A new method for determining the undeformed chip thickness in milling

The determination of the instantaneous undeformed chip thickness is one of the key issues in the modelling of milling processes. The traditional chip thickness model, with an approximation form of h=ft sin θ, assumes the tooth path to be circular, and thus lacks accuracy. In this paper, a new approach for determining the undeformed chip thickness in milling with much higher accuracy is proposed. Through analysis of the true tooth trajectories, the true instantaneous undeformed chip thickness can be calculated by solving the deduced transcendental equation. Rather than using the cumbersome numerical method, a Taylor’s series is used to approximate the involved infinitesimal value in the transcendental equation, which results in an explicit expression for practical determination of the undeformed chip thickness with higher accuracy compared to the traditional model.