Papers by Keyword: Diamond Cutting Tool

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Authors: Yoshikazu Arai, T. Asai, Sayeda Ferdous, Wei Gao
Abstract: This paper describes an atomic force microscope (AFM) based instrument for 3D edge profile measurement of single-point diamond cutting tools. The instrument is composed of an AFM unit and an optical sensor for alignment of the AFM probe tip (silicon cantilever) with the diamond cutting tool edge. In the optical sensor, a laser beam from a laser diode along the Y-axis is focused to generate a small beam spot with a micrometer-order diameter at the beam waist, and then received by a photo-detector (photodiode). The tool edge top and the AFM probe tip are brought to the center of the beam waist in the XZ-plane through monitoring the variation of the photodiode output, respectively. Consequently, the AFM tip can be aligned with the tool edge top. Alignment experiments and 3D edge profile measurements of a round-nose type single-point diamond tool are carried out.
Authors: Ning Yang, Zeng Qiang Li, Wen Jun Zong, Tao Sun
Abstract: The practice shows that complex lapping motion trajectory can decrease the adverse effects caused by the lapping direction which has a great influence on the lapping of the natural single crystalline diamond cutting tool. For example, addition of a reciprocating motion can get better lapping performance and surface roughness. On some kinds of natural diamond cutting tool lapping machines a further improvement is made by designing an additional planetary spindle to provide planetary motion to the main shaft, which offers a more complex motion trajectory. With an increase in degrees of freedom of the lapping machine, it becomes difficult for technicians to master a good suit of motion process parameters. This paper proposes a set of methods to plan the lapping trajectory with respect to the machine that can perform complex lapping motion. Firstly, the proposed method designed a statistical parameter which is the variance of the direction angle distribution for the lapping velocity and its calculation method to evaluate the complexity of the trajectory. And then the multi-body kinematics model was established by using Simulink tool box in Matlab software for the purpose of model kinematics simulation and outputting data for calculation of the statistical parameter above. Finally, the genetic algorithm was used to find the best motion parameters of every shaft under certain restrictions. The advantage of the set of lapping trajectory planning method presented in this paper is that it combines the powerful multi-body simulation and signal processing ability of Simulink tool box and the characteristics of the genetic algorithm in almost no limitation on awaiting optimization function and suitable for complicated problems. So the method provides not only a way for planning complex diamond lapping trajectory but also a general approach to solve the problem on machine motion process parameters optimization.
Authors: Seung Yub Baek, Woong Kirl Choi, Young Jae Choi, Eun Sang Lee
Abstract: Micro/nanoscale diamond cutting tools used in ultra-precision machining can be fabricated by precision grinding, but it is hard to fabricate a tool with a nanometric cutting edge and complex configurations. High-precision geometry accuracy and special shapes for microcutting tools with sharp edges can be achieved by focused ion beam (FIB) milling. However, in the FIB milling process, the surface properties of the substrate (such as a diamond substrate) are affected by the amorphous damage layer caused by the FIB gallium ion collision and implantation and these influence the diamond cutting tool edge sharpness and increase the processing procedure. In this study, to reduce the diamond cutting tool edge sharpness and processing procedure, FIB milling beam current and tilting angle characteristics of single-crystal diamond were investigated, along with method for decreasing the FIB-induced damage on diamond tools by platinum (Pt) coating on the diamond substrate. Experimental results revealed that optimize beam current, tilting angle and platinum (Pt) coating could lead to relatively few processing procedure and sharp cutting tool edge. The obtained results are an endeavor to enhance the controllability of the diamond cutting tool FIB milling.
