Human factors in visual quality control

Visual control (visual inspection) is often used in production because - in comparison to other kinds of control - it is relatively easy to conduct. It does not require any specialized technical equipment. Human senses, usually sight, are the measurement tool. Unfortunately, visual control does not guarantee a fully correct assessment. The reason is the limited human reliability. There are plenty of factors which influence ability of a human to assess the process or product quality properly. An important group of them are ergonomic factors. The goal of the paper is to identify and discuss their influence on the efficiency of the visual quality control in manufacturing processes. The research was carried out in manufacturing company from automotive industry. The paper presents the investigation of work organizational factors influence on visual control effectiveness. A controller can make two types of errors in the process of visual inspection: to assess a conforming product as “defective” or to assess a non-conforming product as “good”. Effectiveness of sequential visual controls in selected process was examined. As a measure of visual control effectiveness Control First Pass Yield index was defended. Three operations were analyzed: assembly of components, melting components and applying a protective coating.