Development Of Turning Servo And Cutting Force Measurement For Free-form Surface

Fast tool servo (Fast tool servo, FTS) is a lathe auxiliary processing technology, which is placed in additional guide slide plate of the turning machine. The FTS is driven by one or more high-frequency linear actuator, to achieve flat or spatial reciprocating movement. FTS has a wide range of applications in manufacture of the free-form surface. It has three application areas:the compensation of machining error; the manufacture of Rotation asymmetric free-form surface; the manufacture of shaft parts or functional micro-surface structure. In the process of the application of FTS, the extraction of cutting force signal becomes more important. To effectively improve the performance of equipment and quality of the workpiece, to explore the material removal process, to monitor the tool wear phenomenon, the reasonable modeling and accurate measurement of the cutting force is much important. The FTS technology is much different from the ordinary turning for its changing chip thickness. The premise of the study fo the cutting force is the accurate measurement. In order to solve the above problems, this paper developed a dual-axis force transducer-integrated fast tool servo(DFT-FTS), which is applied by dynamic compensation to improve measure accuracy. In the paper the following work has been done.Firstly, a cutting force model is proposed. It has considered the cutting tool nose radius and clearance angle. The relationship between the stagnation point angle and the friction angle is studied. The uncut chip thickness is modeled by minimum energy.Secondly, a dual-axis force transducer-integrated fast tool servo(DFT-FTS) is developed in this paper. Two groups of symmetrical parallel Right circle flexure hinges are used to guide the device. The piezoelectric stack is used as driving unit. The stiffness difference of the leaf spring flexure hinge in two vertical directions is used to decouple the crosstalk of the measurement in two different directions.The dynamic compensation methodology is systematically analyzed. The spectral analysis in frequency domain and multi-direction is the most suitable way to compensate the error of the DFT-FTS. The experiment of the The theoretical maximum stroke, stiffness, Minimum resolution and the error after the dynamic compensation has been done. In the last the online cutting is done in the turning machine.