A united model of diametral error in slender bar turning with a follower rest

Follower rest is an essential accessory for turning machines during the manufacture of slender bar. In order to analyze the effects of the follower rest and other machining conditions on diametral error, a united model is developed for predicting diametral error of slender bar. The proposed model consists of three components: geometric analysis of diametral error, finite element model of workpiece deflection and statistical model of cutting forces. Since there is a coupling between the actual depth of cut and the cutting force, a computer program is developed to determine the coupled depth of cut by using dichotomy. Then, a series of experiments are carried out to verify the prediction accuracy of the proposed model and a good agreement between the predicted and measured data is found. Finally, a series of numerical examples are calculated to analyze some important factors influencing diametral error of slender bar. The results show that the diametral error mainly depends on the location of follower rest, depth of cut and feed rate. But the cutting speed only has a slight effect on the diametral error.