April 15, 2021

Automotive Industry Embraces Additive Manufacturing

By Nicole Hopper

While it is still a newer technology compared to other manufacturing methods like molding and machining, 3D printing has come a long way in recent years and is becoming more widely accepted across a variety of industries. Just this year, three giants in the automotive world—Porsche, Formula 1, and Ford—all announced new ways they are leveraging the technology.

Additionally, the electric vehicle (EV) sector recently started using an additive approach to inverter design to increase efficiency in production and the components themselves. Across Europe, Audi, Ford, and Alfa Romeo Racing ORLEN have all increased their 3D printing fleets.

Porsche’s 3D-printed electric drive unit housing
Porsche’s 3D-printed electric drive unit housing. Photo courtesy: carscoops.com

Porsche Prints First Complete Electric Drive Housing

Porsche recently built the first complete electric drive unit housing to be fully manufactured through 3D printing. The prototype, containing the engine and gear box, passed quality and stress tests with no issues. Benefits of manufacturing the unit this way meant it was lighter weight with doubled stiffness in highly stressed areas. "This proves that additive manufacturing with all its advantages is also suitable for larger and highly-stressed components in electric sports cars," said Falk Heilfort, project manager in the Powertrain Advance Development department at the Porsche Development Centre.

In general, a key benefit of additive manufacturing is the ability to combine multi-part assemblies into a single piece, in this case reducing assembly work and contributing to an overall higher quality final housing. The integrated parts reduced assembly work by 40 steps, saving about 20 minutes in production per unit.

This isn't Porsche's first investment in the world of additive. The company is also testing 3D printed pistons for its 911 GT2 RS.

Formula 1 Additively Manufactures Engine Block Molds

Formula 1 is exploring a new way to use additive manufacturing to make automotive parts. Rather than 3D printing the parts themselves like Porsche, the international auto racing organization is using printed molds in its engine manufacturing.

Designers created an engine block mold design to be additively manufactured using sand and hardeners. Molten metal is then poured into the printed mold to create the blocks in a process that provides greater precision compared to traditional tooled molds. This technique allows engineers to experiment with different types of sand, glues, and hardeners to control how the aluminum cools in the mold to strategically impact how the final product will turn out.

Ford Puts Recycled 3D Printing Waste to Use in F-250

Ford and HP are partnering to convert recycled 3D printing material into injection molded fuel-line clips for Ford's Super Duty F-250 trucks. In addition to forwarding Ford's sustainability initiatives, the move described as an industry first, actually produces parts with better chemical and moisture resistance that are 7% lighter and 10% cheaper to produce compared to conventional parts molded using fresh material.

Ford's injection molded fuel-line clips made from recycled 3D printing plastics
Ford's injection molded fuel-line clips made from recycled 3D printing plastics. Photo courtesy: Ford

"Many companies are finding great uses for 3D printing technologies, but together with HP, we're the first to find a high-value application for waste powder that likely would have gone to landfill, transforming it into functional and durable auto parts," said Debbie Mielewski, technical fellow at Ford.

The excess material being used to mold the fuel-line clips comes from the HP Multi Jet Fusion printers in use at Ford's Advanced Manufacturing Center to produce other auto parts, as well as well as donated redundant 3D-printing material from businesses like dental company SmileDirectClub. After collecting the material, it is sent to outside manufacturers to turn the waste powders into polymer pellets suitable for injection molding and mold those pellets into the end-use fuel-line clips.

Working to expand the initiative, Ford and HP have found 10 other fuel-line clips on other vehicles suitable for the recycled material molding process and are working on mold designs for those parts next.

Additive Adds Efficiency to EV Production

The UK's newly established Institute for Advanced Automotive Propulsion Systems (IAAPS) at the University of Bath is exploring ways that 3D printing can benefit the production of electric vehicle inverters. A multi-disciplinary research team is working on a project looking at the possibility of 3D printing select inverter components. If successful, additive manufacturing these components would help EV makers overcome constraints including thermal management, electrical noise, and packaging volume.

Concept for the IAAPS’ single piece triangular element in the center of the inverter
Concept for the IAAPS’ single piece triangular element in the center of the inverter. Photo Courtesy: University of Bath

"[SiC (silicon carbide) semiconductor devices] offer so much opportunity to improve inverter performance, but system designers are often unable to take full advantage of their potential because their ideas cannot be manufactured using conventional techniques. Additive manufacturing lets us design in 3D without these constraints, and we see great benefit in applying the technique to EV inverters. These have a significant impact on how hard you can drive other components of the EV powertrain, so even a modest advance can create a virtuous circle of improvements in efficiency, packaging, and energy density for tomorrow's EVs," said Peter Wilson, the professor leading the IAAPS study.

Currently, inverters are designed in a 2D process where flat component boards are stacked with a thick aluminum liquid-cooled cold plate at the bottom. However, the efficiency, reliability, and performance of the inverters drops as temperature rises. The team hopes 3D printing can solve this, as it allows for a complex lattice internal structure with walls less than 1mm thick in the cooling plates, a more effective cooling solution than the plates with machined cooling channels.

The 3D-printed design is also lighter and carries a higher current, making the inverter significantly more power dense. Its more compact assembly means less distance between switches and gate drivers, leading to a more effective Electro-Magnetic Interference. This allows the switches to operate at faster speeds, taking full advantage of the SiC technology compared to the traditional solution.

While this project is still in its early stages in the UK, additive manufacturing in automotive applications is spiking across Europe. In the past three months, Ford became the first carmaker in Europe to add a large format 3D printer to its fleet, Audi began using 3D printing to produce hot form tooling at its Metal 3D Printing Centre, and the Alfa Romeo Racing ORLEN Formula 1 team doubled use of 3D printed parts in its C41 race car. With benefits including lighter weight, more complex, and more complete parts, the shift to additive for auto shows no signs of slowing down.

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