Design and Development of an Ergonomic Milling Machine Control Knob using TRIZ Principles

TRIZ, a Russian abbreviation known as the Theory of Inventive Problem Solving, refers to a methodology for problem-solving rooted in logic and data rather than intuition. It promotes the ability to solve problems creatively. Using TRIZ tools for problem-solving such as the cause-effect-chain analysis and engineering contradiction, a new ergonomic milling machine control knob was developed for improved musculoskeletal comfort. The major improvisations from the original milling machine knob included its spherical shape design, the indentations to accommodate a lateral pinch and the addition of a rubbery material for increased sensation. In the validation test, it was found that this new and improved ergonomic milling machine control knob was able to reduce the amount of pinch force by about 72% for males and 55% for females compared to the original knob, hence potentially eliminating risks of overexertion in pinch grips. This solution potentially reduces occupational injuries and cumulative trauma disorders. An implicit benefit is that the quality of machined parts using the milling machine can be potentially enhanced due to better control of the machine knobs that could eventually lead to the reduction of rejects and reworks, which also translates to improved productivity.