An ergonomic approach to evaluation of compelling postures in the assembly line balancing problem

Assembly line balancing problems aim to assign all required tasks efficiently and effectively to workstations in a flow-oriented production system. However, due to repetitive work and static postures on assembly lines, it causes Musculoskeletal Disorders in employees. In this thesis, it is aimed to address an assembly line problem that not only aims to reduce the number of stations but also balances the ergonomic strain. Time study and operation times and ergonomic risk values per station were determined by the REBA (Rapid Entire Body Assessment) method for the workers in the stations. In the engine assembly line of a heavy commercial vehicle enterprise, the cycle time is 14.31 minutes and the total balancing delay is 42.64 minutes for 198 workers at 24 stations. In this line, REBA scores range from 6 to 55. With the GAMS package program, the assignments were made with the optimum solution of the assembly line balancing problem, the number of stations was 23 and the total balancing delay was 28.33 minutes in the analysis. In the solution containing ergonomic risk constraint, the number of stations increased to 29, while the total balancing delay was calculated as 114.39 minutes. However, the distribution of REBA scores per station varied between 6 and 30. In the model; Sensitivity analysis was carried out by solving it with different tolerance margins for the current average ergonomic risk constraint, with the model containing the weighted ergonomic risk constraint, and with new targets created in line with the variable production demand.