APING T E FUTURE
Page 54
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Merrick Taylor, managing director of Motor Panels, talks of his company's innovations in computer-aided design.
• Motor Panels (Coventry) is now building some 550 cabs a week. This record level of activity at MP's Holbrook Lane plant comes as something of a surprise to those bombarded through the 1980s with gloomy news of Britain's truck industry.
For example, Seddon Atkinson's 400/ 401/411 cab, produced by MP throughout its 15-year life, has gone, to be replaced by the Strato range's Enasa-Daf Cabtech design, with negligible British content. The formation of Leyland Daf has led to a drop in demand for the C40 family of cabs, as the Dutch-made 95-Series heavies take over from Roadtrain models for premium business. The recent demise of the TL11-engined Cruiser and the discontinuing of numerous Scammell chassis has also reduced the call for C40 cabs.
On the plus side is the Roadrunner's success, which has meant a lot of new business for MP.
The C44 Roadrunner cab now accounts for the bulk of its production at Coventry, where the panels are pressed and the cab shell is assembled. From Seddon, the 211 and 3-11 chassis models provide important supporting cab business for MP, alongside C40 cabs for all Leyland models above Roadrunner size.
MP's managing director Merrick Taylor is bullish about the company's future cab business. Last September Motor Panels was bought from its parent Rubery Owen group for £7.5 million by the fast-growing CH Industrials group. CBI's other interests include Aston Martin Tickford, whose vehicle design and development skills could be useful in future joint projects with MP.
INITIATE PROJECTS
For over a decade it has been MP policy to initiate cab development projects from the earliest design stage. Futuristic concept cab mock-ups appeared on MP stands at motor shows in the early 1980s, but when MP unveiled its Hemi-Tech concept cab in 1984 it was a serious attempt to point the way to likely cab development for the rest of the century. Capable of being built from either steel or aluminium pressings, it was adaptable for production in unsophisticated Third World markets, while incorporating new weight-saving materials, including acrylic plastics, in its European market guise.
Light, simple upholstery materials and a spaceframe seat construction broke new ground, as did the Hemi-Tech cab's solid state VDU-based instrumentation. Taylor points out that although MP is not equipped to manufacture cab interior equipment and fittings, the company's design function extends far beyond the cab shell.
Under the CHI group banner, MP's engineering design role has been reinforced. As Taylor puts it: "We bring together innovation and flair on the one hand and modern technology on the other."
A team of stylists create the concepts, which can now be translated into a more tangible form using the latest CAD (computer-aided design) techniques. MP is in the forefront of CAD methods; last autumn it set up a design research centre with IBM United Kingdom.
RESEARCH AND DESIGN
Taylor sees this centre not only as a vital design and development tool in its own right — but also as a way of widening the scope of MP's own research and design activities, independent of specific truck manufacturers' projects. To some extent it has also freed MP from the shackles of confidentiality which restrict all vehicle component suppliers — especially those whose OEM customers compete with each other. Major design projects can now be completed more quickly starting with a clean sheet of paper or, more accurately, a blank screen.
For its part IBM can use the centre to develop new software programs and computer application techniques close to a real-life engineering and manufacturing environment.
In Taylor's view, CAD and CAM (computer-aided manufacturing) methods are of keen interest to many truck operators. He feels it is important for MP to get as close as possible to those endusers who inevitably influence the future of vehicle development and design. At motor shows and other events MP seeks feedback from truck owners and drivers.
CAB TRENDS
Which way is cab design moving? There can be few observers of the truck scene with a closer eye on cab trends than Taylor, whose involvement with the Design Council award scheme last year brought passing fame on television.
Aerodynamics will become an ever more significant influence, he asserts. The drive for lower drag coefficients suits plastics as the double-curvature contours can be achieved at much lower cost in a plastics moulding than an elaborate steel pressing. Also, sheet moulding compounds of the kind used in the hot-pressed outer panels of ERF cabs for the past 15 years are likely to be used increasingly for subsidiary (semi-load-bearing) items.
However, most of Europe's volume producers can justify the cost of tooling for steel pressings, and steel's vulnerability to corrosion has largely been overcome, says Taylor. For example, many MP cab pressings are Zintec coated to a thickness of 7 microns. Doors are typical ly treated on both faces of the inside skins, and the inner side only of the outer skin, leaving the exposed part of the door untreated, which enables MP's cathodic electrophoretic paint process to be applied successfully to the outer surface (the paint keys best to bare metal).
Taylor reckons that steel will remain the staple material for volume-produced load-bearing cab shells. Aluminium is too expensive, despite its weight-saving and corrosion-resisting benefits: aluminium prices have risen over twice as fast as steel prices since 1983. In the USA, says Taylor, where aluminium is cheaper, it is used for cab structures to cut weight easily without major redesign. In Europe, cab shell weight savings are now achieved instead through CAD/CAM methods.
LARGER PANELS
One way in which weight is being saved is by eliminating the structural (welded) joints. Cabs designed in the 1980s are notable in being fabricated from fewer, larger panels. The C44 Roadrunner cab built by MP illustrates the trend, as do a number of recent cabs on imported vehicles like MAN's F90/M90 range.
Bigger pressings and fewer joints also give a more rigid shell, with more predictable deformability in an accident. Potential sources of corrosion, along spot-welded joints, are reduced, and assembly is simplified, in the Roadrunner's case without the need for an elaborate jig. The C44 cab's side pressings, including the door surrounds, are each pressed in one piece.
There are important repair implications, however. Where damage is localised it is likely that the new larger pressings will have to be cut, to replace just one section. Cab designers now assume that most body shops are equipped with modern portable cutting tools and that their welds are of a high quality.
Larger sheet-steel cab shell components need bigger presses to produce them. As part of a £7 million investment at Coventry, MP is installing four new 1,600-tonne presses. The bed area, which limits the size of panel produced, is up from 3.17 x 2m on the older presses to 3.7 x 2.54m on the new models.
0 by Alan Bunting