WOLVERHAMPTON'S SECRET .. and ADDITIVE MANUFACTURING IN ACTION
Tony Cotton visited Wolverhampton University's Engineering Faculty,
at their Telford Innovation Campus, to see their Monoposto car, and enthuses
over their equipment.
The courses relevant to this article are Automotive Engineering (which includes Formula Student) and Motorsport Engineering, which involves the Renault. The intention is not necessarily to produce the next Adrian Newey (though that would be nice..) but to use the subject to inspire the students to become well rounded, innovative, practical engineers who can join a range of engineering businesses and contribute to their success. Theory is dealt with by courses in mathematics, thermodynamics and liquid mechanics. Solid modelling (3D CAD), finite element analysis and computational fluid dynamics are part of the course too, with the car being used to show the practical side, and to correlate what's expected with what happens in reality. Hands on experience also gives an understanding of working with the results of the theory and of handling spanners, nuts and bolts and getting as frustrated as the average racer does at the multiplicty of Metric, UNF, BSF, and other fasteners. For some universities, an engineer who can tighten a nut would be a novelty. It's also a good thing for people involved in engineering, whether motorsport or some other field, to be able to understand that whilst motor racing seems glamourous when you're watching the Monaco GP on TV it can be a bit less so when getting up at 4.30 to drive to testing at a cold and wet Snetterton.
After talking about the course, I got to see the toys. Or should I say laboratory equipment. Naturally, there's the standard metrology stuff for measuring, and presses and test machines. “We've got kit to break virtually anything” said Dave with a smile. Of more interest to motorsport enthusiasts is a four-poster rig on which suspension can be optimised, and a couple of engine dynamometers (the electric rather than water type) on which it's possible to test and measure road and race engines. Various other labs for pneumatics, electronics and a composites shop make the place the envy of most professional F3 teams, let alone Monoposto. They heard the day before my visit that a wind tunnel had been offered from an F1 team. They already have an open wind tunnel. However, I've kept what for me is the best, until last.
3D printing / rapid prototyping is no longer a novel process. They have a machine which can, for example, print a set of meshing plastic gears enclosed in a plate using the principle of adding plastic layer by layer from a nozzle. But even more exciting was the Direct Metal Laser Sintering equipment. Wolverhampton University is currently using it to produce items in Titanium, Aluminium, Steel, Nickel Chrome Alloys, Bronze, Copper and Silver Alloys.. The process is a combination of startling simplicity and the sort of technology which was science fiction when I was a child. It starts with a very fine layer of powdered metal – – it can be as thin as a quarter of the diameter of a human hair (0.020mm) – which is spread on the surface of the machine bed. . A laser, carried to the head of the machine through fibre optics and put through a lens to ensure its purity, is then directed by mirror onto the surface where, as it is switched on and off, it selectively fuses the powder. Hence sintering. It's effectively welding one layer to the previous one. The unfused powder is then blown off, filtered and reused with a waste rate of around 5% and the process repeated. The machine isn't fast, depositing around 7cc in an hour, against 70 or 80 times this speed for starting with a billet and machining it away. Professor Mark Stanford, who is in charge of this department, explained that whilst the machinery can make solid objects, that's often a waste of its capabilities. He told me “The makers of our equipment describe the process as “manufacturing led design”. You have to forget what you know about what's possible. I like to say that “the complex geometry come for free”, by which I mean that if you are starting with a solid piece of metal and traditionally machining it away, it costs more the more metal you remove. Some shapes are too complex to machine from solid, and some are just impossible. But with additive manufacturing, you're effectively taking slices through a CAD drawing and making them. And just paying for the material you can see in the end product. The worst thing you could ask me to make is a solid block.”
To illustrate the merits of the process he showed me a demonstration with a simple block, one hole in the top for a fluid to go in, 2 on the side where it comes out. To machine it from solid you would bore it down, then across to split the flow, cap off the ends, and then bore into the cross bore. You're left with sharp corners and a heavy piece. The additive manufacturing solution starts with designing the ideal flow (using CFD) and then working out the lightest way to support the pressure (a thin wall with a network around it in this example) and then, to get the strength of the solid block, use finite element analysis to decide where to put the supports from the top to the bottom of the block. The result is a lightweight part, which functions better. If it's made of an expensive metal, there are significant savings in material cost (though not machine costs) because the only material used (apart from very slight waste) is what ends up in the final product. 2 real life example were then shown, a part which contained a labyrinth of 64 tiny air passages. Impossible to make any other way, the university has succeeded in reducing its size without affecting the function. In fact, such is their experience in this area that they are a supplier to one of the F1 teams where they are recognised as having an expertise the team hasn't got internally. And in return, they bring funds to the faculty. Turnround times are very tight, in some cases only a few days from receipt of the CAD file to delivery. The other example I saw was a part requiring internal cooling. Made by the additive process, it's possible to not only get the coolant exactly where it's required, round all manner of corners, but to also include tiny radiators which look like a high precision Shreddie. And if that isn't enough, the material properties can be subverted. By leaving tiny, tiny areas unwelded by the laser, a part can be made to selectively bend easily whilst having an overall integrity. Additive manufacturing is obviously a technology in its youth, but one we'll be seeing a lot of in the future. And perhaps even in the Mono paddock.
I would like to take this opportunity to thank Dave Tucker and his colleagues at Wolverhampton University, Mark Stanford and Mike Basini, for their time and patience with a disruptive old Mono racer showing schoolboy enthusiasm while going around this engineering centre of excellence of which I'm sure we'll hear more.
ps lest any other teams think we've given too much space to Wolverhampton - write a piece for us!
Disclaimer: The above represents only the unofficial view of the writer and not of the Monoposto Racing Club in any way whatsover. Subheadlines and captions are not originated from the named author. We are unable to reproduce results due to copyright reasons. If any pictures are copyright and the owner wishes them removed please email us.
The Wolverhampton University Telford Innovation Campus
A selection of the machining equipment
Rapid prototype bone
Eosint M270 laser sintering machine can even handle steel
In the top left hand corner the laser is fusing the (in this case silver) powder to form a component about the size of a finger nail.