Engineering polymers in automobile seat belt lock applications: it’s development, investigation and performance analysis

Abstract

Almost all vehicles use seat belts for occupant’s safety. The seat belt locking system consists of buckle assembly where the tongue plate enters the buckle assembly and locks automatically. The tongue plate is made by over molding injection process to a metal plate, which requires two distinct & different process techniques to produce. In this research, the tongue plate is completely redesigned into a single piece injection molded part replacing the sheet metal part. The parts are produced using ‘Delrin’ and ‘Nylon 6-GF 30%’ material separately by injection molding machine strictly following the International standard. Then, pertinent data were collected from mold flow analysis. The injection molding process is used to produce the component as a single part, which eliminates the sheet metal process, hence eliminating sheet metal die, process, post finishing operations, inventory etc. that reduces production cost, time and multiple numbers of parts. The tongue plate which is made by sheet metal and then polymer is being over molded into it, increases the process cost and also the chance of QC failure. This research concludes that the tongue plate may be produced as a single injection molded part with high accuracy, finish, strength and at a lower cost.