Study and Development of Engineering Standard for Press working of Stainless Steel and Copper Components Used in Switchgear

Abstract

Sheet metal forming is the widely used manufacturing process now a day in many company because of its easy and mass production method. In switchgear (circuit breaker) many sheet metal components are used. They are produced by forming operations in mechanical or hydraulic press machine. Due to incorrect forming method or process parameters there are problems like heavy burr, spring-back, wrong dimension and deformation in components which lead to part rejection. Due to them there is waste of time and resources. Cause and effect analysis has been carried out to tackle the problem of resetting and de-latching of MCCB and have been presented in this dissertation work. Three components namely bracket, upper contact and lower contact have been found dimensionally and surface finish wise inaccurate. Which in turn cause the functional problems in MCCB. One additional shaving operation has been suggested to make the bracket dimensionally accurate. Triangular media have been proposed for deburring operation to remove the burrs. Damage to the silver button already brazed to upper contact while ribbing the upper contact has been circumvented by introducing an additional pin locator in the die, burrs in the lower contact have been eliminated by making uniform clearance between punch and die. The modifications helped to reduce rejection of parts and make the MCCB functionally correct.