Solving Critical Quality Problems by Detecting and Eliminating their Root Causes – Case-Study from the Automotive Industry

Abstract

The article presents the results of using selected quality tools to detect and analyze critical quality problems of low-pressure hoses for car radiators and their root causes for their elimination. The research aims to analyze the nonconformities of the tested product, identify critical nonconformities in terms of frequency of occurrence, and analyze potential causes of their creation to propose effective corrective and preventive actions. The paper presents the use of such quality tools as the Pareto-Lorenz diagram, Ishikawa diagram, and 5 WHY analysis. It was identified that the critical nonconformities of low-pressure hose that should be addressed first are nonconforming insert mounting depth and crooked cut detail. It has been shown that most of the factors causing critical nonconformances are in the "man" and "machine" type of problem areas. They identified the root causes of the quality problems, which were the incorrect setting of the machine by the operator and a lack of frequent inspections of the machine’s technical condition. It was proposed corrective actions to eliminate the possibility of critical nonconformities due to their root causes.