Classification and Quantification of Human Error in Manufacturing: A Case Study in Complex Manual Assembly

Yaniel Torres,Kurt Landau,Sylvie Nadeau

doi:10.3390/app11020749

Abstract

Manual assembly operations are sensitive to human errors that can diminish the quality of final products. The paper shows an application of human reliability analysis in a realistic manufacturing context to identify where and why manual assembly errors occur. The techniques SHERPA and HEART were used to perform the analysis of human reliability. Three critical tasks were selected for analysis based on quality records: (1) installation of three types of brackets using fasteners, (2) fixation of a data cable to the assembly structure using cushioned loop clamps and (3) installation of cap covers to protect inlets. The identified error modes with SHERPA were: 36 action errors, nine selection errors, eight information retrieval errors and six checking errors. According to HEART, the highest human error probabilities were associated with assembly parts sensitive to geometry-related errors (brackets and cushioned loop clamps). The study showed that perceptually engaging assembly instructions seem to offer the highest potential for error reduction and performance improvement. Other identified areas of action were the improvement of the inspection process and workers’ provision with better tracking and better feedback. Implementation of assembly guidance systems could potentially benefit worker’s performance and decrease assembly errors.

Highlights

An efficient and reliable assembly process is a critical aspect of manufacturing, ensuring that the final product meets the required quality level
Numerous manual assembly tasks are performed on the assembly line, but for the Numerous manual taskspresented are performed the assembly but for selected the purpose ofassembly the case study in thison paper, three basicline, tasks were as critical purpose of thetasks
simulator for human error probability analysis (SHERPA) analysis shows that brackets and cushioned loop clamps are sensitive to operation in the wrong direction (A3) and to misalignment (A5)

Summary

Introduction

An efficient and reliable assembly process is a critical aspect of manufacturing, ensuring that the final product meets the required quality level. Engineers usually consider several variables when selecting an appropriate assembly system. In manufacturing domains where product complexity and variety present particular challenges, manual work remains a viable alternative. This is the case of such manufacturing domains as consumer electronics [3], aerospace manufacturing [4,5], combustion engine assembly [6], automotive manufacturing [7,8] and the production of industrial machines and tools [9,10]. For manual assembly to yield a final product of the appropriate level of quality, several operations must be executed properly. A different fastener installed, e.g., shorter bolt same caliber.

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Conclusion