Ergonomic redesign of sewing workstation for garments manufacturing: a case study of Rivatex East Africa Limited, Eldoret, Kenya

Abstract

Worldwide, the design of a workstation in many garment industries is usually done with minimal consideration of anthropometric data. This may cause hazards and reduce work efficiency as a result of sitting for long periods of time in uncomfortable positions. Ergonomically redesigned workstations are known to reduce Musculoskeletal Disorders (MSDs) and improve the motivation of the garment workers in the workstation environment. The main objective of this study was to redesign an ergonomic sewing workstations for garment manufacturing using selected anthropometric data collected at Rivatex East Africa Limited (REAL), Eldoret, Kenya. The specific objectives were: to assess work-related risks and hazards for garments making workers at sewing workstations; to determine the relevant anthropometric dimensions from garments-making workers for a sewing workstation; to redesign a sewing workstation for garments-making workers; to simulate the redesigned sewing workstation; to optimize the redesigned workstation for garments-making workers at sewing operations; and to fabricate the redesigned sewing workstation. Rapid Entire Body Analysis (REBA) method was used to assess the ergonomic risk of the existing workstation. The sample size of 100 was determined. Eleven anthropometric measurements were taken from workers using ISO 7250-1:2017 and compared using one-way analysis of variance (ANOVA). Using the anthropometric data, a redesigned sewing workstation model was proposed. The model was analyzed using Computer Aided Three-Dimensional Interactive Application (CATIA V5) software based on Rapid Upper Limb Analysis (RULA). The model was simulated using SolidWorks 2024 software based on Finite Element Analysis (FEA). Aluminum alloy 1060 was selected for FEA. The FEA criteria included: stress, displacement, strain and Factor of Safety (FOS). The model was optimised using design study. The model was then fabricated in accordance with the necessary manufacturing process. ANOVA tests results failed to reject the null hypothesis in the data sets (P > 0.05), thus, there was no significant difference between the anthropometric data. The recommended dimensions for workstations are redesigned, significantly reducing the mismatches between workstation dimensions to the relevant body dimensions. Analysis results of the workers' posture for the existing sewing workstation had a final REBA score of 5, implying existence of medium ergonomic risk, hence, changes were necessary. The proposed sewing workstation had a final RULA score of 1, meaning that the ergonomic risk is negligible. The FEA results showed that the maximum stress was 7.175E-01 MPa and did not exceed the yield strength; the maximum deformation was 0.03209 mm, which was below the assigned safety level; the maximum strain was 6.258E-06 and within the range for the material; and the minimum FOS distribution was 3 implying that the model was within the safety range limits. The optimisation results showed that the optimal dimension of the model was 416.5 mm for seat height, 457 mm for seat depth and 472.8 mm for seat width; the optimal stress of the model was 2.662E+01 MPa; and the optimal mass of the model was 19865.24 g. In conclusion, the dimensions of the redesigned sewing workstation was recommended. The proposed redesigned workstation should be suitable for all garment workers in Kenya.