Research On Flank Milling Of Free-form Surface Using Cylindrical Tool Based On Least Squares Principle

With the constant development of global manufacturing industry, five-axis NC machining get a wide range of applications in manufacturing the complex form surface. Five-axis flank milling are receiving more and more attention nowadays due to its high processing efficiency, and high quality finish surface. However, because of the character of flank milling itself, its application in the actual processing still have many limitations. Now the commonly used CAM software provides the developable ruled surface tool path planning algorithms, and in recent years for non-developable ruled surface tool path planning algorithms has made great development, but for other relatively complex free-from surface requires the designers to research the corresponding tool path planning algorithms. It greatly increases the difficulty of flank milling processing in practice application, and it also restrict the development potential of five-axis machine tools.This paper’s target is to find a kind of suitable flank milling tool path planning algorithm for free-form surface using cylindrical tool. Based on the predecessors’ research results, try to enlarge the range of 5-axis flank milling’s application. The main content of this paper include:Firstly, based on the research of flank milling tool path planning algorithm for non-developable ruled surface, we provide a tool path planning algorithm for non-developable ruled surface based on the least squares principle. The algorithm takes mapping curve as a link, by calculating the distance between the mapping curve and the design surface to describe the processing error of each tool path. The least square principle approximation model is set up, and Levenberg-Marquardt method is used to solve this optimization problem. And compared with other tool planning algorithms, a numerical example shows that this algorithm has a certain advantage.Secondly, we try to apply least squares principle algorithm to the free-form surface and analyze the machining error of free-form surface. Then we try to divide free-from to several sub surface, using the least squares principle algorithm for each sub surface respectively. We found that processing error decreases obviously by a numerical example calculation. This algorithm expand the application range of the least squares principle algorithm. It also provides significance reference for expanding the application scope of flank milling.Finally, according to different characteristics of different free-form surface, we put forward two division method for free-form surface:piecewise division algorithm and division algorithm based on isophote. Both algorithm take the subsequent flank milling machining error estimate into account, and the cutter interference, arrangement situation, robustness and the amount of calculation are also discussed. Then we analyzed the limitations, advantages and disadvantages of these two algorithms of free-form surface division.