Date of Publication :20th March 2017
Abstract: This paper describes a new, rapid servo tool system designed to produce non-rotationally symmetric components using single-point diamond turning machines. A prototype system is defined, designed for versatile interfacing with traditional machine tool controllers, as well as performance testing data of tilted flat and off-axis conic parts. Techniques are addressed to control the piezoelectric actuator to an error of less than 1 percent. The output of a regular integral controller in the actuator performance Optimization of a Fast Tool Servo for single-point diamond turning machines shows a significant error due to hysteresis. By implementing two control schemes, an optimized proportional, integral, derivative controller, and a technique using a dynamic compensator module in conjunction with the linear controller, the effects of hysteresis have been reduced. The compensator measures the relationship between hysteretic voltages, displacement in real time and thereby modifies the effective gain. Results of the simulation show that system performance errors caused by hysteresis can be compensated and reduced by 90%. Experimental implementation results in the motion error caused by hysteresis being reduced by 80 percent, but peak-to-valley errors are limited by the compensation side effects
Reference :
-
- S. Goel, X. Luo, and R. L. Reuben, “Wear mechanism of diamond tools against single crystal silicon in single point diamond turning process,” Tribol. Int., 2013, doi: 10.1016/j.triboint.2012.06.027.
- S. Goel, X. Luo, and R. L. Reuben, “Molecular dynamics simulation model for the quantitative assessment of tool wear during single point diamond turning of cubic silicon carbide,” Comput. Mater. Sci., 2012, doi: 10.1016/j.commatsci.2011.07.052.
- J. Chen and Q. Zhao, “A model for predicting surface roughness in single-point diamond turning,” Meas. J. Int. Meas. Confed., 2015, doi: 10.1016/j.measurement.2015.03.004.
- A. Mir, X. Luo, and J. Sun, “The investigation of influence of tool wear on ductile to brittle transition in single point diamond turning of silicon,” Wear, 2016, doi: 10.1016/j.wear.2016.08.003.
- J. Kumar, V. S. Negi, K. D. Chattopadhyay, R. G. V. Sarepaka, and R. K. Sinha, “Thermal effects in single point diamond turning: Analysis, modeling and experimental study,” Meas. J. Int. Meas. Confed., 2017, doi: 10.1016/j.measurement.2017.01.046.
- H. Wang, S. To, C. Y. Chan, C. F. Cheung, and W. B. Lee, “A theoretical and experimental investigation of the tool-tip vibration and its influence upon surface generation in single-point diamond turning,” Int. J. Mach. Tools Manuf., 2010, doi: 10.1016/j.ijmachtools.2009.12.003.
- L. Li, S. A. Collins, and A. Y. Yi, “Optical effects of surface finish by ultraprecision single point diamond machining,” J. Manuf. Sci. Eng. Trans. ASME, 2010, doi: 10.1115/1.4001037.