Effects of two ergonomic improvements in brazing coils of air-handler units

An ergonomic evaluation of workers in the winding section of the pump manufacturing industry

BACKGROUND: Work-related musculoskeletal disorders (WMSDs) are prevalent and have an impact across occupations. However, there are very few studies that document the prevalence of WMSDs in the pump industry. In manufacturing industries, the common issue for WMSDs and physiological stress among the workers is caused by poor working posture. OBJECTIVE: To investigate the occupational risks at the winding station in the pump manufacturing industry. In addition, this study examined the influence of work-study on mitigating occupational risks. METHODS: Workers who were involved in circular coil winding and insulation testing were considered for the study. Awkward postures adopted while performing these tasks cause fatigue, injuries and WMSDs. Tasks were evaluated as per the National Institute for Occupational Safety and Health (NIOSH) standards. A work-study was conducted to better understand the workflow. Virtual ergonomic postural evaluation (Rapid Upper Limb Assessment, RULA) was used to identify the occupational risks. RESULTS: Time taken for making circular windings and insulation testing (7.5 Hp submersible motor) was found to be 4.04 minutes and 0.95 minutes, respectively. A CAD model was used for ergonomic evaluation in the virtual environment. The RULA final score of 2 and 3 is attributed to coil winding and insulation testing. CONCLUSION: For further studies, the whole pump manufacturing process should be taken into account. The ergonomic tools used in this study will considerably reduce the occupation risks at the winding station in the pump manufacturing industry.

Virtual postural assessment of an assembly work in a small scale submersible pump manufacturing industry

BACKGROUND

Depletion of groundwater has increased the depth of bore wells drilled to meet water requirements. Water from these bore wells are accessed by operating submersible pumps with multi-stages. The number of stages of submersible pump directly depends upon the depth of bore well. Health-related risk such as Musculoskeletal Disorders (MSDs) arises during the manual assembly of these pumps in an awkward posture.

OBJECTIVE

The objective of this paper is to eliminate or reduce risk in the manual assembly of submersible pumps using virtual postural analysis. Secondary objective is to redesign the existing workstation incorporating ergonomic interventions.

METHODS

It reports a case study in which postural analysis is carried out with the help of Rapid Upper Limb Assessment (RULA) method.

RESULTS

It is observed that inserting the stage casing weighing around 1.5 Kg through top end of the shaft is the awkward working posture involving a flexion of the arm about 152°. RULA score (7) indicate a high level of risk exists in the workstation, calling for investigate and change the working posture immediately. In order to reduce this risk, a redesigned workstation has been proposed.

CONCLUSION

This study results help in minimizing the awkward postures, thereby reducing the health-related risk. This will also increase the efficiency of the worker and his productivity.

Impact of task design on task performance and injury risk: case study of a simulated drilling task

Existing evidence is limited regarding the influence of task design on performance and ergonomic risk, or the association between these two outcomes. In a controlled experiment, we constructed a mock fuselage to simulate a drilling task common in aircraft manufacturing, and examined the effect of three levels of workstation adjustability on performance as measured by productivity (e.g. fuselage completion time) and quality (e.g. fuselage defective holes), and ergonomic risk as quantified using two common methods (rapid upper limb assessment and the strain index). The primary finding was that both productivity and quality significantly improved with increased adjustability, yet this occurred only when that adjustability succeeded in reducing ergonomic risk. Supporting the inverse association between ergonomic risk and performance, the condition with highest adjustability created the lowest ergonomic risk and the best performance while there was not a substantial difference in ergonomic risk between the other two conditions, in which performance was also comparable. Practitioner Summary: Findings of this study supported a causal relationship between task design and both ergonomic risk and performance, and that ergonomic risk and performance are inversely associated. While future work is needed under more realistic conditions and a broader population, these results may be useful for task (re)design and to help cost-justify some ergonomic interventions.