Time-to-market pressure has never been greater, which is why new technology to shorten this critical process is becoming more impressive

Years ago, the beginning of any new automotive project was called the ‘fuzzy front end’. No one really knew how much time would be required to convert concepts into designs and designs into prototypes.

Today’s fiercely competitive global automotive market has changed all that. The concept, design and prototype stages of nearly all production road vehicles are identified and scheduled years in advance, so that no model has the opportunity to become outdated. The alarming fact is that consumer demand for exciting new designs means that the allotted time to realise new models is becoming ever shorter as OEMs continually try to capture greater market share.

Design is more important than ever as global carmakers work to reinvent their businesses and meet consumer demand for more sustainable vehicles. Today’s carmakers are tasked with revolutionising their product line-up to address both greater fuel efficiency and alternative fuels – all with the expectation that the next generation of cars will also be affordable.

Cost-saving prototype design

Of course, design doesn’t just apply to the vehicle chassis; it applies to literally every component, from the engine to the tyres, a fact recognised by 2D and 3D design specialist Autodesk, and one of the reasons why the company made its debut appearance at the 2008 Paris Motor Show last October. Autodesk’s participation reflects its focus on providing a solution for digital prototyping that helps automotive industry manufacturers to better conceptualise, model and test designs before they are built, thereby reducing costs and accelerating time to market.

Autodesk 3D visualisation software solutions enable customers, which already include French automotive design firm Estech and sports-car manufacturer Venturi Automobiles, to implement a fully-digital design process.

The tools reduce the development costs of future models, as the choice of production is not based on expensive physical prototypes but on digital prototypes that can be explored and modified at any time. Automotive engineers can also use Autodesk’s digital prototype to predict how products can be disassembled for end-of-life recovery and recycling.

Autodesk has announced that Bentley Motors has chosen its digital prototyping solution for designing its next-generation automobiles. The prestige carmaker predicts it will cut design times in half, because as Jeff King, Digital Data Manager at Bentley says, “Being able to create accurate, realistic rendered images in this way gives us the opportunity to review designs and test the market at an earlier stage without physical prototypes.”

While chassis, engine and wheel components are obvious targets for digital design/prototyping processes, concepts such as vehicle fabrics and textiles can also be generated in the same way using products such as Lectra’s latest version (V4R1) of DesignConcept Auto.

Equipped with this solution, carmakers looking to cope with increasing customer demand for greater numbers and heightened complexity of seats can create virtual models, run feasibility analysis reports, develop templates and estimate costs, resulting in reduced time-to-market of finished products. One of the new benefits of version V4R1 is the automatic marker-making module, which estimates fabric consumption and related costs according to the customer’s business model.

Vistagy is another technology supplier active in this area. Seat Design Environment (SDE) 2.9 is the latest version of its 3D development software that is tailored specifically to the design and manufacture of seats for vehicle interiors.

It can be integrated directly into popular commercial 3D CAD systems for more efficient management of all aspects of seat trim development – from conception, design and cost modelling to document generation and manufacturing.

SDE addresses this need by enabling engineers to create a single, complete 3D virtual product definition of the seat architecture and cover – including all non-geometric data associated with the model, such as material specifications, stitch types and sewing instructions. This single master CAD model helps auto engineers efficiently share design detail across teams, obtain instant feedback on constantly changing design and cost data and automatically generate critical manufacturing documentation. As a result, OEMs and suppliers accelerate seat delivery time from months to days while eliminating physical prototyping, improving manufacturing accuracy and assessing how the trim interacts with the seat architecture and, ultimately, the entire interior.

Let’s get physical

The term ‘rapid prototyping’ has prevailed for more than a decade. Its enabling technology continues to be exploited by the automotive community, but what happens when there is a need for more than just four or five prototype parts? What happens when, say, 1,000 parts are required? In automotive terms, 1,000 hardly represent high volume.

