A precision polishing method for 3D-printed complex internal flow channel components with composite magnetic field control

Abstract

Advancements in 3D printing technology provide designers with unprecedented freedom, allowing them to prioritize fluid performance when designing flow channels for aerospace, biomedical, and other applications. This has led to increasingly complex geometries with arbitrarily shaped cross-sections and axial dimensional variations. However, traditional magnetic abrasive polishing processes often struggle to accurately control the trajectory and polishing force of abrasives when dealing with such complex flow channels, thereby compromising polishing accuracy. To address this challenge, this study proposes an innovative magnetically controlled polishing system. This system integrates four electromagnetic solenoid coils and two annular electromagnetic coils to generate a composite magnetic field, comprising an alternating gradient magnetic field across the cross-section and an oscillating magnetic field along the axial direction. The magnetic abrasives are driven to execute a combined motion that integrates circumferential motion with axial reciprocating motion. By establishing a mathematical model correlating magnetic field force with input current in each coil, precise control over the motion trajectory, speed, and polishing force of the abrasives is achieved. The inner walls of various complex flow channels were thoroughly polished through the combined motion of abrasive particles (with the roughness of each flow channel decreasing by approximately 50 % after polishing). Additionally, comparisons of roughness at different positions within the same flow channel demonstrated the uniformity of the polishing effect. This study confirms that the proposed magnetically controlled polishing system offers a feasible and effective solution for achieving efficient and precise polishing of the inner surfaces of complex flow channels.