Pengzi Xu

A new tool path for optical freeform surface fast tool servo diamond turning

Fast tool servo–assisted ultra-precision diamond turning has been extensively regarded to be a very promising technology for the fabrication of optical freeform surfaces, and micro- and nano-structured surfaces with high efficiency and high surface quality. This article describes a changing feed-rate tool path which can adjust the tool position arbitrarily both in the x-direction and z-direction to obtain homogenous surfaces. Meanwhile, it can improve machining efficiency, save cutting parameters calculation time, and avoid over-cutting at workpiece center. Cutting experiment is carried out to implement the new tool path.

The analysis and measurement of motion errors of the linear slide in fast tool servo diamond turning machine

This article proposes a novel method for identifying the motion errors (mainly straightness error and angular error) of a linear slide, which is based on the laser interferometry technique integrated with the shifting method. First, the straightness error of a linear slide incorporated with angular error (pitch error in the vertical direction and yaw error in the horizontal direction) is schematically explained. Then, a laser interferometry–based system is constructed to measure the motion errors of a linear slide, and an algorithm of error separation technique for extracting the straightness error, angular error, and tilt angle error caused by the motion of the reflector is developed. In the proposed method, the reflector is mounted on the slide moving along the guideway. The light-phase variation of two interfering laser beams can identify the lateral translation error of the slide. The differential outputs sampled with shifting initial point at the same datum line are applied to evaluate the angular error of the slide. Furthermore, the yaw error of the slide is measured by a laser interferometer in laboratory environment and compared with the evaluated values. Experimental results demonstrate that the proposed method possesses the advantages of reducing the effects caused by the assembly error and the tilt angle errors caused by movement of the reflector, adapting to long- or short-range measurement, and operating the measurement experiment conveniently and easily.

The Educational Reform of the “Fundamentals of Mechanical Manufacturing Technology” for the “Education and Training Program of Excellent Engineer”

This paper proposes the educational reform for the teaching content and method, the experimental teaching, the practice teaching and the examination of the “Fundamental manufacturing technology”, according to the highlights, objectives and principles of the “Education and training program of excellent engineer”(Excellent Program). The students have gotten a better understanding of the FMT course, and their practical and innovative ability have been enhanced, through the reform measures. KEYWORD: Excellent Program; Fundamentals of Mechanical Manufacturing Technology; Educational Reform International Conference on Social Science, Education Management and Sports Education (SSEMSE 2015)

A Quasiphysics Intelligent Model for a Long Range Fast Tool Servo

Accurately modeling the dynamic behaviors of fast tool servo (FTS) is one of the key issues in the ultraprecision positioning of the cutting tool. Herein, a quasiphysics intelligent model (QPIM) integrating a linear physics model (LPM) and a radial basis function (RBF) based neural model (NM) is developed to accurately describe the dynamic behaviors of a voice coil motor (VCM) actuated long range fast tool servo (LFTS). To identify the parameters of the LPM, a novel Opposition-based Self-adaptive Replacement Differential Evolution (OSaRDE) algorithm is proposed which has been proved to have a faster convergence mechanism without compromising with the quality of solution and outperform than similar evolution algorithms taken for consideration. The modeling errors of the LPM and the QPIM are investigated by experiments. The modeling error of the LPM presents an obvious trend component which is about ±1.15% of the full span range verifying the efficiency of the proposed OSaRDE algorithm for system identification. As for the QPIM, the trend component in the residual error of LPM can be well suppressed, and the error of the QPIM maintains noise level. All the results verify the efficiency and superiority of the proposed modeling and identification approaches.