A Methodology for Detecting Musculoskeletal Disorders in Industrial Workplaces Using a Mapping Representation of Risk

A correct identification of ergonomic risks and their physical location in production areas becomes vital for the prevention of work-related illnesses. The method proposed for detecting musculoskeletal disorders (MSDs) in industrial workplaces has the objective of identifying the relationship between the workplace design and the nonergonomic task content. A mapping of work conditions was implemented to develop a diagnosis about hazards and ergonomic risk factors present in the work system. The information collected was organized in an ergonomic risk map with the following structure: inputs, information about risks and hazards, process, information about how the risk exposure leads to MSDs and outputs, and information about the consequences of risk factor exposure. The mapping results allowed determining the causes of work-related illnesses in activities of polishing and screening metals, establishing as a main cause of risk the barrel height (1.70 m) that forces the material handling above the shoulders. Force demands required to perform the task (around 277 N in each lifting) were determined. The work-related illnesses identified were low back injuries and rotator cuff injures. The information contained in the map improves the understanding of employers and workers about the origin of ergonomic problems and supports the decision-making about improvement projects focused on risk elimination

How Poor Workstation Design Causes Musculoskeletal Disorders: Research from QOC Matrix the Workers’ Voice

An ergonomic intervention method based on QOC Matrix the workers’ voice was implemented in a study case. The diagnosis and analysis developed are used in improvement proposals for workstation redesign. The workers’ voice resulting from reports of the employee’ complaints and symptomatology was the base for a standardized method that comprises: (a) QOC questionnaire application, (b) risk factor categorization, (c) determination of unsafe and unhealthy ergonomic metrics, (d) figuring out the task content impact in the workers’ body, and (e) work system diagnosis. Since workers’ voice, the risk identification made included: (1) the task content linked to work method: repetitiveness associated with the sensor activation using the fingers and the repetitive movements include twist and the stretch of wrist, (2) workplace design regarding container height and injuries caused in wrists and elbows due to hits, (3) task developed regarding risk time exposition and workers position, and (4) workplace design regards to housing collector distance from filling area linked to workers position adopted for reach bags. Improvements included redesign of the workstation with a system of 90° exit discharge curve, one elevation system, and a photoelectric sensor in filling nozzle for automatic filling. As an improvement result, the activity called bags provision was eliminated from the task

Design and Programming of a Wire Winder Device for Extrusion Activity in the Metal-Mechanical Industry

The present research is focused on the analysis of an industrial activity where the case under study is wire extrusion activity, which has been developed using old machines. This activity is analyzed considering the task and its elements to identify the movements and sequence of actions performed by the workforce and the machines. One of these activities is the roll-up of lead wire coming from the extruding machine. The task is done by the workforce 73 times during a shift and roughly consists in transporting the wire to the pulley guide and driving the lead wire until the container is rolled up manually. The analysis shows that the workers are exposed to hazardous conditions that could affect their health, meaning they are under risk of suffering an injury or a disease by exposure to repetitive actions and high temperatures (>90°C). Based on the latter, the design and development of a wire winder device has been proposed, which implements a programmable logic controller and servomechanism to replace the activities done manually. A ladder diagram is proposed to control the action performed by the servomechanism based on a stimulus received from the environment

Design of a Fuzzy Logic Evaluation to Determine the Ergonomic Risk Level of Manual Material Handling Tasks

In this work, we propose a fuzzy inference as a decision support system built in the MATLAB Fuzzy Logic Designer for evaluating manual material handling risk conditions. The input variables for the fuzzy decision were: (1) the total time duration of the manual material handling in one shift of 450 min, with 3 h considered the maximal exposition time; (2) 25 kg as a maximal mass reference which should never be exceeded; (3) the repetitiveness of the manual material handling task through the shift considering as the maximal frequency of four lifts per min. Results of 135 earlier direct ergonomic evaluations made using the method proposed by the ISO 11228-1 were used as validator results, and called “expected results”. The experimentation intended to simulate an ergonomic evaluation in different boundary conditions of work and verify if the fuzzy interface could correctly replicate the results of the ergonomic evaluations. As validation, the list with the 135 expected results was compared against the evaluation made by the fuzzy logic interface, called “Work_Conditions”. From the comparison, only three evaluations (0.02%) differed with respect to the expected results. Consequently, it is concluded that the fuzzy interface can be used as a tool for automating the determination of manual material handling ergonomic risk levels, with great precision