| WANG Kun,LYU Yifan,LI Fangqi,WANG Weicheng,ZHANG Jifeng,ZHU Weiguang.Numerical Simulation and Experimental Study of Abrasive Flow Machining of 3D Printed Knee Joint Surfaces[J],53(22):149-160 |
| Numerical Simulation and Experimental Study of Abrasive Flow Machining of 3D Printed Knee Joint Surfaces |
| Received:February 19, 2024 Revised:July 29, 2024 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.22.013 |
| KeyWord:abrasive flow machining 3D printing titanium alloy knee joint imitation fixture precision machining |
| Author | Institution |
| WANG Kun |
College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot , China |
| LYU Yifan |
College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot , China;Falcon Tech Co., Ltd., Jiangsu Wuxi , China |
| LI Fangqi |
College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot , China |
| WANG Weicheng |
Falcon Tech Co., Ltd., Jiangsu Wuxi , China |
| ZHANG Jifeng |
Falcon Tech Co., Ltd., Jiangsu Wuxi , China |
| ZHU Weiguang |
College of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot , China |
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| Abstract: |
| 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. |
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