Technology is moving at a breakneck pace and one area that has transformed the motoring industry is the development and use of 3D printing.
But we would be mistaken to think that this innovative technology is a new initiative because it has been used by Jaguar Land Rover technicians for more than 20 years with the company plugging millions of pounds into its research and development.
During a behind-the-scenes look at the technology, Mark Barrington, manager for rapid prototype and tooling at JLR, somehow made the incredible complicated systems seem almost simple – almost!
JLR currently utilises 10 machines, including four 3D processors costing about half a million pounds each. These machines can be found at JLR’s Gaydon and Whitley sites and they run 24 hours a day, seven days a week and this year alone will produce more than 50,000 components that will be used in prototype models.
So to help us understand the concept of 3D printing, Mark explained, “We take an engineer’s Computer Assisted Design (CAD) data which is sent here to the 3D print shop. We analyse it, cut lots of slices through it at 0.1mm and create a 3D contour map of the shape of that part. If I then print out each of those shapes on a piece of paper, get some scissors and cut all of those shapes out and glue them together I would create a cardboard model of that component and that’s how 3D printing works.”
But obviously the criteria for each part may differ. For example some components need to be brittle, others flexible and some may have moving parts or different surfaces – to overcome the issue there is a machine for all purposes.
In theory, there are four types of 3D technologies – Stereolithography, Laser Sintering, Fused Deposition Modelling and Polyjet Modelling.
The original 3D printing processor invented back in the 1980s is called stereolithography and this works in conjunction with a vat of resin. When it is exposed to ultra violet light it solidifies.
Mark commented, “Inside the vat of resin is a platform that moves up and down like a table. It has lots of holes in it so it can move through the resin without disturbing it too much. But the process starts with that platform lifted up to a point just beneath the surface of the liquid.
“Inside the machine is an ultra violet laser and it points at a mirror. I can move that mirror with great precision and direct the laser light so that it moves around on the surface of the liquid. Everywhere the laser light touches the liquid it turns liquid into solid.
“So I start with a very thin 0.1mm layer of liquid above the platform – I take the first slice from the CAD data and with a laser I draw it on the surface of the liquid. Everywhere the laser light goes it solidifies the liquid, so I draw the slice, fill it in and I have created this whole region of material that is solid.
“Then I lower the platform for the next slice which bonds itself to the first slice. The second line of data is added and I keep repeating the process every 0.1mm. So to build a part that is 500mm high might take quite a bit of time.
“There are two spot sizes. To draw profile uses a very small spot but filling in uses a thicker spot.
“Parts come out the machine and have to be washed and given an extra dose of UV light to finally cure them.”
However there is a problem with parts created within this machine as they are very brittle and would break if dropped. So in reality these components might be found in a static concept car where they look totally realistic.
The second option is called Polyjet Modelling which works similarly to an ink jet printer except it uses photopolymers (a polymer that changes its properties when exposed to light)instead of ink. Once again it is cured by the UV light, but this time the print head moves across the platform and dispenses little droplets of photopolymers. A UV light is attached to the print head and almost instantaneously cures the photopolymers as it is jetting.
This technology is ingenious and has huge benefits as Mark explained: “The really clever thing about this machine is that I can print with more than one material. The white material is pretty rigid and a little brittle. But I can also print with a flexible material, so we can combine materials to make parts like an air vent.
“It works with thinner layers too so we can get quite extraordinary detail. In fact, we can print a working mechanism as one part.”
As the object builds layer by layer support pillars are incorporated and these will be manually brushed away in the clean-up area.
Five of JLR’s 10 industrial 3D printers are Laser Sintering machines which is the third method whereby a powdered nylon is used rather than liquid.
Once again the component is created in layers on a moveable platform inside the machine where temperatures reach up a blistering 180 degrees centigrade.
Mark said, “The laser in this machine generates heat and light and is directed onto the powder. Everywhere the laser goes, the powder melts. I create a region of material that’s bonded together. I lower the platform and lay down a new layer of powder, heat it up and the laser draws the next slice.
“The end result is a big block of powder, inside of which I’ve printed some parts. I can print as many parts as I can fit in the block of powder.”
Then it’s time for the cooling process to take place which can take between 28 and 48 hours depending on its size.
This type of machine can produce an audio speaker unit in the very finest detail.
The final process is called Fused Deposition Modelling and is fascinating to watch as a nozzle moves around and draws the slices, laying down a bead of liquid plastic material as it goes. It draws the outline of the shape, fills it in and then the platform is lowered slightly and it draws the second layer. It uses standard thermoplastic materials that would be used in a car.
Mark (below) explained, “Once again we build in layers and this technology also needs supports as it builds upwards slice by slice. When it’s finished we soak it in hot water with some detergent to get the support material away and it melts away.
“It’s our largest machine – we could build a part as big as 900x600x900mms.However, if we built something that big it would be quite a slow process.”
Mark works with a team of 110 people to produce prototype models and with 10 in the 3D printing department and whilst at present no 3D printed parts are ever used in customer vehicles because it’s still an expensive process, it is likely to become integrated into the development process more and more as time goes on.
Mark said, “I think mainstream automotive will continue to use these techniques for prototyping primarily for the next five to 10 years and progressively we’ll see opportunities to 3D print parts and put them into initially low-volume, high-value cars.”
And the real beauty of 3D printing has to be the tweaking stage as Mark explained. “If we print a part and then need to make alterations it’s very easy. We just go back to the CAD data and make the necessary adjustments and then print another one.”
Maxine Ashford is editor of
Maxine has more than 30 years’ experience in journalism and has been specialising in motoring for the last 18 years, so fulfilling a life-long passion. It gives her the chance to drive all the new models both here in the UK and overseas, as well as interviewing the specialists and engineers behind the very latest innovative technology. Maxine has written for national and regional newspapers, specialist magazines, leading websites and also completed assignments in broadcasting.
