자기연마를 이용한 마그네슘 박판의 평면가공 및 미세 디버링에 관한 연구

Abstract

본 논문에서는 AZ31B 마그네슘 합금 판재의 홀(hole)에 발생하는 버의 효율적인 제거를 위해 자기연마를 방법을 제안하였고, 평면에서의 자기연마 특성을 실험계획법을 활용하여 분석하였다. 그리고 그 결과를 활용하여 마그네슘 디버링 공정 특성을 평가하여 그 결론을 아래와 같이 얻을 수 있었다. 1. 비자성체인 마그네슘 합금의 디버링효율 향상을 위하여 영구자석(네오디움)을 활용한 자기력 향상방안을 제시하였으며, 약 40%의 자기력 향상결과를 얻었다. 2. 마그네슘 평판의 자기연마에서 영구자석에 의한 자기력 향상의 영향으로 공구의 회전력이 표면거칠기의 변화에 가장 큰 영향을 미치고 있음을 확일 할 수 있었다. 3. 마그네슘 디버링 공정에서 또한 회전속도가 버의 제거율에 가장 영향이 컸으며, 회전속도가 1200rpm, 입자의 종류가 Boron nitride, 전류의 세기가 1.0A 그리고 간극이 2.0mm일때 가장 좋은 버 제거율을 얻을 수 있음을 예측 할 수 있었다.

Drilling process is usually used in various manufacturing processes. The burrs took place when drilling process is conducted. Therefore the burr problem occurred from drilling process is very significant. Sometimes, burrs cause unexpected problems such as no good quality product that has a bad surface roughness. Therefore, it is important to know characteristics of burr formation and to remove the burr from the drilled material at machining process. This study aims that how to produce the better drilled products by controlling of process factors. Therefore, it is important to know characteristics of burr formation and to remove the burr in the material at machine process. In recent year, magnesium is widely used to manufacturing industry, however, the proper processing method has not reported yet. This material is very attractive in the industries. The magnesium is one of non-ferromagnetic materials. They offer a possible alternative to steel and aluminum in automotive and aero industries to satisfy the lightweight requirement. Also, magnesium has good specific strength and absorbs vibration in occurring working process. Specially, it is hard to remove burrs from magnesium plate hole by using conventional method because of natural properties of magnesium. Since the solid tools have trouble in entering into inaccessible and invisible micro-shape area, it is difficult for conventional method using solid tool to remove the burr perfectly. Solid tools may not enter into inaccessible and invisible area. In order to overcome this defect, magnetic abrasive polishing may be suitable to the restricted part of the geometry surface like micro burr of magnesium plate. So, this paper presented some experiments by using MAP machine. Evaluation of parameters on deburring process using MAP was performed using design of experiments. As a results, parameters A, C, and D affect mean and the variation in removal rate of burr height. And it seems that the level 2 parameter A(rotational speed) and level 1 parameter B(abrasive type), C (amount of current) and level 3 parameter D(working gap) may provide optimum result for beburring of AZ31 using MAP process.