The Research On Tool Path Planning For Complex Parts Of Construction Machinery

In recent years, with the rapid development of the manufacturing industry, more and more complex curved surfaces are being used in automobile, navigation, ship building and electronic products, and so on. Owing to the designs of complex curved surface products are becoming more and more complex, as a result, products processing is becoming more difficult and time-consuming. With the developments of the technology and continuous improvements of the quality requirements of complex curved surfaces products, free surfaces processing technology sets higher demands for processing industry as well as a series of processing technology emerged, such as numerical control machining techniques with high-performance and the processing technologies with high speed. Numerical control machining techniques with high-performance turn into the key technology of the realization of free surfaces high-quality processing by its advantages, such as high-speed, high precision, the stationary of fine processing and the smoothness of tool path. Furthermore, numerical control machining techniques with high-performance place higher expectations to the quality of the tool path planning.Tool paths planning is one of the key problems needed to be resolved in the complex curved surfaces. Its accuracy and rationality are directly related to the maximum processing efficiency in the maximum error allowed. Firstly this paper provides the matrix representation of NURBS curves and surfaces as well as the steps of NURBS surfaces interpolation. Meanwhile the paper founds a ruled surface in the form of the blade surface. Through analyzing many kinds of curved surface machining methods, such as the iso-parametric method, the APT method, the polyhedral machining method, the method of curves of cross sections, the method of offset surface and the projection method, the line cutting method is proposed as the main tool path planning of the blade surface machining method in this paper. Based on the NC programming of impeller in Pro/NC, the vertical one-way mode, the vertical reciprocating mode, the horizontal one-way mode and the horizontal reciprocating mode are got. The influences of path interval, cutting speed feed direction and feed rate on the surface roughness are researched in the end of this paper. In addition, machining simulation of the tool path and numerical program generated by Pro/NC was given in this paper.The results show that the tool path generated can satisfy the needs of free surfaces processing with high-performance.