The Studies On Five-axis Line Interpolation Technology About Cutter Position Based On TwinCAT

Along with the development of machinery manufacturing and NC technology, there aremore and more new multi-axis machine tools, most of which have the open CNC system. Thetraditional special-purpose NC machine tool has been difficult to adapt to the development ofnew technology in many fields, such as computer technology, communication technology,flexible manufacturing technology. In the NC process, ordinary NC machine tool andthree-axis machine tool could not meet the machining requirements of some complex parts,such as impeller blades, heavy generator rotor. There are two rotation axes on the five-axisCNC machine tool, and it can process the space free surface. So it will be easy to solve theproblem in the aspect of processing complex surface. Some fields that related to five-axisCNC technology have become the important research direction for many scholars.The research of this paper is about open CNC system. It mainly studies five-axis lineinterpolation and its related algorithm. The system is based on TwinCAT and combined withVC++to control servo axis. It describes the structure of the TwinCAT software, shows thepowerful function and built the structure platform of hardware and software. The control cardFC7501is based on SERCOS bus technology, and its related technology have been analyzedin this paper.Before the process of interpolation, decoding module and cutter compensating moduleare two important parts. Coding is the basic link to realize input and output, and it can convertNC programs into the command format which can easily be identified. The NC system whichcontains cutter compensation function could adjust the change of cutter radius by setting theparameters. It doesn’t need to exchange cutter. The algorithm of cutter compensation has beenreasonable analyzed with vector projection method.Five-axis line interpolation is the most basic function of track control in the CNC system,which directly determines the process precision and surface quality. The realization offive-axis interpolation is the main research content, including the method of three-axisexpansion, the plan of speed through connection, interpolation error control, etc. There isanother important factor that it will control the process of acceleration and deceleration. The segmentation method of five phased S-curve is proposed in this paper. The process of speedchange which is according to the S curve is divided into five stages. Every stage has differentacceleration change, which is more reasonable than the traditional method. This method isproved to be practical, and it can reduce the impact of machine tool which is generated fromspeed change. The new method also can meet the process requirement of high-speed andhigh-precision. A simple user control interface is developed with the mixing programming ofTwinCAT and VC++, which is used to control the rotation of five servo axes.