Doing the knowledge

Knowledge-based CAD/CAM systems are dramatically reducing design-time and are likely to have a huge impact on productivity. Diane Palframan reports

Smart tools that produce products faster and more easily are the result of recent developments by the `big four’ suppliers of computer aided design systems.

Knowledge-based products were introduced 18 months ago by Dassault Systemes, with Catia 5, its latest CAD/CAM package. Catia 5 enables users to build rules and checks into their design processes, allowing any part to be modelled automatically to specified standards.

`This technology is going to enable companies to make the next leap in productivity,’ says Peter Marley, IBM market development manager for knowledgeware. `It’s a tool that every engineer should be using.’

Dassault claims its latest technology can be accessed by companies of all sizes. Users start by creating a few design rules, then progress to defining the product’s parameters, creating the geometry automatically.

About eight companies are using the software in production projects, and many Catia users, including automotive and aerospace companies, are providing an evaluation.

Krebs Engineers, a leading supplier of cyclone separators, with a workforce of 150 people, has used Catia 5 for about six months and has reduced design time for some parts by as much as 90%.

Marley says that Krebs has demonstrated Catia 5’s ease of use and affordability. `Catia 5 was built from scratch based on a vision of what the infrastructure for the next generation of engineering tool – not CAD tool – would be,’ he says.

Leading CAD/CAM supplier Parametric Technology Corporation is also developing `engineering tools’ rather than pure design systems. It recently added behavioural modelling to its Pro/Engineer system.

Mike Campbell, PTC’s director of technical product marketing, says this allows the CAD system `to do more of the engineering work’, and has reduced the time taken to complete tasks from thousands of hours to only a few. He cites a recent demonstration for a US aerospace company where it took six minutes to analyse the pilot’s view around the cockpit of a fighter aircraft.

Behavioural modelling uses engineering and functional specifications, and processes the information to create `smart’ models. These can then be optimised to meet one or more objectives automatically, for example, minimising weight while maximising strength.

This is faster than trying to refine a design until it meets the design criteria. `Behavioural modelling eliminates this process,’ Campbell says. `You specify your goals and what attributes can be tweaked and the system produces an optimal design. It is a tool that can be used on a daily basis and the result should be better designs.’

While Dassault and PTC are providing generic tools for developers, Unigraphics is targeting specific applications with its knowledge-based products. `We have a different approach,’ says Paul Brown, European marketing manager. `We are targeting industries where we can make an impact.’

One of these is plastic injection-mould making, for which the company has developed a MoldWizard module for its CAD/CAM system. Some users claim it has reduced the time to design mould tools from 30-40 hours to about four hours. Brown claims it has attracted 30 new customers in Spain in less than nine months.

Two other industries for which Unigraphics knowledge-based tools are now available are welding, and automotive die engineering. It has developed a tool with General Motors, which has cut 30% off die design-time.

Unigraphics has also added some knowledge and process automation to existing modules, for example its CAM software. Alstom Power, the gas turbine manufacturer based in Lincoln, which helped develop the new module, has been using it since the end of 1999.

Alstom has defined its standard manufacturing methods in the software, so operations can be selected as soon as preliminary design data is available. The company believes it will be possible to start machining components on the same day that the design is released, eliminating a three-month gap.

Structural Dynamics Research Corporation, the fourth big CAD/CAM company, is less enthusiastic about knowledge-based tools, which it believes are creating confusion in the market. Its new offerings include software for designing core and cavity models, and mould bases for mould tools.

Like Unigraphics, SDRC has recognised that there are common steps in the mould design process and has worked with mould-tool makers to develop a tool that takes designers through each step, automating as many tasks as possible.

The company is, however, trying to sneak ahead of its rivals in 3D annotation with a package called 3dDocCom. Found in the latest version of I-Deas, this allows solid models or assemblies to be annotated with all the information required for manufacture, and eliminates the need for 2D annotation and paper documents. The models can be viewed over the web.

`We developed this in response to some of our more dynamic customers, like Ford, who want to remove drawings from the critical path of product development,’ says Guy Wills, SDRC European technical marketing manager.

Another of SDRC’s developments, aimed at the automotive industry, is a tool that can quickly convert scanned data points on clay models of car bodies into surface models. `We use polygon modelling, which is an emerging technology, to create polygons across all the point data,’ says Wills. `The polygons are then shaded and within minutes users can see if the resulting surface is what is required.’

SDRC expects polygon modelling to become a mainstream tool for other applications such as finite element analysis. A part could be scanned and a surface of polygons created which becomes the mesh on which an analysis can be performed.

`We have cracked a lot of the basic technology to allow millions of points to be handled very rapidly,’ says Wills.

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