Fatigue Dimensions Among Operators of CNC lathes And Hydraulic Presses: A Comparison of Factor Analyses.
Factor analysis is used to generate groups of variables within scales and questionnaires. Examples of this can be found in numerous fatigue related studies, especially when new instruments to evaluate constructs are developed. Typically, groups of variables have been called dimensions of fatigue. This paper presents the results of the application of the Swedish Occupational Fatigue Inventory Spanish version (SOFI-S) in two groups of industrial workers. The first group engaged in metalworking using CNC lathes, the second group engaged in assembling parts using hydraulic presses. In both cases, CNC lathes and hydraulic presses are classified as Advanced Manufacturing Technology (AMT). The study was conducted at a Constant Velocity (CV) Joints manufacturer located in central Mexico. The SOFI-S questionnaire was administered to a total of 190 operators: 126 CNC lathe operators and 64 CNC hydraulic presses operators. The results show inportant differences in factor extraction between two process analyzed. In machining process, five dimensions of fatigue were obtained. The dimension explaining more variance was constituted by the variables: exhausted, worn out, drained, and warm. While in the assembly process, four dimensions of fatigue were obtained. The dimension explaining more variance was constituted by the variables: yawning, falling asleep, sleepy, indifferent, and listless.