Riassunto analitico
Today, the business environment is complex, dynamic and strictly interdependent and therefore calls into question the limits of traditional approaches. Along the product development, traditional procedures, processes, tools and design mentality must evolve, not only to manage this complexity, but also to profit from it.
For the aforementioned reasons, the drawing-based process (the actual common method for design, produce and measure products based on 2D drawings) no longer meet these demands.
Model-Based Definition (MBD) is a very promising innovative design approach to address the growing complexity of systems while reducing the time, costs and risks related to the development and distribution of these systems. Model-Based Definition creates complete technical data packages (TDPs), including the 3D model and associated data items, which offer a complete product definition and can be communicated and used effectively by all downstream customers, without the need for 2D drawings. These packages constitute a single data source useful to query, analyze, build and inspect the product.
In this scenario, CAT (Computer Aided Tolerancing) tools, for tolerance analysis, take advantage of the MBD approach, confirming as crucial part of the design process. Tolerance analysis or dimensional variation analysis (DVA) is a way of understanding how sources of variation in part dimensions and assembly constraints propagate across parts and assemblies, and how that total variation affects the capability of a design to achieve its design requirements within the process capabilities of manufacturing organizations and supply chains. Furthermore, tolerancing directly influences the cost and performance of products. There are, mainly, two approaches in DVA: Worst Case Analysis (WCA) and Statistical analysis (RSS).
The thesis wants to show the advantages of using statistical dimensional analysis in High Performance Engines design, i.e. new Lamborghini V12 engine. The study has been performed through a Sigmetrix’s CAT tool: CETOL 6σ.
The purpose of the analysis has been to guarantee the mountability of the parts, to ensure the performances of subsystems or components and to reduce the costs, modifying the tolerances. Furthermore, it has produced a greater understanding of the tolerance’s values and the verification of the correct GD&T rules application (fundamental in an increasingly globalized world).
The results show the importance of performing the appropriate DVA activities, early, in the design cycle in order to achieve a more rapid and robust release of the product. Moreover, it highlights that the tolerances can be safely increased, compared to a manual WCA spreadsheet analysis, without losing the functionality of the part.
Finally, as future developments, it could be useful to implement the real statistical distributions of tolerances to optimize the results getting closest to the reality.
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