One of the problems with very strong materials is that they’re hard to work with. Say, for instance, that you wanted to make a brake caliper out of titanium. Until now, that’s been nearly impossible, because milling all of the little channels from a titanium block has been impossible.
Now, though, Bugatti has cracked it. Not literally, of course. Rather than taking a block of titanium or forging it, the French fastest-car-in-the-world makers decided to just 3D print it.
The result is a caliper that weighs just 2.9 kg (6.4 lbs). That’s not exactly nothing, but when you consider first that the calipers (eight-pistons up front and six-pistons out back) are the biggest currently available on any production car, and second that the calipers they’re meant to replace weigh 4.9 kg (10.8 lbs) even though they’re made of aluminum (not exactly a weighty material), the achievement becomes more impressive.
And the result is an extremely strong caliper. The exact brand of titanium used here (Ti6AI4V, in case it helps) is mainly used on the underside of airplane wings and in rocket engines.
As a result, the caliper could support a weight 125 kg (275 lbs) applied to an area just 1 mm squared. So, if for some reason you had a 275 lb drill bit that really had to be stored vertically, look for a Bugatti caliper. Or a rocket engine? Probably best not to, though. NORAD is on pretty high alert these days.
“It was a very moving moment for the team when we held our first titanium brake caliper from the 3-D printer in our hands,” says Frank Götzke, Head of New Technologies in the Technical Development Department of Bugatti. “In terms of volume, this is the largest functional component produced from titanium by additive manufacturing methods. Everyone who looks at the part is surprised at how light it is – despite its large size. Technically, this is an extremely impressive brake caliper, and it also looks great.”
What’s even more surprising is that development of the part didn’t even take very long. From the time someone thought “hmm…” to the time they had a 3D printed caliper in their hands it only took about three months.
Why didn’t this happen sooner? Well, that’s because it’s an extremely time-consuming process. Printing a titanium brake caliper takes about 45 hours, which no one but Bugatti and a select few others have time to wait for.
The process, according to Bugatti, goes like this:
It takes a total of 45 hours to print a brake caliper. During this time, titanium powder is deposited layer by layer. With each layer, the four lasers melt the titanium powder into the shape defined for the brake caliper. The material cools immediately and the brake caliper take shape. The total number of layers required is 2,213. Following the completion of the final layer, the remaining titanium powder which had not melted is removed from the chamber, cleaned and preserved for reuse in a closed loop. What remains in the chamber is a brake caliper complete with supporting structure which maintains its shape until it has received stabilizing heat treatment and reached its final strength.
Heat treatment is carried out in a furnace where the brake caliper is exposed to an initial temperature of 700°C, falling to 100°C in the course of the process, in order to eliminate residual stress and to ensure dimensional stability. Finally, the supporting structures are removed and the component is separated from the tray. In the next production stage, the surface is smoothed in a combined mechanical, physical and chemical process which drastically improves its fatigue strength, i.e. the long-term durability of the component in later vehicle operation. Finally, the contours of functional surfaces, such as the piston contact surfaces or threads, are machined in a five-axis milling machine which takes another 11 hours to complete its work.
The result is a delicately shaped component with wall thicknesses between a minimum of only one millimeter and a maximum of four millimeters.
And since the actual printing had to be done at Laser Zentrum Nord, which mainly works with the aerospace industry, the process likely isn’t cheap either.
Bugatti argues, though—and it isn’t alone—that 3D printed objects are the future of the automotive industry.
“In 3-D printing development, Bugatti is the leader in the Volkswagen group,” Götzke emphasizes. “Everyone can and should benefit from our projects. This is also part of Bugatti’s role as the Group laboratory for high-tech applications.”
For now, though, very intricate, very strong components may help to lighten supercars, the way carbon fiber did for larger parts.
These brakes still aren’t actually on a car. Testing will take place some time in the first half of the year, after which production times will shorten.
The post Bugatti Makes First 3D Printed Titanium Brake Calipers appeared first on VWVortex.
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