Authors: Xing Gao, Chao Jiang Li, Yong Li, Cam Vinh Duong
Abstract: For reducing diamond tool wear in ultra-precision cutting of ferrous metals, a process of combining ultrasonic elliptical vibration with graphite particle atmosphere was put forward. An experimental setup was built integrating an ultrasonic elliptical vibration mechanism with a jet lubrication device on a 4-axis ultra-precision lathe. The frequency of ultrasonic elliptical vibration is 38.36 kHz with a trajectory of 8.5×3.5μm. Graphite particles with sizes of 1.3~2μm were selected. Conventional cutting and the combined method were conducted on die steel. Compared with conventional cutting with a wear land width of about 300μm, diamond tool wear in the combined method was decreased to about 20 to 30μm. The combined method is feasible to further reduce the diamond tool wear when cutting die steel.
Authors: Z.Q. Li, Tao Sun, Wen Jun Zong, Xue Sen Zhao, Shen Dong
Abstract: The nose roundness is one of the most important indexes of lapping quality of rounded diamond cutting tools. Due to its special characters and requirements, a new measuring method was proposed based on atomic force microscope (AFM) and precision-revolution spindle. However, in the measurement the alignment errors of tools with the spindle axis have great influence on the measuring result. By a carefully deducting, the relations between the deviation and the alignment errors were presented. The deviation increases with the eccentric linearly, and has the same value with the eccentric. But it varies with θ dramatically and forms a parabola curve when the deflection angle is negative, otherwise, varies with θ gently and forms a flat Gaussian curve.
Authors: Zeng Qiang Li, Tao Sun, Yong Da Yan, Jun Jie Zhang, Ying Chun Liang, Shen Dong
Abstract: Molecular dynamics is a rapidly developing field of science and has become an established tool for studying the dynamic behavior of material machining. A three-dimensional molecular dynamics (MD) model about the atoms of the diamond cutting tools and the diamond grits is built by using the molecular dynamics. The Tersoff potential function is used to calculate the force and potential energy among the atoms of the diamond tools and the atoms of the diamond grits. The lapping processes at a special cutting depth are simulated. The variety of the specimen potential energy in the lapping process is observed. The mechanism of the diamond micro machining and the form of the surface formation are given by comparing the distribution maps of atoms in initial and cutting states. This study will give a strong support to the diamond cutting tools’ lapping.
Authors: Gai Ma, Qiang Wu, Hong Jun Ni, Yi Dan Zhou
Abstract: High temperature and high pressure (HTHP) and chemical vapor deposition (CVD) are two important methods of preparing diamond. This article briefly introduced the kinds of diamond cutting tool materials and the two technologies of synthesizing diamond. And in the end, the developing trends of diamond cutting tool materials and the preparation technologies were forecasted.
Authors: Yi Dan Zhou, Gai Ma, Xiao Dan Chen
Abstract: With the improvement of machining technology, diamond cutting tools are used more and more widely due to the excellent performance of diamond. This document briefly introduced the diamond cutting tool materials and the synthetic technologies, as well as the types of diamond cutting tools. Development situation of methods of machining diamond cutting tools and the grinding technology were also expounded. At the end of the dissertation, summery and future trends of diamond cutting tool technologies were outlined.
Authors: Zheng Qiang Li, T. Sun, L.Q. Shi, Shen Dong
Authors: Wen Jun Zong, Dan Li, T. Sun, K. Cheng, Ying Chun Liang
Abstract: A brittle-ductile transition lapping mechanism is proposed for the mechanical lapping of ultra-precision diamond cutting tools, and then the critical depths of cut for brittle-ductile transition in different orientations and on different planes are deduced in theory. Combined the critical lapping depth with the contact accuracy between rotating scaife and lapped tool surface, the influences of processing factors on cutting edge radius are studied. Both the theoretical analyses and experimental results indicate that the vibration of lapping machine tool and surface quality of scaife have enormous influences on the sharpened cutting edge. And lapping compression force has an optimal value. Lapping rate should be considered when lapping velocity is selected. But the smaller the lapping velocity is, the littler the cutting edge radius sharpened. Finally, the optimal selections are performed for each influencing factor and a perfect diamond tool is lapped in ductile mode with a cutting edge radius of 30~40nm and a surface roughness Ra of 0.7nm.
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