A Statistical Process Control Technique for Reducing Product Non-Conformities: A Case Study of Production of Crossover

The aim of this paper is to use statistical process control technique to reduce non-conformance in the production process of crossovers. In the machine shop of the case study company, there has been issues of large number of non-conforming crossovers after carrying out magnetic particle tests at the final inspection stage. This resulted in waste of resources associated with increased scrap production, reworking of non-conforming product and waste of time. As a way of improving quality of crossovers produced, this research adopted the use of PChart which is a Statistical Process Control technique for analysing inconsistencies with machined crossovers through a period of 5years. Results from the five consecutive years (2014 – 2018) show that 7 points out of 12 points fell out of control limits in 2014, 9 points out of 13 points fell out of control limits in 2015, 6 points out of 11 points fell out of the control limits in 2016, 7 points out of 14 points fell out of the control limits in 2017 and 4 points out of 14 points fell out of the control limits in 2018. These results show that the process was a faulty one and there was need to improve on it in order to reduce the number of non-conformities to the barest minimum. This study reveals that materials from the supplier needed to be inspected to ensure there were no hidden flaws (cracks). This is capable of reducing defective products thereby making the crossovers conform to customer specification.