The Movable Cellular Automata (MCA) method is introduced into the analysis of cutting process, and is employed to build the discretised MCA tool-chip model of orthogonal cutting. The chip breaking and curling rule are proposed to determine the MCA local rule. The simple local rule and discretised method are presented to describe the continuous process of chip’s formation and breaking. The states’ rule of a cell and its neighbors can be used to predict and calculate the chips’ breaking and curling. The numerical calculation and a numerical example in the process of chip breaking and curling are proposed.