Automotive and racing: where metal 3D printing fits in and where it doesn’t

Automotive is two markets with the same name, and confusing them is the most expensive mistake you can make with additive manufacturing.

In mass production, additive manufacturing is almost never competitive. A part made one hundred thousand times a year involves casting, stamping, or machining, with tooling that has already been amortized and unit costs that powder bed manufacturing will never touch. Anyone who tells you otherwise hasn't done the math.

In competition and in very short series, it pays for itself — and not because of the cost of the part, but because of two things that are worthless in series production: time and weight.

Why in competition, yes

Time is worth more than the part. In a racing team, a redesign that arrives on Thursday for Sunday's race has a value that can't be measured in euros per kilo. Additive manufacturing doesn't require tooling: the file is changed and it's manufactured. That iterative cycle is the real advantage, and it's invisible in any unit cost comparison.

Weight is paid for at every turn. Lightening a moving part—one that rotates, accelerates, and brakes—yields energy back in every cycle throughout its lifespan. This is the mechanism that explains why additive manufacturing can be more sustainable despite using more energy per kilo, and in competition, it translates directly into tenths of a second.

Series range from one to twenty parts. Precisely the range where tooling is not amortized.

The five parts that work

Exhaust and intake manifolds. Pipe geometry with impossible bends, thin walls, and equal lengths between cylinders. Welding a pipe manifold is slow, difficult to repeat, and heavier. It's probably the most recognizable additively manufactured part in racing, and for good reason.

Rudders and turbines. Blades with complex surfaces, often with an integrated housing. Machining them requires five axes and several fixtures; additive manufacturing produces them as a single part. It's one of the best examples of the technology — and one of the parts we have photograph in the sample book.

Topologically optimized supports and tie rods. The textbook case of weight reduction: the load is defined where it should be and where no material can be present, resulting in a shape no designer would draw by hand and no milling machine could manufacture. With the caveat that comes with it: optimizing without criteria produces beautiful parts that fail under fatigue.

Compact Heat Exchangers and Coolers. When a lot of heat needs to be extracted from a small space, additive manufacturing allows for internal surfaces that cannot be assembled in any other way. Here, the alloy is just as important as the geometry.

Spare parts for classic or vintage vehicles. The quieter, and commercially most interesting, case: a part that no one manufactures anymore, without a blueprint, with the mold lost thirty years ago. It's digitized, corrected, and one is manufactured. There's no alternative: it's additive manufacturing or not having the part at all. That's what distributed manufacturing and on-demand spare parts are all about.

What alloy

The full comparison is available at 316L, Inconel 718 or Ti-6Al-4V. And a word of caution: Inconel is sometimes chosen because it sounds high-end, in parts that don't actually experience high temperatures. It's money wasted three times over.

What you need to know before spending

A fatigue-resistant part requires more than just printing. Most of the interesting parts in a racing car are fatigue-resistant, and additive manufacturing is demanding in these cases: orientation changes the outcome, the roughness of the underside is where cracking begins, and internal porosity matters. It's not an impediment, it's a to-do list — anisotropy and orientation and porosity and density.

Lightening is demonstrated, not declared. A topologically optimized part without testing behind it is a sculpture. If the part is for safety, testing is not optional.

Homologation. For street use and many competition categories, there are requirements that depend not on how the part is manufactured, but on what it has to prove. It's best to check this before designing, not after.

When not

• Series of more than a few thousand per year with geometry that can be melted down. No discussion.
• Solid, simple parts. A flat support is laser-cut and bent.
• Large parts. A subframe won't fit, and splitting it destroys the advantage.
• When the only goal is for it to look like a race car. It's a legitimate reason for a showpiece, but it's good to know what that means.

How we approach it

In this sector, useful conversations almost always start the same way: Does this part move, and how much does it weigh today? If it moves and weighs something, then there's a case. If it's stationary and simple, probably not, and we say so.

For an idea of the scale, use the quote calculator. And if you have a specific part that's limiting you—due to weight, deadline, or because it's no longer manufactured—you can bring it in and see it being made during the open days.

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When it's more advantageous to print instead of machining, see print or machine. Parts where it's not worthwhile even if it's possible, see five parts you shouldn't print. And the rules for getting the part right the first time, see design rules for LPBF.