Design of chip breaker and study on cutting performance in reaming 7050 aluminum alloy

摘要

Chip breaker is considered to be one of the most effective methods in chip control, which has been widely used in metal machining. Reaming is the final finishing operation in hole machining; smaller geometrical tolerance and higher surface quality should be achieved in reaming process. According to the characteristic of reaming operation, a smaller cutting allowance was required, thus inducing thin chips generated and hard to be broken, especially machining highly ductile materials, such as the 7050 aluminum alloy. In this study, the design of chip breakers on cutting edge of polycrystalline diamond (PCD) reamers was analyzed. Based on the characteristics of reamer and chip breaking conditions, theoretically chip breakage ranges for depth of chip breaker were deduced. According to theoretical ranges, two chip breaker reamers, with depths of 0.2mm and 0.4mm and a width of 0.5 mm, were designed and compared based on the chip breakability with a conventional non-chip breaker tool. The finite element method (FEM) analysis and reaming experiments were used to verify theoretical deduction. The results showed that chip breaking performances by FEM simulation and experimental research are in good agreement with predictions. Chip breakability of tool B (within theoretical range) has improved compared with the other tools. This study also provides a reference for the fabrication of chip breaker on reamers to improve chip breakability and surface quality.