Cutting Parameter Optimization And Experimental Research Of The Tube's Coupling In The Turning Process

Tubes'coupling plays a very important role in jointing the oil tube, higher machining accuracy is demanded in the cutting process to ensure the gas tightness of oil transport process. As tubes'coupling is a thin-walled workpiece, it's very difficult to turn the inner wall of tubes'coupling. To ensure production efficiency and safety, large clamping force is demanded in the process of turning the inner wall. But the large force often causes the roundness error out of the tolerance, leading to a high rejection rate of the products. Bao Steel has suffered a lot from this problem. To solve this problem, this paper has made researches as follows:(1) The clamping force and the cutting force model has been built through the analysis of the process of turning inner wall, and the lower limit of the clamping force also can be determined. The relation between roundness and the clamping force has been analyzed, and a theory model of the roundness has been built. (2) The cutting force has been predicted by use of the empirical formula and the finite element respectively. and Cutting force measurement experiments have been designded to verify the accuracy of the prediction.The relationship between the cutting parameter and the cutting force can be obtained through the experimental results.(3) Orthogonal experiment has been designed to make study on the relationship between the machining parameter and the roundness error of the tubes'coupling. Experimental results verify that large clamping force is the main reason for the roundness error out of the tolerance. The theory model of the roundness can be also verified.(4) A multi-objective optimizing model which aims at both minimum roundness error and peak performance has been established. Some cutting parameters such as feed and cutting velocity are taken as variables in the mode. Based on the model, the optimal cutting parameters aregenerated with particle swarm optimization. Turning experiments are carried out and the experiment result shows that the optimal cutting parameters can improve the machining accuracy while insuring the machining efficient.