Stratasys is establishing a reputation for additive fabrication machines capable of producing plastic parts in quantities of this range. Its most recent introduction, the FDM (fused deposition modelling) 900mc, is creating quite a stir, with 17 orders already secured. Stratasys says that manufacturing engineers in the automotive sector are among the first adopters of this new DDM (direct digital modelling) technology, with the most popular applications being fabrication and assembly tools.

Stratasys says that technology innovation led to advances in the machine’s precision. The FDM 900mc is based on a new platform, distinct from previous FDM additive fabrication systems used for production or prototyping.

The head gantry is driven by ball screw technology as opposed to previous machines, which are belt driven. This results in a marked improvement in predictability and repeatability. The resulting positional accuracy and part tolerance are substantially improved over previous systems.

Recognised manufacturing industry expert Graham Tromans, from Loughborough University in Britain, operates a consulting, design and production centre consortium to assist manufacturers. The programme employs an array of fabrication processes. “We are impressed with the FDM 900mc and the potential it opens up for automotive manufacturers. It has high accuracy, repeatability and build speed. We think it’s well positioned for direct digital manufacturing.”

Stratasys and other additive fabrication system makers expect the market for DDM applications will eventually far surpass the market for rapid prototyping and 3D printing applications.

3D printing

Current trends continue to support the growth of innovative prototyping techniques such as 3D printing. Z Corp’s new ZPrinter 450 3D, for example, is designed for use in an everyday office environment as it eliminates nearly all of the hazards, waste, noise and disposal issues that are associated with typical rapid prototyping systems.

Continental Tire North America is one of the latest to benefit from Z Corp 3D printing solutions, adopting the technology when it wanted to quickly generate multiple tread samples for timely product development decisions.

From all the initial concept drawings, designers at Continental developed six into fully-fledged 3D CAD models. Although tyres may seem like simple items, they are in fact quite complex to design. Most tyres sport a torus shape – they have a curved circumference and curves in the cross-section. To simplify and accelerate design work, Continental developed proprietary modelling software called TireWizard that operates on top of its Unigraphics NX 3D CAD software.

Moulding the future

Midas Pattern Company’s new moulding process – FLEXrim – is for the rapid prototyping of heavy section, rubber-type mouldings. FLEXrim uses an enclosed mould process to quickly prototype large items such as floor mats, bumpers, infill and over-mould applications.

The flexible mouldings can weigh up to 30kg and measure up to 2,000 x 1,000mm. Undercuts and wall thickness from six to 25mm can be accommodated and mouldings can be painted to replicate in-mould textures.

FLEXrim is a development of Midas’s FASTrim process, a competitive alternative to SLA/SLS/ silicon and VAC casting, which produces finished parts using cast polyurethane (PUR) and soft tooling CNC machined directly from 3D CAD data.

Continental now recognises the value of turning C models into rapid physical prototypes that employees can hold in their hands while evaluating design alternatives.

“Although a 3D CAD model is very vivid, it just doesn’t tell you as much as a physical model can about what will come off the production line,” says Matt Lamb a Continental tyre designer based at its plant in Charlotte, North Carolina.

Today the company runs its recently installed ZPrinter 310 System from Z Corp, which prints 254 x 127mm tread samples in just five hours.

The time savings become even more exponential when Continental opts to print three different samples at once.

“We now have more flexibility in the design cycle to develop, discuss, debate and refine tread designs that will ultimately best satisfy our customers,” says Lamb.

In a further boost for users of Z Corp 3D printers, DeskArtes has launched ZEdit Pro 1.0 software in co-operation with Z Corp and its distributors. ZEdit Pro offers easy-to-use and specialised model repair for Z Corp 3D printers as well as full model colouring and texturing functions. Every new Z Corp 3D printer customer will get a copy of ZEdit Pro software included in the purchase.

It remains to be seen whether popular rapid prototyping techniques such as 3D printing continue to thrive in the wake of new processes such as direct digital manufacturing.

One certainty, however, is that the need to get from art to part quickly and effectively will only grow in stature as market forces continue to squeeze lead times and drive down development cycle times.