One of the most common aftermarket parts people purchase for their cars is a new set of wheels. A fresh set can really change the look of a car, while at the same time offer surprisingly large performance benefits. Some of the finest aftermarket wheels in the world come from HRE Performance Wheels. The San Diego-based company makes high performance wheels that are both lightweight and strong, while also giving their clients’ vehicles a unique look.
While most of HRE’s products are forged one- or three-piece wheels, they’ve been on the cutting edge of wheel production technology. One of their most recent accomplishments is the creation of the first ever 3D-printed titanium wheel, the HRE3D+, and it has the potential to completely disrupt the way we think about wheel manufacturing. To do this, they partnered with GE Additive’s AddWorks team to help develop the processes and schemes to create designs the world has never seen before.
To understand why 3D-printed wheels are such a game changer, it’s important to understand how high performance wheels are currently made. Almost all wheels currently are either cast or forged. Cast wheels are made by pouring liquid aluminum alloy into a mold and letting it cool into the shape of the wheel. Forged wheels like the ones sold by HRE are created by taking a single block of aluminum which is then heated and pressurized by machines into the shape of a wheel. The wheel is then spun into the wheel’s barrel like a clay pot with more heat and pressure, before the interior and the face are cut out with a lathe. The wheel is then polished and finished before being sent off to the customer.
The forging process creates a much stronger and lighter wheel, but a set of forged wheels can cost almost three times as much as a set of cast ones. It’s an intensive process that requires a lot of manual labor and technical know-how to pull off. The designs are also limited by the geometry of the lathes and other machines used in the process. Additionally, the use of more advanced materials like titanium is very difficult due to the requirements involved with machining those advanced metals.
Utilizing the new technology of 3D-printing flips many of the wheel building conventions on its head. Instead of taking a 100-pound chunk of aluminum and machining it into a 20-pound wheel, the process developed by HRE and GE Additive builds the wheel from the ground up using a fine titanium powder. Referred to as Electron Beam Melting, the process melts a bed of powder on top of a build plate with thermal supports, layer by layer, to create the part seemingly out of thin air.
The HRE3D+ was produced by using two different GE Electron Beam Melting machines to make five separate parts of the spokes. Each part was then brought together by a custom center hub, before being bolted to a high-tech carbon fiber rim with titanium bolts. While the whole wheel was not built out of titanium, the spokes that provide all of the strength were. HRE and GE do say that the process has allowed them to explore greater uses of titanium in the future, while changing the way they think about both 3D-Printing and wheel construction.
While still a cutting edge advanced technology, the additive process has a variety of benefits that could trickle down into more standard wheels. For one, Electron Beam Melting allows for the use of advanced titanium alloys that would otherwise be too difficult to work with through standard manufacturing techniques. Titanium is much lighter and stronger than aluminum, making it ideal for use in a wheel. A lighter wheel allows a car to go faster due to less unsprung weight and rotational inertia, and titanium’s greater strength allows it to withstand much greater forces and loads, especially in high performance applications.
Additionally, the technique used by HRE and GE Additive allows for wheel designs that have never been a possibility. The HRE3D+ showcases this by utilizing spokes that are interlaced with each other, as well as hollow areas and multiple parts that come together to create a single wheel. The result is a fantastic looking wheel that is unbelievably intricate and unlike anything that has ever been seen on a wheel before.
The process is also much more efficient. The standard method of forging typically ends up removing 80% of the material originally present in the aluminum block that serves as the basis of the wheels. While that material is recycled by HRE and turned into other products, it is still a waste of metal that requires extra time and energy to remove. With Electron Beam Melting, only 5% of the material is removed over the course of the process, and that waste can theoretically reused in the next wheel produced.
Best of all, the use of 3D-printing has the potential to reduce the cost of wheels in the future. As the process is more efficient, less material is needed to make the product, and less hours are required to shape the material into its final form.
The HRE3D+ may only be a prototype, but it shows off a technology with a lot of potential. The lessons learned from this exercise should trickle down into more normal applications that could be beneficial to even the most normal cars. You may not be able to order a set of titanium 3D-printed wheels today, but it’s not completely out of the question that we may see them available in the next several years. The work done on this project is completely ground breaking, and it’s guaranteed we will see its results in the future.
Image Credit: HRE