Advanced 3D software technology that simulates and visualises geometric variations that will be caused by manufacturing processes is enabling automotive manufacturers to deliver higher perceived quality while saving development time and costs.
As people become more demanding in what they expect from the manufacturers of their motor vehicles, so the question of perceived quality becomes ever more important. In this context, perceived quality is the impression of quality that a customer gets when first viewing a new vehicle, before considering its functionality. Perceived quality is therefore inextricably tied into the design, engineering and manufacturing processes.
Every product that is manufactured and assembled is subject to some degree of geometric variation. That’s the nature of the production process. Understanding variation, by accounting for the capabilities of existing or proposed manufacturing processes and by calculating accumulated tolerances and the effects these will have on the form, fit and function of parts and assemblies, is therefore a crucial aspect of the design, engineering and manufacturing process – and of achieving consistently high perceived quality.
Although the automotive industry has undoubtedly made great strides in improving the perceived quality of passenger cars and vans over the years, the process of checking the result of the stack-up of design tolerances and variation typically takes place at a relatively advanced stage of the design and development process. This has its drawbacks.
It can introduce a loop from the development and engineering phases back into the concept design and styling phase, causing delays and adding to the design costs. Or by the time it’s carried out, it might be considered too late, too costly or too disruptive to optimise the design surfaces to meet the dimensional variation requirements. So perceived quality will be compromised.
Bridging a gap
In recent years a new type of software, known generically as ‘3D virtualisation’ software, has been developed specifically to address the matter of perceived quality. It creates high-quality visualisations of a new product, not in the nominal, as-designed form of its 3D CAD model but as it will actually be manufactured, complete with all the variations in gap and flush, as well as buckling and twisting, that will affect its appearance.
This enables designers, engineers, quality and manufacturing personnel to more readily reach agreement, as early as the concept design and styling phase, on the acceptable level of geometric variation that will still deliver high perceived quality. This, in turn, shortens development timescales and reduces costs through fewer late design changes, fewer physical models and more right-first-time tooling.
This 3D virtualisation software, of which aesthetica from UK-based software developer Icona Solutions Ltd is the first example, therefore bridges the gap between what traditional design visualization software on one hand and tolerance stack-up and analysis software on the other can each deliver individually in the area of perceived quality. It ‘virtualises’ the final manufactured product in a high-quality 3D visualisation environment – long before the manufacturing process starts.
Logical process flow
Before looking at how this new type of software is being used today by some of the world’s leading automotive OEMs, let’s look at the ways in which it can be applied at the various stages of the overall concept-to-production process.
The starting point for variation analysis and perceived quality studies using 3D virtualisation software is the 3D digital product model. This is imported from an industrial design system or a 3D CAD system using industry-standard or de facto 3D data transfer methods.
Once in the 3D virtualisation environment, the appearance and finish of the various parts of the model can be defined using the software’s materials library. This includes accurate car paint materials, including metallic and pearlescent finishes, bump-mapped materials with natural and technical grains and glass with accurate reflections and refraction. It also includes material properties. The user simply selects a part and assigns to it the appropriate material finish and its physical properties.
How this model is then used depends on where in the vehicle design and development process the user is sitting: what needs to be achieved in terms of perceived quality and what needs to be done to achieve it.
Concept design & styling
At the concept design and styling stage, perceived quality targets can be set and reviewed and the maximum acceptable level of variation between all visible components can be established. This is an aspirational activity. Alternative variations between components can be tested and compared with competitor data to establish what level of perceived quality is required to maintain the integrity of the design. This is often an iterative process where many combinations of gap and flush variation can be applied to the early digital model.
During this process, the software allows for variation targets to be re-created and visualised very quickly and to be modified to display results instantly. This is ideal for live discussions and perceived quality forums.
During the vehicle body and trim requirements phase, concept location and tolerance schemes are applied to the Class A surface components to create a simple tolerance chain. This is used to 'test out' the capability of various designs or assembly solutions to meet the targets established in the earlier target setting and review process.
Beginning this activity early in the design phase of the vehicle’s development can allow for the surfaces or styling to be optimised or de-sensitised to accommodate the effects of variation and obviate the need to increase targets or reduce component tolerances - both of which are undesirable. It also allows a set of variation-related requirements (locators, tolerances and body structure variation) to be established and delivered into the engineering process.
This could be considered a pro-active approach to resolving dimensional variation issues where the parameters of the design are identified and the requirements are known upfront.
