Improvement of Sewing Machine Design for Assembly Time Reduction Using DFA Methodology

Abstract

The significant element in product development is the reduction of assembly time. Design for manufacturing and assembly (DFMA) plays a vital role in product development where a product uses a variety of components. Design for assembly (DFA) is one of the principles of DFMA. The principal concept of DFA is to maximize the use of existing parts and to eliminate or redesign the components which take more assembly time. Most of the companies use this technique to improve their product design. The aim of the present work is to propose a new design for sewing machine assembly that is better in design efficiency and assembly time.

For this purpose, the Boothroyd and Dewhurst DFA method is used to analyze the above features. The assembly efficiency can be improved by reducing the number of components or redesigning the existing components thereby reducing the assembly time. Simple design with the least number of components makes assembly easy, fast and more economical. A sewing machine is taken as a case study for the purpose of assembly time reduction. It is disassembled and functionality of each component of the machine is studied. It was observed that the total number of components used was 89 and the assembly time of 639.32 sec. In the sewing machine 12 components are eliminated, 2 components and 1 subassembly are redesigned, adhering to its earlier functions. After implementing DFA methodology components are reduced to 77 and assembly time of 392.12 sec.