An enhanced model for the dynamic behavior of the end milling process is described. The model predicts the cutting forces and cutter deflections by including the effects of the flank face interference mechanism in addition to the chip removal effects. The interference mechanism is accounted for by considering the flank interference forces to be proportional to the interference volume. The volume of interference is estimated numerically. The total force acting on the tool is a combination of the forces due to the cutting action and forces due to the interference. Experiments performed on 6061-T6 Aluminum validate the simulation results.