Almost every industry can take advantage of aluminum’s high strength-to-weight ratio, but the aerospace industry in particular reaps a lot of benefits from any advances in aluminum alloys or processing techniques. Aluminum processing technology is advancing quickly, particularly in the additive manufacturing (AM) field, making new geometries available in lightweight alloys.
What is Additive Manufacturing?
Additive manufacturing (AM) is classified as a group of manufacturing techniques where the material is added layer by layer to construct physical objects. AM encompasses all forms of 3D printing, laser sintering, some thin film deposition techniques, and other such processes.
A robot being used for manufacturing aluminum for an automotive part.
These processes make new shapes possible that cannot easily be cast, assembled, or machined out (subtractive manufacturing). Due to the advancements in this technology, engineers are no longer limited by certain manufacturing techniques. Instead, they can create a part in a computer-aided design (CAD) drawing, send it to a 3D printer, and then pick up a completed part.
The key limitations on AM have been the speed at which parts are produced and the available materials for production. Early AM focused on polymeric materials, which were unsuitable for high-temperature or load-bearing applications. Also, the size of parts produced is a design challenge, as large parts require more post-processing and lots of time to print. The potential for misprinting errors is much higher as well.
The Latest Additive Manufacturing Advancements in Industrial Applications
While plastics have been the lion’s share of AM materials, recent developments have focused on 3D printing metals. Due to the low melting temperature and high strength-to-weight ratio, aluminum alloys have been leading the way in new AM materials.
Aluminum alloys have always been part of the aerospace industry, but are also common in the automotive and automation industries, all of which benefit from custom geometries and low weight.
Boeing upgraded their T408 turbine engine used in the Chinook helicopter. This verification sequence tested the engine’s capabilities on the helicopter and tested a flight-critical 3D printed aluminum gearbox housing. By switching to a 3D-printed part, Boeing was able to save time during design and prototyping. There is a long lead time to produce prototypes and make changes with traditional manufacturing techniques.
A Chinook helicopter testing a flight-critical 3D component. Image used courtesy of Boeing
Boeing is just one of many companies using this AM technology. Optomec is developing 3D printing techniques for electronics and aircraft components. Besides aluminum alloys (7000 series), they also print copper, thermal barrier coatings (ceramic), and various super alloys for turbine repair and manufacturing. They work closely with Sandia National Laboratories, a national laboratory and test facility for many military projects.
Aircraft technology such as turbines are often made from 7000 series aluminum alloys. Image used courtesy of Optomec
ExOne and Ford recently announced a new binder jet 3D printing process for potentially printing engine blocks. Aluminum powder and a binder are printed to form the part. Then the part is sintered to increase its density by removing some of the binder and increasing bonding between aluminum particles. The process has been tested with 6000 series aluminum alloys and has so far been capable of producing fine details in small parts.
The Future of Aluminum AM
Additive manufacturing has expanded rapidly across various industrial sectors over the last decade. Aluminum alloys in particular have been used in many processes due to their strength and durability. There are certain applications where aluminum alloys are the more appropriate selection of material. They are lighter than parts made from steel alloys and often less expensive than composite pieces.
Aluminum is easily recyclable, meaning cradle-to-grave environmental impacts are reduced. Due to this, aluminum alloys will continue to be part of the aerospace industry, and with enhanced AM techniques, they may see even more use in the coming years.
