TO Causes of Failure in Vertical Roller Mill Gearbox GRINDING EUIPMNET ANALYSIS

Abstract

The aim of this study to investigate the Failure Mode and Effect Analysis (FMEA) of Vertical Roller Mill (VRM) gearbox at power cement limited Nooriabad Sindh Pakistan. Risk Priority Number (RPN) is the indicator for determining proper corrective action on the failure modes. It is calculated by multiplying the severity, occurrence and detection ranking levels resulting in a scale from 1 to 1000. By comparing the RPN values of components with RPN equal to or more than 40 had been considered critical components. The value of RPN is high in case of design error of gearbox as result of high RPN. So the design error of gear box given first priority to be minimized. In case of Raw Material input machine the value of RPN is estimated high but less design error. Quality of raw material that is fed to the machine that is be good and that be fed as per requirement. Mechanical Overload also responsible for failure of sub components the value of RPN is higher due other causes of failure than the value of design error. RPN for bevel pinion shaft and bevel wheel before and after implementation of corrective action indicates that failure of any one of them result in failure/replacement of other. The other causes of failure of gearbox of VRM are design error, mechanical overload, presence of debris / contamination, connection failure, insufficient input from site, raw material quality heat treatment, manufacturing or assembly error and insufficient lubrication.