QUALITY IN MANUFACTURING
Two industries - same problem
16 October 2015: Tom Stewart, Q-DAS Inc.
Considering that the prevailing quality standards (means, methods and traditional statistics) are oriented towards the automotive industry and its traditional manufacturing systems, it is surprising that even within the automotive industry there is significant disagreement and in some cases outright confusion about the definition of the major quality metrics. This has led many companies to author their own company guidelines in order to clarify the statistical assessment of measurement systems, manufacturing tools and process capabilities. These company guidelines mainly deal with the blind alleys left open to interpretation in the prevailing guidelines, bringing definition and acknowledging the need for engineering judgment based on pragmatic analysis. Lost in the discussion are several key points that are industry specific.
As it relates to the aircraft industry, the fact that these machining production systems will produce fewer parts with more frequent pauses in production means that the traditional automotive quality metrics, especially those that assess process stability, may not be sufficient to accurately describe the process or provide the information necessary to improve a process. Also unique to aircraft production are the exotic materials and the extensive use of general purpose tooling and machines, such as flexible milling, turning, boring and drilling machines, which lend themselves to the manufacturing of multiple part characteristics by a single tool, where not every characteristic has the same level of criticality. Advances in carbon fiber manufacturing materials and processes still continue at a fast pace and these processes are unique enough to warrant special attention on their own as it pertains to descriptive statistics.
As it relates to the automotive industry, governmental environmental regulation and standards have driven powertrain manufacturing away from steel and iron towards the successful development of exotic materials for manufacturing lighter and more fuel efficient powertrains. For automotive body and assembly the now extensive use of polymers, Die cast and thin wall stamped body parts means that they too have made significant advances in manufacturing technology.
Ironically, automotive now has more in common with the aircraft industry than at any point in history and both still have the same significant gap when it comes to dealing with data collection and analysis (quality metrics) for purchased components...