Application of Selective Assembly as an Aerospace Design for Manufacturing and Assembly Principle for Effective Variation Management in Aerospace Assemblies

Aerospace engine parts are complex precision-engineered products with tighter assembly tolerances produced by conventional and non-conventional manufacturing processes. Variations in these manufacturing processes have to be controlled, process risks mitigated, and managed effectively, to facilitate the ease of aero-engine assembly to reduce overall variation and improve the assembly quality. One such technique is the application of the Selective Assembly as a Design for Manufacturing and Assembly (DfMA) tool. The paper details the methodology of Selective Assembly, its applications, benefits, and limitations in the aerospace industry along with a framework case study with a focus on ease of assembly and meeting the design intent of the assembly fit with the detailed study on the current traditional assembly process. The focus is to analyze the current challenges faced on the application of the Selective assembly of Aero-engine components through a case study on the development and application of an Assembly Installation Operation Selective (AIOS) assembly tool, that be applied both as a built-in tool for Selective Assembly data acquisition and optimal selection. The study also investigates whether the concept of decimal roundoff in the measurement reporting process has any significant impact on the selective process capability and the pin-hole assembly fit quality. The objectives are to optimize and enhance the current assembly process to meet the customer design intent and First Time Right (FTR) quality of the assembly fit and to promote the application of the Selective Assembly concept as a potential quality and cost optimization technique in assembly processes highly subjected to variations by emphasizing its application as an Aerospace Design for Manufacturing and Assembly (ADFMA) guideline for effectively controlling and mitigating assembly variations of shafts and holes in aerospace engine parts and reducing reworks and rejections in the aerospace industry due to high process variability and need for better process control in fabrication tolerances.