Papers by Keyword: Surface Grinding

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Authors: Dinesh Setti, Benjamin Kirsch, Jan Christian Aurich
Abstract: Visualization of work surface topography through simulations is very challenging task in grinding process due to the complexity of wheel-work interactions with a very high number of cutting points (grits). Kinematic mapping of abrasive grits on a three-dimensional wheel topography enables the evaluation of ground surface topography through simulations. In this paper, a method for generating the ground surface topography based on wheel specifications is presented. Abrasive grits size, abrasives volume percentage and their nature of distribution on the wheel surface are considered in the modeling and visualization of wheel topography. The simulation results of ground surface topographies prove the feasibility of the developed method.
Authors: Ning Ning Zhang, Chen Jiang, Zhen Zhong Wang, Yin Biao Guo
Abstract: Wedge/aspheric lens element is a combination of wedge prism and aspheric lens as a single piece component forming a decentred lens, which plays an important role in the fields of liquid crystal projection display, laser fusion, high-energy laser, satellite optical system and large astronomical telescope, etc. Wedge/aspheric lens element are primarily manufactured by CNC machining, especially 3-axis CNC grinding. This paper presents a facile tool path generation approach based on space coordinate transformation. The proposed method can be used to improve and automate three-axis Wedge/aspheric lens element machining for CAD/CAM systems. As part of the validation process, the tool paths generated are analyzed to compare with the desired part.
Authors: Ondřej Bílek, Jitka Baďurová, Jiří Čop
Abstract: In this study, the surface grinding was performed at different feed rates and depth of cuts. Grindability of engineering thermoplastics and metals was evaluated. Further, important process parameters influencing surface quality were determined using analysis of variance (ANOVA). Experimental results compared two significantly different groups of materials in order to emphasize common variables. Finally, further research directions were presented to seek for functional relation between process parameters and grindability.
Authors: Qiu Lin Niu, Guo Giang Guo, Xiao Jiang Cai, Zhi Qiang Liu, Ming Chen
Abstract: As two kinds of advanced titanium alloys, TC18 and TA19 were introduced in this paper. The machinabilities of TC18 and TA19 alloys were described in the grinding process. Grinding experiments were completed using green silicon carbide grinding wheel with the coarser 100 grit. Grinding forces and specific energy in surface grinding were investigated. And then, for studying the grinding characteristic, SEM images of the workpiece material were obtained. The results indicated that specific chip formation had the great effect on the mechanism of grinding TC18 and TA19 alloys, and the scratch was the main characteristic of surface grinding. TC18 alloy had the poor grinding performance compared to TA19 alloy.
Authors: K. Babu
Abstract: In striving to remain competitive in the global market, the concept of optimization of manufacturing processes has been extensively employed to meet the diverse production requirements. Optimization analysis of machining processes is usually based on either minimizing or maximizing certain objective functions. Recently, various non-traditional optimization techniques have evolved to optimize the process parameters of machining processes. The objective of this work is to study the effectiveness of the most commonly used non-traditional optimization methods as applied to a particular machining optimization problem. In this work, surface grinding processes are optimized using i) Particle Swarm Optimization (PSO) ii) Adaptive Genetic Algorithm (AGA) iii) Simulated Annealing (SA) and iv) Memetic algorithm (MA). Memetic algorithm used here has two variations as MA-1 and MA-2, each having the combination of PSO and SA and AGA and SA respectively. The mathematical model of surface grinding operations was adopted from a literature. A computer program was written in Visual C++ for the optimization computations. The computation results of various optimization methods are compared and it is observed that the results of PSO method have outperformed the results of other methods in terms of the combined objective function (COF).
Authors: Yong Chen, Guo Qin Huang
Abstract: Vibration during high-speed surface grinding process is one of important factors to influence surface precision of machined workpieces and lead to low efficiency of grinding machine. Process parameters are usually obtained from empirical data or reference manuals for the avoidance of serious vibration even chatter and its effect. As a result, it generally leads to low rated power of machine tool and long processing cycle. To solve the problem, designing and development on a dynamics simulation system for surface grinding with high accuracy ,which will be capable to predict a series of dynamic characteristics in time and frequency domains, such as grinding force-vibration, as well as phase/frequency characteristics, relative power spectral analysis etc is necessary and shows good application prospect. Meanwhile, the system will be used to indicate the process parameters optimization and investigate distribution characteristics of grain chip thickness and surface topography precision. In the paper, surface grinding process with diamond wheel is chosen as the study object and its dynamic characteristics are investigated. Based on studies on the comprehensive influence mechanism of regenerative chatter theory and wheel run-out rotational model on instantaneous grinding chip thickness of grain unit, analytical models of grinding force are improved. Differential equations of damper grinding vibration system with two-degree-of-freedom and a close-loop control system model with regenerative chatter feedback circle on the basis of interaction behaviors of force and vibration are built. Several relevant numerical methods are introduced to develop the simulation system of grinding dynamics. By comparative analysis on solution accuracy, steadiness and convergence of the correlative algorithms, explicit Runge-Kutta formula is identified as the best solution to simulation system modeling. On the basis of the above work, main subsystems and functional modules in the system are presented. The whole designs of framework and prototype systems are finished.
Authors: Shinya Tsukamoto, N. Nishikawa, Katsutomo Okamoto, Kazuhito Ohashi
Authors: Yan Ling Tian, Da Wei Zhang, H.W. Chen
Abstract: In order to realize dynamic control during surface grinding, a 3-DOF (degree of freedom) micropositioning table driven by three piezoelectric actuators has been developed. The monolithic flexure hinge mechanism is utilized to provide preload for the piezoelectric actuators. The table has an outline dimension of Φ150×145 mm and a working range of 12 µm. The resolution of the table is less than 5 nm and the stiffness under open loop condition is approximately up to 94 N/µm. The design of the micropositioning table is presented with consideration to achieve the high dynamic characteristics. The dynamic models of the table have been established. Experimental tests have been carried out to verify the performance of the micropositioning table and the established models.
Authors: Cong Mao, H.F. Zou, Z.X. Zhou
Abstract: The grinding forces and grinding temperature were measured by using a 3-axis piezoelectric dynamometer and a thermocouple, respectively. The morphology and roughness of the ground surface were analyzed by using a scanning electron microscope (SEM) and a talysurf. It is found that the grinding parameters have great influence on the grinding temperature. Meanwhile, the down grinding has higher temperature than the up grinding. The relation among the grinding temperature, the morphology and the roughness of ground surface was discussed. It is found that when the grinding temperature is not high enough for the ground surface to appear obvious burn, the grinding temperature has little influence on the surface roughness.
Authors: Qing Long An, Yu Can Fu, Jiu Hua Xu
Abstract: Grinding, characterized by its high specific energy consumption, may generate high grinding zone temperature. These can cause thermal damage to the ground surface and poor surface integrity, especially in the grinding of difficult-to-machine materials. In this paper, experimental and fem study on grinding temperature during surface grinding of Ti-6Al-4V with different cooling methods. A comparison between the experimental and numerical results is made. It is indicated that the difference between experimental and numerical results is below 15% and the numerical results can be considered reliable. Grinding temperature can be more effectively reduced with CPMJ than that with cold air jet and flood cooling method.
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