and the end are also removed. Instead, the method that roller-screw pairs are fixed on slide body is adopted. The original saddle is removed and converted to automatic detective Hall component saddle, for purpose of saddle location, accurate transposition and high efficiency.4. The connection diagrams of NC system are designed in detail. The pin diagrams, the connection diagrams and so on, combined with all parts of execution components, are analyzed in detail. The electrical principle diagram of the original engine lathe is presented according to reformation characteristics of its components. The research have designed the main circuit diagram, the saddle control section circuit diagram, the spindle control section circuit diagram, the detailed circuit of system which is over range and limited.