The Work Environment of Welding Operators at Volvo Group Trucks Operations : An Investigation to Reduce the Risk of Musculoskeletal Disorders Among Welders

Sammanfattning: This master thesis report presents a 20 weeks long project within Industrial design engineering at Luleå University of Technology, performed at Volvo Group Trucks Operations in Umeå. Since the company from a previous study knew that the operators on segment two work in unfavorable work postures, a further investigation of the operators’ work environment was needed. Therefore, the subject of investigation in this project became the physical workload and more specifically, the factors related to the appearance of work related musculoskeletal disorders (MSDs). Segment two is positioned at the end of Volvos’ production line called finishline where the work is primarily done manual by two shift teams with approximately 14 operators in each one. The project objective was to map the current situation for the manual welding operators at segment two and identify potential ergonomic risks within their everyday work. The focus was placed on finding improvements that could decrease the operators’ risk for developing MSDs during work. The project aim was to develop improvements that direct, and over a longer time span, could ease and improve the operators work situation. By observing, filming, interviewing and hand out questionnaires, the current state for the operators could be mapped. Three interviews were held, 22 questionnaires were answered and almost 50 film sequences were made. The work on segment two are station based where the operators are allocated a specific time for each operation within the station. Usually, the operators rotate after ten truck cabs and then move to the next station. The work consists of screwing, welding, grinding, drilling and controlling. The situation analysis was done by investigating the questionnaire responses further, explore the body postural MSD risks with help of RULA and REBA and using the software AviX to let the operators self-estimate the strain in different muscle groups during work. According to the questionnaires, the operators are highly or partly strained physical and psychological where the experienced psychological strain variates more than the physical strain. Furthermore, most of the operators experienced the occurring work acceleration as positive and the manager and coworker relationship as good. Also, ten operators expressed that they had experienced pain in their body the last 12 months caused by their work and over 70 % of the operators wanted to have a greater opportunity to affect the number of work tasks. By relating this to the findings in the study made at Volvo in 2011, where the investigators identified knee-standing work together with some critical work postures that caused the operators an unfavorable strain in mainly the neck, the back and the arms, I assume that the work on segment two today is performed during similar circumstances and in a similar way. The concept development started with an ideation session together with the operators. Here, the analysis findings were discussed, and my own ideas and improvement suggestions were presented. From these discussions, three tests were arranged including a step construction to facilitate when entering and leaving the truck cab, new knee pads and a stretch program, developed by Volvos’ ergonomist. The findings from the two first tests showed how different the operators found the concepts where some operators appreciated both the step construction and the knee pads, and some didn’t. The stretch test on the other hand, were appreciated by all operators where over 50 % felt an improvement in their body. Also, an educational approach including an additional introduction, updated work instructions and a continuous dialogue about work environmental risks during the group meetings were proposed. The tests resulted in a concept development, a concept evaluation with help of previous established specifications of requirements and the ergonomist, together with an implementation strategy. The strategy proposes an implementation of stretch during the workday within the following months, a further investigation of the knee pads and the step construction, and an implementation of the complete educational approach within 5-10 years. Also, based on the results of this thesis, Volvo are recommended to establish guidelines for how to measure work environmental factors linked to physical and psychosocial work environment. Further, the company are recommended to prioritize their employees’ health, well-being and work environment by working systematically in a close cooperation with the workforce to not risk costs in terms of dissatisfaction, sick leaves and poor reputation.