Abstract: In the current study, a reclamation module uses micro electroetching as a precision fabrication with a new design of T-form tool to remove the defective Indium-tin-oxide (TCO) nanostructure from the optical PET surfaces of digital paper display is presented in current studies. The adopted precision reclamation process requires only a short period of time to remove the TCO nanostructure easily and cleanly is based on technical and economical considerations and is highly efficient. A large rotational diameter of the cathode accompanied by a small gap width between the cathode and the workpiece corresponds to a higher removal rate for the TCO nanostructure. A small thickness of the electrodes, or a small edge radius of the electrodes takes less time for the same amount of TCO removal. A higher feed rate of the optical PET diaphragm combines with enough electric power to drive fast etching rate. High rotational speed of the T-form tool can improve the effect of dregs discharge and is advantageous to associate with the fast feed rate of the workpiece (optical PET diaphragm).
Abstract: This study proposes a tool wear automatic monitoring system based on multiple parameters analysis of cutting force and machine vision technique. A drilling model of cutting parameters (cutting force, coating layer, spindle speed and feed rate) and tool condition (focusing on tool flank wear measurement and analysis) was developed. The experimental design methods developed in this study can be used to optimize cutting parameters efficiently and reliably. The drilling model based on cutting parameters was constructed using Taguchi method. This method enabled evaluation of wear status based on the actual force obtained from a dynamometer. The derived relation is useful for in-process wear monitoring. Tool wear dynamics are extremely complex and not yet fully understood. Therefore, vision-based tool wear monitoring techniques can help elucidate wear progression. In this study, a drilling model based on the machine vision technique was used to establish a direct relation between cutting parameters and tool wear. The object of the experiments was to measure the flank wear of cutting tools with various coatings. The experimental results show that the monitoring system clarifies the relationships between cutting force and multiple cutting parameters.
Abstract: Due to the rapid development in recent cutting technology, demands for different types of precise cutting tools become increasingly complicated. Since the design and grinding of end-mills are the last and the most important processing for cutting tools. The geometrical accuracy and the cutting performance of an end-mill depend essentially on the grinding. However, the complicated geometry of an end-mill will be ground by the specific software of CAD/CAM on the 5-axis CNC tool grinding machine. The precision of end-mill grinder will be determined by the performance of 5-axis CNC tool grinder and setting of grinding parameters. Three regulation factors for grinding are grit size of the diamond grinding wheel, grinding speed and the feeding speed. The variable ranges of each parameter can be divided in large, medium and small interval. In this study for an end-mill with fixed geometrical profile, a series of different grinding parameters have been utilized by the 33 factorial experiment planning. And tool grinding experiments for the rod material specification of tungsten carbide have been performed by 5-axis CNC tool grinder. After grinding, surface roughness of tools will be measured. The reliability and precision of the end-mill grinding can be enhanced by the prediction model of polynomial network for surface roughness of end-mills. Besides, the database system for cutting tool has benn established. Totally 4802 data were constructed in the relational database according to the characteristics of tools.
Abstract: In our previous study, a new centerless grinding method using surface grinder was proposed. In this method, a compact unit consisting mainly of an ultrasonic elliptic-vibration shoe, a blade, and their respective holders is installed on the worktable of a multipurpose surface grinder to conduct tangential-feed centerless grinding operations. For the complete establishment of this new method, firstly in this paper workpiece rotational speed control tests were carried out to make sure that the workpiece rotational speed is exactly controlled by the elliptic vibration of shoe to achieve high-precision centerless grinding. Then, the effects of the process parameters such as the worktable feed rate, the stock removal and the workpiece rotational speed on the workpiece roundness were clarified experimentally. The obtained results showed that (1) The workpiece rotational speed can be controlled exactly by the shoe ultrasonic vibration, (2) The roundness is improved with the increases in the voltage applied and the stock removal, but the decrease in the worktable feed rate; The best roundness obtained was 0.84m.
Abstract: In our previous study, a new centerless grinding method using surface grinder was proposed. This paper describes a simulation method for investigating the workpiece rounding process in which a model taking the elastic deformation of the machine into consideration is created, and revealing how the process parameters affect the machining accuracy in the new grinding technique. In addition, a practice way to determine the machining-elasticity parameter showing the elastic deformation is developed. The simulation results are compared to show the effect of process parameters on the machining accuracy.
Abstract: Micro/Nanofabrication of silicon substrate based on the atomic force microscope (AFM) followed by wet chemical etching was demonstrated. A specially designed cantilever with a diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional Si or Si3N4-based micro cantilever for scanning. A thin damaged layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip, which was found to be a low crystallized amorphous silicon layer. Hence these sequential processes, called tribo nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool. According to our results, it has been clearly known that the damaged layer withstands against aqueous potassium hydroxide solution, while it dissolves in diluted hydro fluoric (DHF) solution.
Abstract: This paper discusses the feasibility of improving machining efficiency of sapphire substrate by using two-dimensional (2D) ultrasonic vibration assisted grinding. An elliptic ultrasonic vibrator is designed and produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304). The sapphire substrate is fixed onto the top face of the vibrator and ultrasonically vibrates in 2D vibration mode when the PZT is excited by two alternating current voltages with a phase difference. A grinding apparatus mainly composed of the ultrasonic vibrator is constructed, and experiments are performed with lateral modulation of elliptic ultrasonic vibration vertical to the grinding direction. Both the grinding forces and the ground work surface are measured and examined. Experimental results show that the grinding force decreases significantly and the resulted surface is improved in certain degree with the ultrasonic vibration compared to those of conventional grinding without ultrasonication. This indicates that the high efficiency grinding for sapphire substrate can be performed with the two-dimensional vibration grinding technique presented in this paper.
Abstract: Metal-bonded ball-headed diamond wheel with small diameter has been widely used in the ultra-precision grinding of optical parts, especially in the parts with complex surface. In-position precise dressing technique of ball-headed diamond wheel is the key technology to improve grinding precision. The effect of mechanical errors on the profile accuracy of wheel dressing were theoretically analyzed firstly. Afterwards a ball-headed diamond wheel dressing equipment based on electrical discharge principle has been designed and built. Orthogonal experiments have been carried out on the dressing equipment, and the dressing quality of wheels under different dressing electrical parameters were analyzed in terms of wheel profile accuracy and wheel surface micro-topography. The influence of dressing electrical parameters on the dressing quality were investigated and the best electrical parameter combination was obtained. Experimental result showed that the wheel profile accuracy can reach upward 0.8μm after dressing, and the protrusion heights of diamond grain were uniformity and the protrusion effect was better than without dressing.