Study On The Tool Path Planning Based On STEP-NC

STEP-NC(ISO14649) is a new NC programming standard system that proposed for computer numerical control (CNC) by the international organization of Standardization Technical Committee ISO184th first technical committee (ISO/TC184/SCI). STEP-NC is an extension to the STEP standard.It will develop the process into a series of processing steps,and each step can be performed on a CNC machine.The processing steps in STEP-NC are sent to CNC for processing instruction which is similar to G code, while the different thing is that the processing steps in STE-NC contains three-dimensional geometric informations, the tool requirements, as well as the feature definition and other mformations.Machine will make intelligent processing according to these informations. First the development of NC technology is reviewed,and then the development of evolutionary process of NC programming technology and NC system is mentioned. The limitation of the ISO6983standard is analysised,and the concept of new generation STEP-NC standard is introduced.In this paper a discussion about the standard and architecture of STEP (ISO10303), the contents of STEP-NC system structure has been made.Besides there is a introduction about each part of the contents of the ISO14649. On this basis, the tool path planning method based on STEP-NC is introduced in this paper, and the path generation method of hole and plane and other basic machining features is introduced. For CAM module based on STEP-NC used in circuit board engraving machine, because of the Gerber file data characteristics, which defined the characteristics different from general machining features,a new algorithm was proposed to generate machining path when got the profile.A CAM module was made in Visual studio editing environment with C#language.To show the CAM works well, a selected circuit board sample was used to generate the virtual machining path,and proved the feasibility of the algorithm.