A Systematic Approach to Inspection Planning in Agile Process Development of Hairpin Stator Production

Abstract

Given the globally increasing demand for electric vehicles, production capacities for electric powertrains need to expand dramatically. Therefore, the automotive industry is in need for technologies with high potential for automation and mass production. The innovative hairpin stator technology, in which the winding consists of solid copper bars instead of flexible round wires, promises unique and valuable characteristics on both the product and process side. However, major challenges need to be addressed and overcome to achieve a reliable and stable process for series production. Also, due to the cost-intensive and rather inflexible production lines, product and process characteristics need to be developed and defined at an early stage. One major challenge is the assurance of quality throughout the manufacturing process and especially the use of inspection technology in the course of the same. The goal is to develop an efficient inspection concept that specifically targets quality relevant interdependencies throughout the production process. Therefore, pre-identified highly influential process error sequences are analyzed based on learnings from early process development and expert knowledge regarding the respective process steps. Then, both potential inspection points in time as well as potential inspection technologies for the identified critical error sequences are evaluated. As a result, the analysis lists process errors and error sequences with critical impact on the quality of the finished hairpin stator and suggests inspection measures to address those parameters. In summary, this paper presents a method for the analysis of complex process chains in early process development and enables the integration of the results into the inspection planning for the pre-selection of the inspection point in time and technology.