Comparing up and Down Milling Modes of End-Milling Using Temporal Finite Element Analysis

Two types of end milling at partial radial immersion are distinguished in this work, namely; up and down end-milling. They are theoretically given comparative study for a three tooth end miller operating at 0.5, 0.75 and 0.8 radial immersions. 0.5 and 0.8 radial immersion conditions are chosen so that analysis covers situations in which repeat and continuous tool engagements occur while 0.75 radial immersion just precludes tool free flight. It results from analysis that the down end-milling mode is better favoured for workshop application than the up end-milling mode from both standpoints of cutting force and chatter stability. This superiority in chatter stability is quantified by making use of the Simpson’s rule to establish that switching from up end-milling mode to down end-milling mode at 0.5 radial immersion almost doubles the possibility of chatter free milling while at 0.75 and 0.8 radial immersions this possibility almost triples. This result conforms to the age long recognition from workshop practices that climb milling operations are much more stable than conventional milling operations. Validation of the resulting stability charts is conducted via MATLAB dde23 time domain numerical analysis of selected points on the parameter plane of spindle speed and depth of cut.