Parametric Study and Optimization in Deep Drawing of Headlight Reflector

Abstract

Major surface defects which occur in the deep drawing process are wrinkle formation and tearing. In the headlight reflectors of vehicles, it is not accepted because any deviation in the profile of the reflector can impact its performance. Since defective parts need to be either reject or rework, a lot of money and time is wasted in the production process. Hence, it becomes essential to avoid the production of defective parts. Luman Auto Light Private Ltd. was having an issue during the development of the reflector of the headlight of the TATA 407 vehicle. It was witnessed that some portion of the reflector is having wrinkles while some is having tearing of the sheet; it was, therefore, important to establish possible causes of wrinkles and cracks to reduce the losses. In the adopted procedure, three basic steps have been taken to determine the various causes of wrinkles and cracks. Various reasons responsible for wrinkling formation are studied in the first step. Comprehensive study of process was done and actual working conditions were also observed in the company. Taguchi’s approach was adopted in the designing of experiments in the second step. L16 orthogonal array was used and three variables were varied at four levels. Punch speed, coefficient of friction and blank holder force were selected as three parameters. The experiments were simulated in Simufact software and they provided the result in the form of thickness distribution. The optimized level of each variable was selected based on the signal-to-noise ratio. Further, the quality of the drawn product is assessed on the basis of the contribution of individual variables.