With even Space X using it to build the body of its new Starship to Mars, Stainless steel is experiencing a revival. While advanced alloys can provide unique yet niche applications, stainless steels like 316L are extremely versatile and – perhaps more importantly – very affordable. That is particularly true if the material is used in a MIM-based filament for such as those supported by Desktop Metal‘s studio system.
That is one of the reasons why the company, which is openly committed to making metal 3D printing more accessible, launched 316L stainless steel for its office-friendly metal 3D printing system for prototyping and low-volume production.
A fully austenitic steel (300-series steels contain nickel to achieve austenite crystalline structure and are not hardenable by heat treatment and essentially non-magnetic), known for its corrosion resistance and excellent mechanical properties at extreme temperatures, 316L is suited for applications in demanding industrial environments, including salt water in marine applications, caustic cleaners found in food processing environments, and chemicals in pharmaceutical manufacturing.
“The addition of 316L enables engineers to print metal parts for a wide range of applications, including engine parts, laboratory equipment, pulp and paper manufacturing, medical devices, chemical and petrochemical processing, kitchen appliances, jewelry and even cryogenic tools and equipment,” said Ric Fulop, CEO and Co-founder of Desktop Metal. “Teams are now able to iterate quickly on 316L prototypes, print complex geometries that are not possible with most manufacturing methods, and produce end-use parts cost-effectively.”
Steeling the scene
Early applications of 316L parts printed with the Studio System confirm the diverse and promising results across multiple industries.
One available case is the production of a combustion fuel nozzle for marine tankers by John Zink Hamworthy Combustion. The UHT Atomizer is a fuel oil atomizer for use with atomizing medium such as steam or air. It is typically installed in an HXG marine burner which is used on steam propulsion boilers on LNG tankers. The objective of the atomizer is to improve low load burner performance, thus allowing the burner to run on a lower fuel oil throughput, saving operational costs when the vessel is maneuvering in port. 316L stainless steel was a key material for the part due to its excellent mechanical properties at high temperatures. Printed with the Studio System, the atomizer can be radically redesigned to function in a more fuel-efficient manner than those produced through traditional metalworking means.
“Unlike many of the parts that John Zink designs and manufactures, this UHT Atomizer can only be fabricated utilizing additive manufacturing. Design constraints of casting, machining and other methods that have bound our thinking for decades can be eliminated as additive manufacturing technology continues to evolve and progress,” said Paul Newman, General Manager at John Zink Hamworthy Combustion, UK.
Another key application case is a customized ring splint for medical use. Ring splints, a common medical device, are designed to immobilize or limit the range of motion of injured limbs. Ring splints are typically made of injection molded plastic in standard sizes and parts often break after a relatively short lifetime. Due to traditional manufacturing methods, finger splints cannot be customized to improve fit. Now, by 3D printing in 316L, ring splints can be custom-printed, on-demand to the desired size, with the added benefit of an aesthetic finish and increased durability.
“Being able to 3D print medical grade steel parts like this finger splint, which is customized to the patient anatomy, offers many advantages as compared to previous fabrication methods that take longer and may have lower efficacy,” said Jim S. Wu, MD, Chief of Musculoskeletal Radiology and Intervention at Beth Israel Deaconess Medical Center, and Associate Professor at Harvard Medical School.
Finally, Desktop Metal demonstrated the use of its new material in the production of an impeller used in harsh environments. Impellers are an essential component of pumps to move fluid through systems. They require complex vanes to optimize pressures in the pump for different fluids and applications. With chemical impellers, 316L is the choice material for its chemical resistance and mechanical properties at extreme temperatures, such as those found in cryogenic, salt water, and petroleum pumps. The impellers are geometrically complex, with prototypes typically costing $1,000 or more to make by traditional formative methods. With the Studio System, this impeller was printed in 316L for $70.
“The oil and gas industry will be a major beneficiary of advances in metal 3D printing,” said Ahmad Khowaiter, Chief Technology Officer of Saudi Aramco. “As the world’s premier energy and chemicals company and an early investor in Desktop Metal we look forward to advancing the state of the art and developing next generation applications where additive manufacturing can leapfrog existing manufacturing methods.”
Steel to come
316L now joins 17-4 PH stainless steel in the Studio System’s materials library. With more than 30 materials in development, Desktop Metal plans to introduce additional core metals to its portfolio throughout 2019, including tool steels, superalloys and copper. “As innovative companies across multiple industries adopt metal 3D printing, its critical to help accelerate this growth by expanding the portfolio of desired materials,” said Fulop. “Our materials science team is pushing the boundaries to enable printing metal parts for a growing range of applications in as wide a material portfolio as possible. The introduction of 316L is another step on our path to fundamentally change the way metal parts are designed and manufactured.”