This study attempts to find optimal conditions of the friction coefficient using a discrete element method (DEM) simulation with various friction coefficient conditions and three different grinding media with various ball sizes in a traditional ball mill (TBM). Using ball motion of the DEM simulation are obtained using the optimal friction coefficient compared with actual motion; photographs are taken by the digital camera and the snapshot images are analyzed. In the simulation, the rotation speed of the mill, the materials and velocity of the grinding media, and the friction coefficient between the balls and the wall of the pot are fixed as the actual experimental conditions. We observe the velocity according to the friction coefficient from the DEM simulation. The friction coefficient is found to increase with the velocity. Milling experiments using a traditional ball mill with the same experimental conditions as those of the DEM simulation are conducted to verify the simulated results. In addition, particle morphology change of copper powder is investigated and analyzed using scanning electron microscopy (SEM) for the milling experiment.

Abstract
1. 서 론
2. 실험 방법
3. 결과 및 고찰
4.결 론
References

• 자갈사이항 바트체첵(창원대학교 메카트로닉스 융합부품소재 연구센터(ERC)/창원대학교 대학원 신소재공학과) | Battsetseg Jargalsaikhan (Engineering Research Center (ERC) for Integrated Mechatronics Materials and Components, Changwon National University/Graduate School of Material Science Engineering, Changwon National University)
• 보르 암갈란(창원대학교 메카트로닉스 융합부품소재 연구센터(ERC)) | Amgalan Bor (Engineering Research Center (ERC) for Integrated Mechatronics Materials and Components, Changwon National University)
• 오란치멕 쿨란(창원대학교 메카트로닉스 융합부품소재 연구센터(ERC)/창원대학교 대학원 문화융합기술협동과정) | Khulan Uranchimeg (Engineering Research Center (ERC) for Integrated Mechatronics Materials and Components, Changwon National University/Graduate School of Convergence on Culture Technology, Changwon National University)
• 이재현(창원대학교 메카트로닉스 융합부품소재 연구센터(ERC)/창원대학교 대학원 신소재공학과) | Jehyun Lee (Engineering Research Center (ERC) for Integrated Mechatronics Materials and Components, Changwon National University/Graduate School of Material Science Engineering, Changwon National University)
• 최희규(창원대학교 대학원 신소재공학과/창원대학교 대학원 문화융합기술협동과정/창원대학교 메카융합공학과) | Heekyu Choi (Graduate School of Material Science Engineering, Changwon National University/Graduate School of Convergence on Culture Technology, Changwon National University/Department of Mechatronics Convergence Engineering, College of Future Convergence, Changwon National University) Corresponding author