Assessment of cause of difficulty in assembly tasks

Abstract

Assemblability is defined as the ease of assembling parts in a product. It is important to address the factors that affect assemblability, so as to generate knowledge with which to take targeted measures to reduce the difficulty of humans involved in assembly tasks and increase productivity. Existing literature addresses few factors that affect assemblability. Our study focuses on identifying a more comprehensive set of causal factors and a more reliable method for assessing difficulties faced in assembly in terms of these factors. In order to understand these in detail, video recording of a case study of a computer panel assembly is used to identify a set of casual factors that affect assemblability. The researchers analysed the videos using RULA method as a basis for identifying factors potentially responsible for the difficulty. Three causal factors were proposed: reach, visibility, and dexterity. Two subjects independently analysed the videos from the point of view of the hypothesized causes of difficulty based on their perception. The results from subject feedback were correlated with the factors identified and were found to have a high level of correlation. The conclusive statement made from the result is that reach difficulty is primarily indicated by torso movement, vision difficulty by head movement, and dexterity difficulty by hand movement.