Finding and eliminating the root cause of defects identified in customer complaints

Abstract

Volvo Cars is a global car manufacturer that produces premium brand cars that demand high quality. The quality of a product is often defined by the degree of customer satisfaction. Therefore, Volvo Cars Corporation has internal departments working with customer complaints. This thesis was performed in collaboration with the department Variability Reduction Team who perform root cause analyses initiated by customer complaints on newly produced cars. A case study was performed regarding a customer-initiated problem with loose support bearings at the production plant in Torslanda. People from several different departments possess different knowledge and experience regarding the problem with loose support bearings. Therefore, cross-functional collaboration was essential for the success of this project. In addition to finding the root cause, learnings from the case study were also generalized into recommendations to future projects. Initially, the existing knowledge about the origin of the problem with loose support bearings was limited, and many short term solutions were used. Some of the implemented short terms solutions lead to additional waste in the form of non-value adding activities. For example, additional controls, replacement of defect support bearings, rework, and administrative work. The root cause is confirmed to be within the production concerning the alignment between the car body and the equipment assembling the support bearing. By making the production process more robust and increasing its reliability, the perceived quality of the car is increased, and high customer satisfaction is maintained. The case study follows the DMAIC methodology from Six Sigma, which is similar to the problem-solving methodology used internally at Volvo. Therefore, improvement areas were defined based on factors that the authors experienced hindered efficient problem-solving. To solve these challenges and decrease their impact, recommendations were given to Volvo within the four areas: base decisions on facts, standardization, knowledge sharing, and also communication and collaboration. Using these recommendations and thereby making the problem-solving process more efficient could enable a more beneficial resource allocation and better root cause analyses.