Saf Health Work.  2012 Jun;3(2):146-153.

Discomfort Analysis in Computerized Numeric Control Machine Operations

• Muthukumar K
• Sankaranarayanasamy K
• Ganguli AK

Abstract

OBJECTIVES
The introduction of computerized numeric control (CNC) technology in manufacturing industries has revolutionized the production process, but there are some health and safety problems associated with these machines. The present study aimed to investigate the extent of postural discomfort in CNC machine operators, and the relationship of this discomfort to the display and control panel height, with a view to validate the anthropometric recommendation for the location of the display and control panel in CNC machines.
METHODS
The postural discomforts associated with CNC machines were studied in 122 male operators using Corlett and Bishop's body part discomfort mapping, subject information, and discomfort level at various time intervals from starting to end of a shift. This information was collected using a questionnaire. Statistical analysis was carried out using ANOVA.
RESULTS
Neck discomfort due to the positioning of the machine displays, and shoulder and arm discomfort due to the positioning of controls were identified as common health issues in the operators of these machines. The study revealed that 45.9% of machine operators reported discomfort in the lower back, 41.8% in the neck, 22.1% in the upper-back, 53.3% in the shoulder and arm, and 21.3% of the operators reported discomfort in the leg.
CONCLUSION
Discomfort increased with the progress of the day and was highest at the end of a shift; subject age had no effect on patient tendency to experience discomfort levels.

Keyword

Discomfort; Computerized numeric control machines; Anthropometry; Human engineering; Work-related musculoskeletal disorders; Discomfort mapping

MeSH Terms

Anthropometry
Arm
Human Engineering
Humans
Male
Neck
Surveys and Questionnaires
Shoulder