Potentials for Horizon 2020
Factories of the future (FoF-08-2015)
Currently under evaluation
Submission date: 4th of February
The GMσD project:
What is a Manufacturing Variation Database?
The axiom of manufacturing imprecision states that:
“All manufacturing processes are inherently imperfect and produce parts that vary”
This variation means that the size and shape of a part is never exactly as intended. This can result in many quality related problems such as, parts that cannot be assembled, excessive play in mechanisms, products not performing as expected etc. Poor understanding and quantification of production variation not only affects the quality of the product for the user, but it can have major costs associated, such as product recalls, service, maintenance and even legal charges… but these costs are just the tip of the iceberg!
These visible costs in the market place are somewhat preventable. By specifying tolerances limits so the part or product always achieves the desired performance, non-functioning defects can be removed during quality control. However, what lies beneath are the consequences to the organisation when the tolerances specified are tighter
than the achievable variation, resulting in:
- High manufacturing scrap rates (materials costs, time delays)
- Excessive measurement and inspection processes (resource intensive)
- Delayed product launch (opportunity costs)
- Long ramp-up times (opportunity costs)
In order to prevent quality and reliability issues, Design, Production and Metrology need to be able to convey their requirements and capabilities back and forth, effectively. Over the last 20 years, standards committees such as the ISO/TC213 have made great progress in introducing GPS - Geometric-Product-Specification (ISO/TS 17450-2, 2002) enabling engineers to both specify and verify geometric features without ambiguity. This has made a huge advancement in preventing unknown quality issues reaching the market place.
Design engineers are now able to dimension and tolerance all geometric features with precision and clarity. Metrologists are armed with equipment and the approaches to measure and verify the geometry, also with the ability to precisely estimate measurement uncertainty. However, the link from production to design has yet to benefit from GPS and at present there is no standard for estimating manufacturing variation of geometric dimensions as indicated in the figure on the left. As a result, designers often use out-of-date linear tolerance guides such as the ANSI B4.1. Not only are these inaccurate for many processes, but they cannot be applied to geometric tolerances, angles, surfaces or anything other than very basic linear tolerances.
It is vital that industry is able to close the quality loop between design and production through accurate data regarding variation of geometric dimensions for different processes. Such knowledge allows design engineers to design in quality and robustness to their products, production engineers to make well-founded decisions on manufacturing technology, and metrology experts to ensure that quality is appropriately controlled throughout the value chain.
To make this vision a reality for Europe, the GMσD (Global Manufacturing Variation Database) project aims to revolutionise our current knowledge of manufacturing variation as well as practices for its management. Through reference to the widely used ISO Geometrical Product Specification annotation, the GMσD project and database
will initiate the creation of a new standard, relating the description of manufacturing variation to geometric dimensions.
The figure to the right shows how companies that adopt the new approach will capture live data on manufacturing variation from their production lines. This data will be stored in their Private Manufacturing Variation Databases (PMσDs), replacing/supplementing current process capability databases.
Data from the PMσDs will then be anonymized and aggregated into a Global Manufacturing Variation Database (GMσD) providing data comparable across processes, industries, materials, regions, suppliers and a wide range of product geometries. Through the creation of a global database, the development and integration of advanced analytics as well as software interfaces, the GMσD project will provide a quality-focused information management system and a Big Data approach for R&D, production and supply-chain management. The results will transform our ability to manage variation, to allocate tolerances, to benchmark a company’s quality performance, take effective outsourcing decisions as well as to certify process capabilities.