The Effect of Tool Flexibility on Back-Cutting in End Milled Surfaces

Abstract

End milled surface texture is inhomogeneous and often exhibits complex lay patterns. An important contributing factor to these surface characteristics is the back-cutting effect. This effect causes cutter tooth mark patterns on the surface in the forward and reverse tool feed directions. In this paper, the dependence of back-cutting on end mill flexibility and its influence on the slot floor surface texture are modeled and experimentally verified. It is shown that the extent to which tool flexibility affects back-cutting is determined by the resultant cutting force system and not the feed force alone. The variation in the amount of back-cutting typically observed across the width of a milled slot is also explained by this model. The model, although simple in form, yields reasonably good agreement with the measured surface profiles.