International Journal Of Advancement In Engineering Technology, Management and Applied Science (IJAETMAS) ISSN: 2349-3224 || www.ijaetmas.com || Volume 03 - Issue 07 || July 2016 || PP. 83-90 www.ijaetmas.com Page 83 DFMEA of a Roller Mill Gear box Shaik Himam Saheb 1 Vijay Kumar Annam 2 Yogesh Avula 3 123 Department of Mechanical Engineering,GNIT,Hyderabad Authors E-mail: himam.mech@gmail.com ABSTRACT: Design FMEA is structured method of identifying potential failure modes and providing corrective actions before first production run occurs. This paper aims to provide probable causes of failure, levels of effects of failure and corrective actions to be taken in the design phase for Bevel-Planetary Vertical Roller Mill Gearbox. Keywords—DFMEA, Bevel-Planetary Gearbox, Vertical Roller Mill, Risk Priority Number I. INTRODUCTION 1) Vertical Roller Mills: Vertical roller mills (VRM) are well accepted as most effectual means for grinding raw material in cement and power generation industry. These mills are driven by heavy duty gearboxes with horizontal input shaft and vertical output shaft [i]. Generally, Bevel-Helical or Bevel-Planetary gearboxes are used for VRM. The gearbox is integral component of VRM as its output flange is rigidly connected with the mill grinding table. Fig. 1 shows the general arrangement of VRM with gearbox located at its bottom. Fig. 1: VRM with Bevel-Helical Gearbox (Left) and Bevel-Planetary Gearbox (Right) The output torque which is the foremost design criteria for the gearbox, has to be increased with increasing capacity of the mills [i]. This has put limitations on using Bevel-Helical gearboxes. Additionally, Bevel-Planetary gearboxes stand out with the following advantages over Bevel-Helical making them preferred choice for the application:  Impervious to vertical impacts (grinding force) since the gears are isolated from the table or lower grinding bowl of the mill.  Rigid because of round housing form.  Precision machined because of the circular form.  Easy to both assemble and disassemble because of the ease with which the thrust plates and the gears can be removed and due to the absence of gaskets necessary for sealing a split gear housing.  Compact because the forces are being distributed in planetary stage.  Quiet running because the high speed bevel stage being located deep within the gear unit.  Efficient because of the loss –free coupling performance of planetary gear.