Feedrate Optimization for Pocket Machining Considering Cutting Force Constraints

Pocket machining is widely used to manufacture complex structure parts in the aerospace and automotive industries. Improving productivity remains one of the core concerns for pocket machining. However, the higher feedrate also means the larger maximum cutting force during machining, which would decrease tool life and even cause tool rupture. Therefore, limiting the maximum cutting force during pocket machining is of significant importance. This paper develops the linear-programming (LP) based feedrate optimization algorithm with a novel cutting force limitation strategy. The optimized feedrates are obtained under both kinematic and cutting force constraints. First, the cubic B-spline spiral path is constructed. Then based on geometric features of the B-spline spiral toolpath for pocket machining, the cutting force is evaluated by proposing the equivalent feed per tooth and modified cutter engagement. Utilizing the linear relationship between feedrate and cutting forces in axis directions, the cutting force constraints are equivalently converted to the maximum allowable feedrate. Finally, the cutting force constraints and the kinematic constraints are integrated to formulate the LP model for feedrate optimization. The experimental results indicate that the enhanced feedrate optimization approach enables significant improvement in machining efficiency while keeping the maximum cutting forces at the same level.