Papers by Author: Dae Min Kang

Abstract: . It is very difficult to polish the surface of magnesium materials because of its explosion and fragility properties. Magnetic Abrasive Polishing (MAP) process is one of the nontraditional machining technologies newly developed. In the MAP process, a cutting tool that consists of ferrous particles and nonferrous abrasives under oil lubricant is flexible. Because of this flexibility, the tool can remove a very small amount of material from a workpiece and better surface can be produced after polishing the workpiece. In this study, the MAP of a magnesium material was performed. In the experimental verification, design of experimental method was performed to evaluate parameters’effect of the MAP on polishing results of the magnesium material. As a result, it was seen that the MAP was very useful for finishing the magnesium material.

Abstract: In this paper, the distribution of temperatures on specimen and the variations in punch forces on friction coefficients during press forging of AZ31 sheets have been analyzed by Finite Element Analysis technique. Results show that the top of rib and boss areas showed lower temperatures than other areas because of the heat dissipation to air by radiation. The foot regions of the rib and boss showed greater temperature rise due to greater plastic flow. The applied punch force significantly increased at 473K or lower temperatures indicating the forming temperature of AZ31 sheet should not lower than 473K. The friction condition of the punch influenced more significantly on the materials flow pattern compared to those of the die. Using a lubricant on the contact area between the punch and specimen would effectively reduce the punch force and enhance the forming capability.