Research On The Prior Fairing For NC Code

The prior fairing for NC code is a new task in Numerical Control. The tool path is arranged by NC codes inputed into CNC machine, and the prior fairing of the tool path in the tolerance can improve the manufacturing quality of the workpiece surface. Therefore, there is a practical and theoretical claim to the prior fairing for NC code.Based on the analysis of some non-fair NC codes and the description of four classical methods of curve fairing, two new fairing methods for NC code are presented in this thesis: (1) a fairing method for NC code based on the minmax approximation line. A convex hull of the planear line or arc tool path is computerd at first, and the minmax approximation line of this convex hull is calculated by the rotating capiler algorithm, At last, a decition is made to fairing those NC codes if these line and arc codes are substituted by the minmax approximation line according to the minmax length of the convex hull is less than the tolerance. (2) an improved partial fairing method for NC code by the discrete curvature. At first, bad nodes are selected by the variety of these curvatures in the line or arc path in NC code, and then the dispersed energy algorithm makes a modification of these bad nodes' position.The main results in this thesis as follows:1. State the requisition of this research and three prior fairing methods for NC code used in related CNC equipment companies at home and abroad.2. State that fairing for NC code is similar to curve fairing, and introduce the concept of fairing, fairing criterion and four classical fairing methods.3. Present a fairing method for NC code based on the minmax approximation line and validate it by a simple example.4. Present an improved partial fairing method for NC code by the discrete curvature and validate it by a simple example.