Title: Continuous improvement of injection moulding using Six Sigma: case study

Authors: Ahmed Maged; Salah Haridy; Saleh Kaytbay; Nadia Bhuiyan

Addresses: Mechanical Engineering Department, Benha Faculty of Engineering, Benha University, Egypt ' Department of Industrial Engineering and Engineering Management, College of Engineering, University of Sharjah, Sharjah 27272, UAE; Sustainable Engineering Asset Management (SEAM) Research Group, University of Sharjah, UAE; Benha Faculty of Engineering, Benha University, Benha 13512, Egypt ' Mechanical Engineering Department, Benha Faculty of Engineering, Benha University, Egypt; Higher Institute of Engineering and Technology, Mahalla Al – Kubra, Egypt ' Concordia Institute of Aerospace Design and Innovation, Faculty of Engineering and Computer Science, Concordia University, Canada

Abstract: Plastic injection moulding is considered as one of the very challenging processes to obtain output with a good quality and low cost. This paper presents a case study of the deployment of Six Sigma in plastic injection moulding to improve the quality of the final product by eliminating major defects occurred using cost effective methods. The main objective is to identify the major quality problems and to eliminate root causes by adopting Six Sigma define, measure, analyse, improve and control (DMAIC) methodology. The proposed Six Sigma approach effectively integrates quantitative and qualitative tools such as statistical process control (SPC) charts, Pareto chart, histogram, Ishikawa diagram, measurement system analysis, hypothesis test and checklist to achieve the desired goal. The results reveal that the implementation of the proposed Six Sigma approach can reduce the rejection rate significantly. It is found that the quality of the final products is substantially improved in terms of sigma level which increased from 4.06 to 4.5 and the cost of poor quality (COPQ) is reduced by 45%.

Keywords: Six Sigma; define, measure, analyse, improve and control; DMAIC; statistical process control; SPC; injection moulding.

DOI: 10.1504/IJISE.2019.100165

International Journal of Industrial and Systems Engineering, 2019 Vol.32 No.2, pp.243 - 266

Received: 21 Apr 2017
Accepted: 09 Oct 2017
Published online: 14 Jun 2019 *

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