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While CAD/CAM software is best known in the plastics industry for its applications with injection moulded products, it is also used extensively for the design, manufacture and inspection of composite components for the automotive industry. It offers particular benefits in the development of parts where aerodynamics or ergonomics are key considerations and in the manufacture of all types of tooling, including moulds and patterns.
(Published on January-February 2006 – JEC Magazine #22)
BY PETER DICKIN, PUBLIC RELATIONS OFFICER, DELCAM PLC
The fundamental benefit of 3D CAD/CAM systems is the ability to define complex component designs without the ambiguity inherent in 2D drawings. Modern visualisation techniques mean that highly realistic and accurate images of the proposed concept can be generated on the computer. This allows everyone involved in the development, marketing and sale of the new design to make informed comment on the proposal throughout the product development process.
Basing product development on CAD/CAM models also smoothes the transition from initial concept to final product. The CAD/ CAM model provides a clear reference for all those involved in the process and, provided suitable data management systems are in place, ensures that everyone is working on the latest version of the design as it evolves. Automation of routine calculations, together with the “intelligence” built into the software, remove repetitive work, so reducing mistakes and giving the skilled engineers more time to refine the design.
2D from 3D
Recent developments for composites manufacture include new methods for the generation of 2D patterns for prepregs from 3D models of components, improved nesting to ensure the most economic use of materials cut from sheet, and an increased range of five-axis machining methods, both for the manufacture of patterns and tooling and for the trimming and drilling of moulded parts. In all these areas, the use of advanced CAD/CAM software enables companies to maximise their profitability by increasing productivity, improving quality and reducing lead times.
The new methods for the generation of 2D patterns from 3D CAD models within Delcam’s software are based on un-wrapping techniques first developed for the footwear industry to allow the cutting of leather shapes from shoe designs. They provide quick and easy methods for the creation of the prepreg designs needed for the manufacture of complex, curved shapes. The 2D patterns can then be arranged to give the most cost-effective use of material with new nesting functionality.
A range of five-axis machining methods is essential for efficient composites manufacture and finishing. Large patterns can be made more quickly with five-axis machining because of the shorter tools and faster cutting speeds that can be used. Newer CAM systems also support five-axis engraving of scribe lines to define the component boundaries on lay-up tools and five-axis profiling for trimming of the moulded part.
More powerful software
The ATR Group, one of Europe’s leaders in the design, development and manufacture of carbon fibre-reinforced composites, has adopted Delcam’s CAD/CAM software for the production of prototypes, patterns and tooling. The software is also used for two-dimensional design of prepreg fibre shapes from threedimensional CAD models.
Giulio Strambi, technical department Manager at ATR, explained that it was the move into higher volume production that prompted the first investment in more powerful software. “For many years, we used composite tooling but this is only suitable for a maximum of 100 or 200 parts,” he said. “When we began to produce some of our motorcycle components in higher volumes, we decided to introduce aluminium tooling and so started looking for the best software to machine the material. We undertook tests on a number of systems and the results indicated that Delcam’s more efficient machining strategies would give us higher productivity.”
Following this initial success, additional seats were acquired to replace the system previously used for the machining of prototypes and patterns for the composite tooling. “Five-axis machining of our patterns is now much more efficient,” commented Mr. Lupi, machine programming manager. “The software is also very easy to use for a five-axis package. Only a few days of training are needed so the extra seats could be implemented very quickly.”
Eric Schell said that the CADCAM software helps the company to meet its tight lead times. “We are able to determine if any problems will occur before we start any manufacturing by using the software’s analysis tools and can quickly complete new designs,” he explained.
“Similarly, with the CAM system, we have advanced our machining techniques and dramatically reduced costs and delivery times.”
Design versatility and class A finish
Australian company UP Industries has developed a fast-growing subsidiary making automotive styling kits, C2R, to complement its more established product design, pattern-making and toolmaking operations. Central to the success of this business is a unique composite tooling system produced with Delcam software.
Development of the system began from the expertise in urethane resin development of Mani Riederich, who founded UP Industries. Whilst aluminium, mild steel and cast steel moulds are used for producing large volumes of parts, the company recommends that customers use its composite tools for production runs between 100 and 2,500 units. Composite tooling can be produced at a fraction of the cost of steel or aluminium tools and offers good design versatility as well as a class A finish. The unique formulations used mean that there are few limits on size; the largest composite mould made by the company weighed 7 tonnes.
The C2R concept came about when UP Industries was faced with a quiet period in certain OEM contracts. “To tide us over the reduced amount of work, we decided that we should produce our own parts and use them to raise the value of some second-hand cars,” remembered Director Eric Schell.
“We then managed to sell our idea to Ford and were commissioned to produce front and rear bumpers and grilles for its Falcon AU model,” he added. The company completed the Ford kit in six months. “Once our extras were added on to the vehicle, the manufacturer saw an uplift in sales,” claimed Mr. Schell. “Since that success, we have become established as plastic surgeons to the local automotive industry, using our expertise to make cars more beautiful.”
Typically, the first stage in developing a new automotive component is generating the CAD/CAM model, which is either supplied to UP Industries by the customer or developed in-house. The composite resin cavity and core are produced from this model. A master sample is then produced to allow preliminary fitting of the part on a vehicle and so ensure that there are no design discrepancies. Only after this check is a complete tool produced.