Reducing the Surface Roughness of 304 Stainless Steel Powder Bed Fusion Manufactured Oil Granting Nozzles Through Polishing with Low Melting Point Alloy: Numerical Simulation and Parameter Optimization

Aiming at the finishing machining difficulties of metal parts with internal cavity walls and apertures in the equipment manufacturing industry, the study proposes a polishing method with In ₂₁ Sn ₁₂ Bi ₄₉ Pb ₁₈ low-melting-point alloy abrasive. First, the oil-granting nozzle made of 304 stainless steel powder bed fusion technology is taken as the research object, and four key parameters, namely, pressure of inlet, kinematic viscosity, strength of magnetic, and system temperature, are introduced by combining numerical simulation of computational fluid dynamics and orthogonal experiment. The results of the study show that the optimal combination of processing parameters is the kinematic viscosity of 1.5 Pa·s, magnetic field strength of 40 A/m, inlet pressure of 4 MPa, and system temperature of 80°C. Under the optimal processing parameters, the surface roughness in the region for the oil-granting nozzle’s small hole region was reduced to the level of 0.13 μm.