A novel chip breaker structure of PCD tool for the reaming of 7050 aluminum alloy

The 7050 aluminum alloy is becoming more and more popular in aerospace industry, because it has good wear resistance, high strength, and high toughness while having low density. However, due to the small cutting allowance and good plastic, aluminum alloy chips are usually difficult to be broken naturally in high-speed reaming which induced the machined surface scratched. Both the tool structure and matching process parameters are the key ways to solve this problem. Different sizes of chip breaker have been analyzed by FEM simulation. Based on the FEM, three kinds of PCD reamers which have different chip breakers have been compared with the ability of chip breaking in different cutting parameters. It is found that when rotational speed is 288.8 m/min and feed rate per tooth is 0.04 mm/Z with 0.17 mm depth of chip breaker PCD reamer, the best surface quality and lowest cutting force were achieved. It is also found that the cutting force of shallow-breaker-tool (tool B) is the smallest when compared with non-breaker-tool (tool A) and deep-breaker-tool (tool C). The effect of chip breaker size on cutting force, chip curling, and surface roughness has been analyzed in both dry and wet cutting.