Development of a magnetically driven abrasive polishing process for additively manufactured copper structures

Advances in manufacturing techniques have pushed the boundaries on many technological fronts such as semiconductor, biomedical, thermal management, and vacuum devices industries. Recent improvements in additive manufacturing have allowed the production of complex three-dimensional structures using polymers, metals, ceramics, or the combinations of these materials. However, surface roughness remains a critical bottleneck in these processes. High surface roughness limits the use of additively manufactured parts in applications requiring smooth surfaces. Various conventional polishing techniques have been used for additively manufactured external surfaces; however, polishing of enclosed surfaces, such as complex channel networks, still remains an unresolved issue. The goal of this study is to tackle the challenge of surface roughness in additively fabricated metal structures by developing a process that can polish external, as well as internal surfaces. Thus, a versatile process based on magneto-rheological fluid finishing is developed for this purpose. The process is developed and optimized using copper structures fabricated through electron beam melting. Preliminary polishing results show an immense improvement of surface roughness, reducing it from a mean surface roughness (Ra) of approximately 35μm and to 4μm.