B. Moetakef Imani - Assistant professor, Department of Mechanical Engineering,Ferdowsi University of Mashhad, Mashhad, Iran
M.H. Sadeghi - Assistant professor, Department of Mechanical Engineering, Tabriat Modares University Tehran, Iran
M. Kazemi Nasrabadiq - Department of Aerospace Engineering, shahid Sattari Air University Tehran, Iran,

The stability behavior of loww immersion helical end milling processes is investigated in this paper. Low radial immersion milling operations involve interupted cutting which induces chatter vibration under certain cutting conditions. Time Finite Element Analysis (TFEA) is suggester for an approximate solutian for delayed differential equations encountered during interrupted milling . An improved TFEA is proposed which includes the effects of helix angle variations on cutting force, cutting time and specific cutting force coefficients. For this purpose , five different cases were distinguished for engagement limits of the cutting edges. It has been observed that an increase in the hlix angle improves the stability limit of theprocess . This is related to the flip bifurcation lobes start to separate from the main lobes and shape isolated unstable islands. By further increasing the helix angle, unstable islands will vanish.

Low Immersion Milling , Stability, To,e Finite Element Analysis, Helix Anlge