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AN
ALL-ALUMINIUM Duncanmec tipper - chassis, body, rims as
light as is practically possible
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The acceptance of aluminium as a viable material in the trucking industry owes much to the truck, trailer and body manufacturing industries. Here is where the real craftsmen of the transport industry work. A visit to any aluminium trailer or truck body manufacturing plant is a walk through a latter-day renaissance in metal fashioning. Artisans, crafting an array of vessels from the versatile material are busy reshaping the future of truck transport. Between the welding sparks, metal guillotines and snapping rivet guns,
Paul Collings gets an inside look at what is busy pushing the tare mass envelope.
Based in Worcester in the Western Cape, GRW Engineering is a relative newcomer to the industry but has, in a few short years, made a name for itself with its innovative aluminium tanker designs. Marketing director, Stephaan van Eeden claims: "We're even using aluminium for our chassis. We've gone this route because of the drive to maximise payload. We use designs and materials like Xtral 5182 (an aluminium alloy imported from France) without compromising the integrity of the trailer."
He goes on to say that much research is being done to improve the tensile strength of aluminum. "With blended materials, aluminium can equal the tensile strength of mild steel. With these new alloys, trailers can get even lighter without compromising strength. For the transporter, the right trailer configuration will improve payload potential considerably."
Duncanmec's John Rivett-Carnac describes his new design: "Our new aluminium Spitzer dry bulk tankers are designed for long haul and can achieve a legal payload of 40 tons. The combination consists of a tandem axle semi trailer with a twin axle pup trailer. The total tare of the rig is 16 000kg, giving room for exceptional payload. If you take the 5% allowance into consideration, that's 42 tons of payload."
Man vs machine
Aluminium is not an easy material to weld. It has a lower melting point than steel and requires a steady hand to execute a safe welded join. In the transport business, there can be no room for error, especially the welds of safety critical items like tanker bodies. The question is, do you use people to weld or do you get a pricey machine to do it?
Transport Equipment Engineers (TEE) MD, Peter Hoeben says: "We're hoping to move away from steel to 100% aluminium. To achieve this requires both design and fabrication skills. TEE gets its designs from Germany and the USA where they've been well tested. We have an in-house training programme to develop the necessary skills for manufacture with aluminium, like mig and tig welding. We believe in job creation so if we can get a person to do a good job, we'll go that route before we resort to automation."
GRW however, uses an automated aluminium welding process. Says van Eeden: "There's no margin for human error in our operation. Our designs are such that weld integrity becomes critical. Machines give us the necessary consistency and peace of mind."
Full automation is expensive but there are alternatives, a combination of man and machine. American welding machine manufacturer, Lincoln, has a machine that moderates the temperature of the welding material according to the hand actions of the welder. In essence, it supplies an even, steady flow of heat to the material to ensure a strong weld. This sounds like a good insurance policy for the budget conscious aluminium body builder.
A real problem for the trailer and body building industry is the lack of formalised apprenticeships. "Where does a youngster get trained these days?" asks Andre Cilliers, MD, BPW Axles. "The training structures that used to exist no longer do. In-house training is the only option but it's not formalised. The industry needs recognised, accredited technicians coming up through the ranks. We're having to do more with less these days. Sure, machines make that possible but what's an industry without a supply of new blood?"
AFRIT ... Albert van der Wettering
...enough aluminium in the factory to take a
break on. |
Tanker,
TEE |
Semble-It for truckers
A possible solution to the skills predicament could lie in the kit form load body, as manufactured by Hulett-Hydro Extrusions. This technology is still in its infancy but a dropside kit is available and the company is working on designs for other applications. The beauty of these kits is that they require no welding at all and are really simple to put together.
Anita Collins of Hulett-Hydro Extrusions says: "We want to become a one-stop-shop for the truck trailer and body industry. Our all-aluminium designs and products will cover the spectrum of needs as far as the payload section of a vehicle is concerned."
Rethinking design
The question of trailer design is crucial when working in aluminium. According to Tony Paterson of the Aluminium Federation of South Africa (AFSA), aluminium is causing a revolution on the drawing board. "Take flatdecks for example; steel trailers had subframes and plates. Aluminium has turned that design around. We build using extruded floor planks that are themselves the subframe as well."
He explains that tanker designs are changing because of the use of aluminium, "from stress design to ductility design. This is for safety reasons. Where stress design gave you strength, ductility gives elasticity. In the event of a collision, the tanker won't break but will absorb the impact by crumpling. This design will help prevent spills and will also be used in other areas of the rig to improve overall safety in the event of impacts."
Ian Brown, MD, Tanker Trailer Manufacturers (TTM), who has been building aluminium tankers since the early seventies, believes the industry should heed a word of warning about aluminium.
"If you use aluminium, use it correctly," he says. "New European designs worry me. They're not suitable for South Africa. TTM believes firmly in always building tankers with a full length sub-structure. New designs, in the chase for tare, often do away with supporting structures. This compromises safety."
Brown has a single word to sum up his reservations - vibration - which he contends is aluminium's arch enemy. "Aluminium must be allowed to move. It becomes brittle when it work-hardens. If it is exposed to excessive vibration, it will crack." He adds that driving style and air suspension set-up must also be considered when using aluminium trailers.
No turning back
The case for aluminium is a strong one. Steel prices are unstable and look set to rise, while aluminium prices are steady. It may cost more than steel (less than imported alloys like Domex) but it pays for itself over time. South Africa has seen a 73% increase in road freightage over the last ten years and can ill-afford to run overloaded vehicles. Tare mass has to be minimised to allow for greater legal payload. The more each truck can load legally, the less number of wheels will roll over our roads.
As Paterson says: "You get a 10 - 15% payload advantage with aluminium which means every 7th or 8th combination is not needed. This in turn means you don't need the truck, the driver, the fuel, the tyres etc."
If aluminium is up there in the 'dock' and Paterson is its counsel, the transport industry must surely be the jury. Ultimately, the aluminium evangelists need to widen their net and really convince the industry at large that aluminium is tough enough and economically viable to keep the big wheels rolling.
