Time Reduction in the "Weld-Assembly" Process for Various Types and Low Volume of Products

Abstract

This paper deals with reduction of manufacturing time for various types and low volume of products in the process of arc-welding assembly.
As an example of "weld-assembly" process, we examined the case of assembling dump-bodies where 23 kinds of bodies are assembled through 26 stages of weld-assembly jigs. The jigs are instantaneously moved to a new configuration by servo motors or pneumatic cylinders, eliminating waiting time to change the arrangement for new products.
In order to minimize a total weld-assembly time, a simulation-method was developed for determining the most suitable sequence of works. A result of simulation shows that a difference of total time between the most suitable and the worst cases is as great as 9%. To maintain a good process efficiency with the help of the simulation, data-aquisition system was established to get the weld-assembly time for each work at each stage, and the weld-assembly line was designed to centrally computer-controlled.
At the early stage of the development simulation time was too long to use the method practically, therefor we examined the way of reducing simulation-time by the characteristics of specific combination of work-sequences and so on.