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Mongkhon Chinnakort; Nitidetch Koohathongsumrit

Authors

Mongkhon Chinnakort Engineering Management and Technology, Faculty of Engineering, Ramkhamhaeng University, Bangkok 10240
Nitidetch Koohathongsumrit Department of Statistics, Faculty of Science, Ramkhamhaeng University, 2086, Ramkhamhaeng Road, Huamak, Bangkapi, Bangkok, 10240, Thailand https://orcid.org/0000-0002-0174-4760

Keywords:

Factorial design of experiments, Seat-slide rail, Reduction of nonconforming product, Production process improvement

Abstract

This purpose of this study is to reduce the number of four-way electric motor-adjustable automotive seat-slide rails with an average bearing stopper hole depth below 1.40 millimeters. The problem arises from the parameter settings of bearing stopper hole drilling machine. The related parameters are drilling depth, air pressure, and steel-plate thickness. To address the problem, this study employed the factorial design of experiments to identify the optimal conditions for the drilling process. The results indicated that the appropriate parameter settings consist of drilling depth of 3 millimeters, air pressure of 160 bar, and a steel-plate thickness of 5 millimeters. After implementation of these parameter settings in the actual production process, the average bearing stopper hole depth of the automotive seat-slide rails reached 1.80 millimeters, which is statistically significantly higher than the specification of 1.40 millimeters. In addition, the case study achieved 48% reduction in the number of four-way electric motor-adjustable seat-slide rails with bearing stopper hole depths below the specification when compared with the defect rate before process improvement. The benefits of this study enhance product quality and improves production process consistency for supporting sustainable manufacturing performance in the automotive industry.

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