Research And Development Of A CNC System For Incremental Sheet Metal Forming

Incremental sheet metal forming is a new rapid and flexible sheet metal forming process. In the process, instead of conventional global forming, complex sheet metal is dispersed into micro-units with digitally and formed layer by layer with CNC forming machines. It has the advantages of non-die, good adaptability for the shape of forming parts and therefore can shorten the development cycle of products and reduce expenditure greatly when it is used for the new products developing, such as automobile. It can also be used for the forming of diversification and complicated shape sheet parts in small volume in the fields of space-flight and light industry.In the thesis, according the principle and requirements of incremental sheet metal forming and the idea of Open CNC System, a CNC system for incremental sheet metal forming is designed and developed based on IPC and PMAC (Programmable Multi-Axis Controller).Following are the thesis's main contents and achievements:(1) After the analysis and comparision of popular structures of open CNC systems, an open architecture CNC system with master-slave structure is schedualed for incremental sheet metal forming;(2) According the functions and electrical characteristic of PMAC, the hardware of the CNC system is designed, including the electrical control system and the interface between CNC and the electrical control system, a PLC module is also expanded and so on ;(3) With the idea of software engineer and modularized program, the software of the CNC system is divided into several modules, and programmed with VC++, including the modules of communication between IPC and PMAC, NC code translation, motion controlling and embedded PLC and etc.;(4) For the position servo control of the CNC system, fully utilizing the functions of PMAC, a PID and feedforward compound control system is used, and the parameters of PID and feedforward controller are tuned under the guidance of related control theory; Finally, the designed CNC system is tested in an incremental sheet metal forming machine; the result shows that the main functions of the CNC system can meet the expected design demands well.