박판 마그네슘 합금의 성형성에 관한 연구

Abstract

Sheet metal forming method is to make various forms of products by using Sheet metal. In economical aspect, we can produce a large scale of product with low cost as the loose of raw material is considerably minor and required time to produce is rather short, and in a view of products, it has excellent intensity considering it's weight and the feature of surface is superior. Thus sheet metal forming method is widely applied in manufacturing vehicles, airplanes, and in electrical parts, etc. Sheet metal forming method, however, consists of various and complicated process including drawing, bending, stretching and trimming, etc. using sheet metal. Therefore, during the forming, various types of problems like crack, wrinkling and spring back, etc. depend on the material's mechanical characteristic and forming condition. To make excellent quality products without these types of physical defects, a reasonable design for process is essential. General methods to decide process variables is to do in an empirical way personally. But this method is very inefficient because it must get through lots of processes of trial and error. Due to the development of computer, recently, analysis of the forming process with numerical method became possible. In reality, computerized software for forming analysis is available and widely utilized in the industrial field. The characteristic of magnesium alloy is the most light in utility metal, the effect of electromagnetic wave interception, excellent specific strength and absorptiveness of vibration. Although magnesium alloy with above characteristic is a subject matter which is suitable in world-wide tendency of electrical component frame, sheet magnesium alloy is difficult to process. Therefore, forming analysis of sheet magnesium alloy and applying warm-working to process are indispensable. Among Finite Element Methods, the static implicit finite element method is applied effectively to analyze sheet magnesium alloy stamping process. In the way of static implicit analysis, there are one-step analysis method and incremental analysis method. But in order to apply to the production process which is requiring considerably short lead time, the one-step analysis needs to be used in advance. One-step analysis is rather low in its' accuracy. But because the analysis time is so short, it has an advantage to find out the design and process variables in early stage to provide the direction of process. Meanwhile, the incremental method guarantees the high accuracy through the process of sequential analysis. However, its processing time is significantly slow compared to the one-step method. Therefore, It is the most efficient to use both incremental method and one-step method in the industrial field. In this study, it was focused on the crack, wrinkling and spring back on the stamping of magnesium alloy sheet by using the static implicit analysis. According to this study, the results of simulation will give engineers good informations to access the forming technique on sheet magnesium alloy. And its application is being increased especially in the production of electrical component case for using of the magnesium alloy.