Jong-Dae Hwang

A Continuous Control of Cutter Posture Change for Efficient 5-Axis Machining of Impeller

In 5-Axis Machining of impellers, interference problems with tool and neighboring surfaces often take place due to the narrow and deep gap between blades, so the problem of avoiding interference is very important. Also, because the efficiency of turbo machines can be maximized only when fluids smoothly flow due to the characteristics of the impeller, high quality of the machined surface is required. During 5-Axis machining of these impellers, the excessive local interference avoidance, necessary to avoid interference, leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to increase the efficiency of 5-Axis Machining of impellers, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. This study, by using an MC-space algorithm for interference avoidance and an MB-spline algorithm for continuous control, is intended to create a 5-Axis machining tool path with excellent surface quality and economic feasibility; finally, this study will verify the effectiveness of the suggested method through verification processing.

The Determination of Efficient Super Finishing Conditions for the Mirror Surface Finishing of Titanium

Recently, the demands for superfinishing machines have increased, but the development of superfinishing devices and superfinishing technology remain insufficient. And titanium, with its infinite potential, is widely known as a highly ideal material. It is therefore used in various industries that require precision-machined parts, such as the automobile, chemistry and aerospace industries, due to its outstanding specific strength and corrosion resistance compared to any other alloys. In this study, a series of experiments was performed to determine the mirror surface finishing conditions of titanium as well as efficient superfinishing conditions that can be utilized practically and economically at production sites. The applied conditions were the workpiece rotation speed, the oscillation speed, the contact pressure, the roller hardness and the type of abrasive film used when superfinishing was performed using an abrasive film for titanium-based materials such as pure titanium and titanium alloy. From the experiments, it was confirmed that efficient superfinishing conditions and mirror surface finishing conditions were determined for pure titanium and titanium alloy.