To determine mirror surface finishing conditions and efficient and economical superfinishing conditions for pure titanium and titanium alloys, an abrasive film is used when superfinishing is performed under varying conditions. These conditions include the workpiece rotation speed, the oscillation speed, the contact pressure of the roller, the hardness of the roller, and the type of abrasive film. The superfinishing device is applied to polishing a thin and long cylindrical bar. A micro-finishing film and a lapping film were used as abrasive films. Al 2 O 3 grains or SiC grains were used as abrasives. The surface roughness of a polished workpiece was measured using a stylus-type surface-roughness measuring instrument. As a result, the conditions to improve the polishing surface efficiently include high values for the workpiece rotation speed, oscillation speed and contact pressure. The roller hardness has no effect on the efficient polishing conditions. The mirror finish of a surface can be created using lapping film of 3 μm with Al 2 O 3 grains after polishing to a steady surface roughness under the efficient polishing conditions.
Nanowire structures have attracted attention in various fields, since new characteristics could be acquired in minute regions. Especially, Anodic Aluminum Oxide (AAO) is widely used in the fabrication of nanostructures, which has many nanosized pores and well-organized nano pattern. Using AAO as a template for replication, nanowires with a very high aspect ratio can be fabricated. Herein, we propose a facile method to fabricate a nano-micro hybrid structure using nanowires replicated from AAO, and surface treatment. A polymer resin was coated between Polyethylene terephthalate (PET) and the AAO filter, roller pressed, and UV-cured. After the removal of aluminum by using NaOH solution, the nanowires aggregated to form a micropattern. The resulting structure was subjected to various surface treatments to investigate the surface behavior and wettability. As opposed to reported data, UV-ozone treatment can enhance surface hydrophobicity because the UV energy affects the nanowire surface, thus altering the shape of the aggregated nanowires. The hydrophobicity of the surface could be further improved by octadecyltrichlorosilane (OTS) coating immediately after UV-ozone treatment. We thus demonstrated that the nano-micro hybrid structure could be formed in the middle of nanowire replication, and then, the shape and surface characteristics could be controlled by surface treatment.
In order to develop a practical postprocessor for 5-axis machine tool, the general equations of numerically controlled (NC) data for 5-axis configurations with non-orthogonal rotary axes were exactly expressed by the inverse kinematics, and a windows-based postprocessor written with Visual Basic was developed according to the proposed algorithm. The developed postprocessor is a general system suitable for all kinds of 5-axis machines with orthogonal and non-orthogonal rotary axes. Through implementation of the developed postprocessor and verification by a cutting simulation and machining experiment, the effectiveness of the proposed algorithm is confirmed. Compatibility is improved by allowing exchange of data formats such as rotational total center position (RTCP) controlled NC data, vector post NC data, and program object file (POF) cutter location (CL) data, and convenience is increased by adding the function of work-piece origin offset. Consequently, a practical post-processor for 5-axis machining is developed.
The purpose of this study is to develop a twin wheel creep-feed grinding machine using continuous dressing to machine precise axisymmetric turbine blades that have been difficult to machine using a conventional creep-feed machine. In order to develop such a machine, 3D-modeling and machine simulations were performed and a twin wheel creep-feed grinding machine was manufactured. Furthermore, the axisymmetric precision of the machined workpieces through practical machining was evaluated and the quality of the continuous dressing effect of the developed machine was established. In addition, experimental considerations for a proper dresser-to-wheel speed ratio and proper feed rate of the dresser were carried out. As a result, a twin wheel creep-feed grinding machine with continuous dressing is developed through machine simulation, manufacturing and performance evaluation. Optimum condition for the dresser feed rate is 0.3 μm/rev. In cases of large dressor-to-wheel speed ratio, grinding efficiency can be enhanced, but the surface roughness shows a conflicting trend. Developed twin wheel creep-feed grinding machine has satisfactory appraisal with regard to surface roughness, flatness, and parallelism. Satisfactory surface roughness below 0.1 μm can be obtained for the blade of aircraft. However, in order to perform precise machining, it is necessary to improve the structure of the twin wheel creepfeed grinding machine.
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