What does 1kg cost your company? Engineering experts explain how their companies and research teams are prioritising light-weighting technologies to save money and improve performance.
[Panel debate at Subcon 2012, Twitter @SubconShow]
Stripping weight out of products while maintaining structural strength is a fundamental principle of engineering. As prices of materials rise and competition for better performance increases, lightweighting in engineering manufacturing is more important than ever.
Dai Jones, Architecture Leader at Jaguar Land Rover told the Subcon audience that lightweighting is fundamental to the carmaker’s work. “If we save 200 kg off the body, the weight loss spiral continues. You can then downsize other parts.”
The “holy trinity for aircraft” is weight, aerodynamics and proportion, said Colin Sirett, Airbus’s head of research and technology. “Weight has a value to the airline operators. Think of saving 1kg on an aircraft – that could generate $1m in revenue to the operator for the life of the aircraft. A solution that saves 200kg has serious cost-saving implications.”
About 52% of Airbus aircraft are made using composite materials, the primary driver being lightweighting. There are some limits to how much more could be “compositised”, says Mr Sirett. “Titanium, while very expensive, is a very good metal to use at the interface with composite materials. This, and its strength, makes the titanium composition of aircraft – currently about 14% – hard to reduce further.”
Patrick Wood, director, head of engineering & industrial operations at Astrium Satellites said “For every 1kg we save that equates to $10,000 on the satellite launch cost. The operating environment is very challenging. How do you qualify the materials to be used is very challenging which makes weight reduction difficult.”
Transport costs are also part of the total cost. Astrium recently shipped 20 tonnes of equipment to a launch site in Iceland, “in the middle of nowhere”.
A commitment to lightweighting might demand a step change in manufacturing processes, form subtractive, machine and cutting-based manufacturing – the mainstay of events like Subcon – to additive manufacturing.
Jaguar Land Rover is committed to both techniques. “We look at the different performance of material through pressings and simulations,” said Dai Jones. “You’re developing thinner and thinner walls in castings as long as this table; we call it “wringing the flannel dry” to take weight out wherever practical. Our pareto analysis reveals where weight can be removed and we are getting 3mm-4mm castings now.”
On a car that is made from composite panels or even one “printed in plastic”, Mr Jones said the consumer perception is central. “There is a mindset about the plastic car. As we imagine the world of the plastic car, it gives people the impression it’s not safe. But the aerospace sector is showing that it’s very safe.”
Prof Richard Hague, director of the EPSRC Centre for Innovative Manufacturing in Additive Manufacturing (AM), admitted the near-term application of additive manufacturing in mass automotive manufacturing was small. “But for titanium linkages for carbon parts and titanium parts in general, AM has a huge part to play.”
The material was proven, Hague said, but the manufacturing process needs more validation. “Today it’s about the design tools and the process and materials all in one go. You can be effectively producing new materials at the point of manufacture, not machining from a block. That won’t be practicable for automotive, for example, now, but will in 15-20 years.”
The challenge inn space is the qualification of the material, says Astrium’s Patrick Wood. “In the space industry we build something specifically to test it, after which we are more likely to actually build the satellite,” suggesting there are lots of opportunities to build AM prototypes. “The UK Space Agency creates space missions that allow you to fly new technology, providing excellent opportunities to get real life data. This allows us to make terrific models with AM.”
Sanctioning those complex structures manufactured using AM for space flight is the difficult part.
MORE on this subject from Airbus, Astrium and others will follow shortly
