Assembly analysis: it’s a matter of form, fit and function
11 February 2011
With 3D scan data processing technology, Schneider Electric has been able to improve its design and engineering by focusing on function as a major element of assembly analysis
Schneider Electric process improvement specialist Rus Emerick would probably endorse the maxim, ‘the whole is greater than the sum of its parts’, as it so aptly describes his company’s approach to product development. The concept, attributed to Aristotle among others, is at the core of an approach called ‘functional analysis’, which Schneider-Electric has embraced with enthusiasm.
According to Mr Emerick, functional analysis at Schneider took a “quantum leap” when it decided to implement the feature inspection capabilities of Geomagic’s Qualify software, which enables users to detect, create and inspect geometrical features for tasks such as calculating size, analysing fit, comparing 2D and 3D features, and measuring point-to-point and feature-to-feature distances and angles. Mr Emerick again:
“Instead of looking at dimensions of individual parts, we are now able to analyse functionality as a major element of an entire assembly’s analysis. We simulate how parts exist in the real world, especially how they relate to their mating parts. We’ve saved a lot of time and material by validating our predicted functional conditions.”
From the theoretical, to the real
Mr Emerick uses the simple example of a hole and a pin to explain how functional analysis works. It is difficult and time-consuming to measure all possible cross-sections of the hole, and the 2D measurements often don’t have a close relationship to the fit of a cylinder into the hole. The hole might also be constrained in its XY location relative to another location, which might have a bearing on the possible size of an inserted pin.
Feature inspection in Geomagic Qualify acts as a virtual pin gauge, describing the wall location and recalculating the largest possible diameter of a pin that will fit in the hole, all the while maintaining the original constraints. This gives users insight into the behaviour and fit of a functional cylindrical feature rather than just the centre location.
“When dealing with a part within an assembly, it’s the contact location, not the centre of the hole, that determines whether it will function with other parts as it is intended,” says Mr Emerick. “The ability to analyse fit takes contact datum out of the theoretical world into the real world.”
A surprising advantage of being able to analyse a system based on function is that many more parts can be accepted without compromising standards. That’s because an assembly often functions like a team, with the whole working together to overcome individual weaknesses.
“In many cases when individual parts are measured, they fail to meet tolerances,” says Mr Emerick. “But an assembly can distribute tolerances throughout the chain of individual parts, and the assembly meets Six Sigma standards. This has tremendous cost and material implications.”
A positive pyramid
Thanks to company-wide adoption of 3D scanning and processing technologies, functional analysis has had various permutations throughout Schneider. It drives a philosophy that Mr Emerick dubs “design anywhere, build anywhere, qualify anywhere.” The company uses 3D scanning and processing technologies to close the loop between physical products and their digital representations. The key tools are Geomagic Qualify for quality inspection and Geomagic Studio for digital reconstruction.
Implementing 3D scanning and processing at Schneider works a bit like a pyramid scheme, except in a positive way. Approximately 50 ‘super-users’ in seven regional centres – two in the US (Cedar Rapids, Iowa, and Columbia, Missouri), two in France (Grenoble and Angouleme), two in Shanghai, and one in Bangalore, India – head up training and implementation of Geomagic software.
The super-users combine an in-depth knowledge of Geomagic software with old-school inspection skills; or, as Mr Emerick would have it, they are “grizzled veterans who are the modern-day equivalents of the old-time fact checkers” - depositories of years of knowledge with a deep understanding of how things work. “They pass down the knowledge on how to do something ,” he says. “We’ve found that peer-to-peer mentoring develops the best users.”
At Schneider, 3D scanning and processing users are broken down into three categories: the ‘generalists’, who use Geomagic Review, a free inspection review tool, for evaluation and new product development; the ‘experts’, who use Geomagic Qualify for linear and GD&T part analysis, first and last article inspections (FAIR and LAIR), and basic reverse engineering; and the ‘specialists’, who use both Geomagic Studio and Qualify for complete part/assembly analysis, Cp/Cpk (process capability) analysis, reverse engineering, and providing instruction and mentoring.
Cross-functional convergence
The regimen is not only thorough, it spreads knowledge fast. Mr Emerick claims it took just six months after the introduction of feature inspection in Geomagic Qualify for the company to add functional analysis across multiple applications.
Under the ‘design anywhere, build anywhere, qualify anywhere’ approach, analysis results obtained with Geomagic software are put to work throughout the company. It’s one data set, with multiple users and multiple solutions. Applications include design and verification, FAIR, LAIR, reverse engineering and documentation replacement, tool validation for predicting wear and making repairs, and functional analysis.
“The combination of Geomagic software and our system of training allows true convergence across all cross functions of product development,” says Mr Emerick. “We can use the same data set to answer different functional questions: How well did the supplier do its job? Is tooling faithful to the design? Is the part engineered to specifications? Can parts and assemblies be manufactured efficiently? Was the tolerance analysis accurate?”
It was only recently that the answers to many of these questions were speculative. Now, using a single data set, deep functional knowledge is available throughout the enterprise. And, when it is time to replace a part, Schneider has a history of its 3D definition from each time it was scanned.
“Our virtual team around the world can see how different parts work with one another,” concludes Mr Emerick. “It’s not theory, but real-world facts displayed visually so all can understand. That has incredible company-wide benefits, including major reductions in time to market, and in the case of part evolution, faster return to market.”
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