Metal 3D printing moved additive manufacturing out of the prototype lab and put it front and center on the factory floor. Three recent announcements highlight how the industry is finding even better ways to print high-strength and temperature-resistant aluminum objects.
How Metals Are 3D Printed
The technologies these companies work with are different from the filament-based fused deposition modeling (FDM) printers most people are familiar with: powder bed fusion and binder jet printing.
Powder bed fusion printing works by depositing a layer of fine, metallic powder and then melting the particles together with a laser. Some printers use selective laser sintering (SLS) to fuse the powder grains together. The final part will not be completely solid as the sintering process leaves voids between the grains. Selective laser melting (SLM) printers melt the grains completely to create a fully-dense final part.
Binder jet 3D printing works a lot like an inkjet printer. After a layer of metallic powder is laid down on the print bed, the print head sprays a binding agent onto the powder. A sintering process removes the binder and leaves behind the solid metal part. Binder jet printing is fast and price-competitive with forging and casting.
Each of the past week’s announcements addresses different aspects of metal 3D printing to make better aluminum parts
Engineering Better Aluminum Powders
Announcements from Rio Tinto and Amaero as well as from Desktop Metal and Uniformity Labs announcements focus on the new aluminum powders the companies developed. Rio Tinto’s mines in Canada will produce the raw materials needed to create an aluminum-scandium alloy that Amaero will turn into feedstock for its SLS and SLM printers.
“Aluminium-scandium alloy is the material of choice where a lightweight, high-strength material with thermal resistance and good welding properties is needed, such as for defence and aerospace applications,” said Rio Tinto Aluminium vice president Sales and Marketing Tolga Egrilmezer.
Desktop Metal and Uniformity Labs created a new powdered aluminum that lets companies print parts from 6061 aluminum, one of the most-commonly-used aluminum alloys. Since the powder does not require additives, the final part has better yield and ultimate tensile strength than parts made from wrought 6061 aluminum.
“These are the best reported properties we are aware of for a sintered 6061 aluminum powder,” said Desktop Metal CEO Ric Fulop. Uniformity Labs CEO Adam Hopkins added, “The introduction of lightweight metals to binder jetting opens the door to a wide variety of thermal and structural applications across industries.”
Building Better Metal Printers
An announcement from Ford Motor Company and ExOne focuses on a new binder jet printing process for sintered aluminum parts that have 99% of the density and physical properties of traditionally-manufactured parts.
Ford technical leader for additive manufacturing Harold Sears said, “This is a breakthrough in making 3D printed and sintered parts for the auto industry. High-speed aluminum 3D printing paves the way for other opportunities that we’re just now starting to take a look at because of the ability to do complex parts with aluminum that previously weren’t possible.”
Enabling New Aluminum Applications
The new aluminum powders and 3D printers announced this week will let manufacturers produce aluminum parts with geometries that were never possible before. As ExOne CEO John Hartner explained, “Developing a fast, affordable, and easy way to 3D print aluminum with traditional material properties is a critical step toward light-weighting more products and delivering a more sustainable future.”
