目的 解决磨粒流加工3D打印制造的TC4钛合金膝关节时存在配合端面抛光效率低以及表面质量不均匀的问题。方法 运用FLUENT软件并结合非牛顿流体的Carreau-Yasuda方程对有、无仿形工装的磨粒流加工3D打印膝关节进行对比分析，研究仿形工装对磨粒流加工的影响规律，并通过单因素实验确定颗粒直径倍数与流道间隙大小的关系，从而完成最佳仿形工装设计。结果 仿真对比分析结果表明，仿形工装有助于减小压力损失，并且膝关节表面的切削量显著提升，最大提升了182.92%。同时，在双向磨粒流工艺下，膝关节表面切削量的不均匀程度平均降低73%，提升了表面质量的均匀性，证实了仿形工装的有效性。加工结果表明，当仿形流道间隙大小为5倍SiC颗粒直径、工作压力为2 MPa、加工时间为45 min、使用双向磨粒流工艺时，3D打印膝关节的整体表面粗糙度显著降低，平均表面粗糙度为0.67 μm。主要配合曲面呈现镜面效果，表面粗糙度达0.38 μm与0.46 μm。结论 当仿形工装的流道间隙为5倍SiC颗粒直径时，磨粒流抛光效果最优。采用双向磨粒流工艺，获得了优于单向磨粒流工艺的均匀表面压力，从而有效提升了表面质量的均匀性，为3D打印钛合金人工骨复杂曲端面的光整加工提供了理论参考和实验依据。

As a medical implant device, 3D printed titanium alloy knee joint is a typical complex curved workpiece. The selective laser melting (SLM) technology was used for manufacturing. The manufacturing material is the most commonly used medical grade five titanium (Ti6Al4V, TC4) in SLM technology. It is difficult to machine high-performance titanium alloy material, and it is difficult to efficiently process 3D printed titanium alloy knee joints with traditional processing. The aim of this article is to propose a method of coping flow channels, design and manufacture a knee joint imitation fixture, and use abrasive flow machining technology to efficiently process 3D printed titanium alloy knee joints. Firstly, a simulation feasibility analysis was conducted on the direct use of abrasive flow machining for 3D printed knee joints using FLUENT software combined with the Carreau-Yasuda equation of non Newtonian fluids. The analysis results showed that direct machining of knee joints had problems such as large surface pressure loss and low machining efficiency, and lower pressure at the outlet position could cause contour deformation and other problems in the actual machining process. To solve the low efficiency in direct machining of knee joints using abrasive flow, an imitation fixture was proposed. The relationship between particle diameter multiple and channel gap size was determined through single factor experiments. The best effect was achieved when the channel size was 5 times the SiC particle diameter, with a maximum reduction in roughness of 62.5%. Based on the experimental results, an imitation fixture was designed. Then, FLUENT software was used to compare and analyze the abrasive flow machining of 3D printed knee joints with and without imitation fixtures. The Preston formula was used to analyze the cutting amount of the four surfaces of knee joints with and without imitation fixtures. The results showed that the overall cutting amounts of surfaces A, B, C, and D under the imitation fixture were 81.19, 78.72, 51.33 and 52.60 MPa.m.s?1, respectively. The cutting amounts increased by 126.38%, 116.38%, 104.22%, and 114.33% compared with the surfaces without imitation fixtures. The simulation results showed that under the same pressure, the use of imitation fixtures could effectively improve machining efficiency. At the same time, the bi-directional abrasive flow process improved the uniformity of cutting amount and reduced the average fluctuation of cutting amount on the surface of knee joints by 73%, confirming the effectiveness of the imitation fixture. Finally, with a flow channel size of 5 times the diameter of SiC particles, a working pressure of 2 MPa, a processing time of 45 min, and a bidirectional abrasive flow process, the TC4 knee joints were subject to abrasive flow polishing using a glass fiber composite nylon powder printing imitation fixture. The overall roughness of the 3D printed knee joints was significantly reduced to 0.67 μm. The main matching surface presented a mirror effect, with roughness of 0.38 μm and 0.46 μm, providing theoretical reference and experimental basis for the finishing of complex curved end faces of 3D printed titanium alloy artificial bones.