Milling Cutting Force Model Including Tool Runout

Tool radial runout is an inevitable phenomenon which significantly affects the cutting conditions in a milling operation. Indeed, tool runout causes irregular spacing between cutter teeth creating uneven engagement conditions. This aspect may limit the accuracy and reliability of the predictive approaches dealing with important phenomena in milling such as chatter, surface errors and tool wear. For these predictions, a cutting force model, which includes tool runout, is essential, but it requires complex formulations which limit its application. This paper presents a simplified cutting force model for an endmill with generic geometry then adapts it to represent the effect of radial runout on a regular endmill. The model thus obtained expresses the cutting forces as a Fourier series considering the effect of tool runout on the cutting force frequency components, and it is easy to apply to other predictive models. The proposed formulations are validated, and an application is presented.