At some stage in the engineering process it will be necessary to validate the design to ensure that the initial requirements for Class A surface location, tolerance and body structure assembly variation have been met. If it has not been possible to meet the initial requirements, perhaps due to cost or conflicting design analysis constraints, alternative inputs can be quickly tested out on the 3D virtualisation model. The resulting variation can then be analysed to give instant insight to the consequences of engineering decisions.
By the time the actual manufacturing stage has been reached, issues that will affect perceived quality should have been resolved. However, should a perceived quality issue be identified only when the manufacturing process has begun, the 3D virtualisation model can again be used to assist in resolving it.
By replacing the component or assembly tolerance inputs in the model with measured manufacturing data from the shop-floor, the identified issue can be replicated. This will then allow proposed solutions to be very quickly and cost effectively tested out to establish the most appropriate method of resolution without the time, disruption and expense associated with physical trials.
But even when no issues arise during the manufacturing process, the real world measurement data gathered on the shop-floor can be extremely valuable at the next model refresh. It can be used during target-setting and early perceived quality studies on the refreshed design – or on the next model in the range that is to be built on the same platform.
At Nissan Design Europe’s headquarters in London, the use of aesthetica 3D virtualisation software during the design of the Nissan Qashqai enabled the development teams to uncover issues in their design review sessions that almost certainly would not have been discovered under their earlier digital processes. In fact, they were able to interactively visualise tolerance conditions and manufacturing criteria that previously would most probably have had to wait until the first physical build in manufacturing, using production tooling. And it goes without saying that mistakes at this late stage are not allowed!
During the design and development of the award-winning Opel Insignia at General Motors’ International Technical Development Centre in Rüsselsheim, Germany, aesthetica 3D virtualisation software was used from the early concept design stages. This enabled the various design, engineering and manufacturing disciplines that were involved to understand the manufacturing constraints and to agree on gap and flush conditions and manufacturing tolerances as early as possible in the process.
Edgar Lossnitzer, manager of the dimensional management department at Opel states, ”Since introducing aesthetica into Opel there have been no more long-winded and time-consuming discussions regarding a few tenths of a millimetre. Communication to management of necessary changes has improved, decisions are made faster and as a result, development costs are saved. Considerable resources have also been saved by eliminating the need for physical validation models.”
At FIAT Group Automobiles, S.p.A., aesthetica 3D virtualisation software forms an important and integral part of the company’s overall product lifecycle management (PLM) software environment.
“Typically, variation analysis is performed at a fairly advanced stage in the design process and is often too late to influence the design”, says Dr. Elena Bergadano, engineering quality and craftsmanship manager, FIAT Group Automobiles S.p.A. “However”, she states, “by using aesthetica we are able to actually see the effect that manufacturing variation will have on perceived quality, exactly as the customer will see it. This enables us to identify and resolve aesthetic problems at a much earlier stage than has ever been possible before. We can work directly with the design teams to ensure we drive up perceived quality”.
By using the software to apply information on tolerances and locator schemes directly to the 3D digital model of a vehicle, Fiat’s engineering teams are able to simulate and to visualise, in real time, their effects on components and assemblies in terms of form and position variation and component deformation etc. Root cause analysis allows them to diagnose the cause and quickly try out what-if solutions.
Meanwhile, in China Great Wall Motor Company implemented its new ‘Three Hs Strategy’, addressing ‘High-luxury’, ‘High-performance’ and ‘High-tech’ early in 2011. As a part of this strategy, Great Wall formed its new Dimensional Management Group and implemented aesthetica 3D virtualisation software as a core tool for helping the company achieve the goal of ‘High-luxury’ throughout its vehicles range.
Great Wall’s principal aim in implementing the software is to improve the perceived quality of its vehicles by reducing the average exterior gap dimension on all its high-end luxury vehicles.
The software is used by Great Wall at all stages of the vehicle design and development process, from the concept phase, where it is used in setting the dimensional technical specification, i.e. gap and flush targets, through the early and advanced engineering phases for optimising locator strategies, to the detailed engineering and manufacturing stages for the visual analysis of tolerance stacks and for root cause analysis of perceived quality issues.
Although relatively new to the market, there is no doubt that the development of 3D virtualisation software is already helping automotive OEMs to drive up the perceived quality of their vehicles, without adversely impacting manufacturing costs. Indeed, there is ample evidence that its use saves time and costs.
For example, one major OEM identified savings of over $875,000 on one vehicle programme alone through less re-tooling, fewer physical models and a shorter development time-line.
Another realised immediate cost savings of over $100,000 a year on an existing vehicle - and also discovered something that numerical analysis alone had not revealed: that over 20% of its vehicles would have unacceptable gap conditions. Design changes could therefore be made to deliver improved perceived quality levels on its future vehicles.l