A DMC (Dynamic Machining Control) model to achieve the optimal control of Material Removal Rate (MRR) for a cutting tool undergoing the considerations of fixed tool life and maximum machining rate is introduced in this research. This study not only applies material removal rate dynamically into the DMC model, but also implements Calculus of Variations to comprehensively optimize the control of material removal rate. In addition, the optimal solution for the dynamic control of material removal rate is also provided. Moreover, the comparison of DMC model and traditional machining model is fully discussed. Furthermore, the decision criteria for selecting the optimal solution of the machining model are presented. This study definitely generates the adaptive concept to dynamically control the material removal rate and provides the efficient tool to concretely optimize the profit of a cutting tool for operations research engineers in today`s manufacturing with profound insight.