Influence of Container Size on Processing Effect of Vertical Forced Vibration Finishing for Blades

A compressor blade is a key component of an aero-engine often in a high-speed, high-temperature, and high-pressure environment. After milling, there are surface defects such as milling cutter marks and microcracks on the surface of the blade. The
surface quality after milling cannot meet quality requirements, therefore the final working surface must undergo surface finishing. In this paper, the surface finishing of the blade is realized by the vertical forced vibration finishing process. At present, research on the relationship between excitation parameters and the behavior of granular media is relatively advanced, yet few scholars have studied the influence of container size on the behavior of granular media. In order to explore the influence of container size on the finishing effect of compressor blades, the dimensions of the regular prismatic container were taken as variables, and based on the discrete
element method, the change in the mechanical behavior of granular media on blades and the change in the processing effect for different container size parameters were analyzed. Subsequently, optimum container size parameters were determined. The effectiveness of the simulation was verified via contact force test analysis and processing tests. Results show that when the installation position of the blade is relatively unchanged, during the vibration process, the mechanical behavior of the granular media on the blade is affected by the size of the container, which in turn affects the processing effect of the blade. The height of the container has the most obvious influence on the processing effect of the blade. As the height of the container increases, the contact force on the blade surface increases, the relative velocity between the blade surface and the granular media increases, the processing efficiency increases, and thus processing is more uniform. The container width has the second greatest effect on the machining effect of the blade. As the width of the container increases, the contact force on the blade surface gradually decreases, the relative velocity between the blade surface and the granular media initially increases before decreasing, the processing efficiency initially increases before decreasing, and the uniformity gradually deteriorates. The length of the container has the least influence on the processing effect. As the length of the container increases, the contact force on the blade surface gradually decreases, the relative velocity between the blade surface and the granular media initially increases before decreasing, the processing efficiency decreases, and the uniformity deteriorates. After a comparative analysis, the optimum container size parameters were determined; when the height of the container was 300 mm, the width was 120 mm, and the length was 200 mm, the processing effect was optimal. After the optimum container size parameters were
used to process the specimen, the surface roughness was reduced from 0.645 mu m to 0.246 mu m, reaching the surface roughness industrial requirements for an aero-engine blade. The surface profile was relatively flat, and the milling marks were removed.
Moreover, a preliminary understanding of the influence of container size on the motion behavior of granular media under vertical vibration was obtained, providing a theoretical basis for the optimization of container size in barrel finishing processing