Attention to detail: the advantages of metal binder jetting technology
The Höganäs-owned company Digital Metal combines the benefits of binder jetting technology with Höganäs’s expertise in metal powders and sintering processes to create a world-class system for 3D metal printing with exceptional accuracy and repeatability.
The Digital Metal system works by building parts layer by layer, applying a binder to each layer of metal powder inside a print box. No supports are needed since no melting takes place during the process, and the surrounding powder inside the box provides enough support for the parts. Once completed, all loose powder is removed and reused, thus minimizing waste to virtually zero. The printed parts are then sent to a sintering furnace to gain density and the required material properties. Because the printing and heat treatment are separate processes, each can be optimized according to the specific material being used.
“Our technology gives us very precise control of the whole process, which is important because every step affects the quality of the final product,” says Alexander Sakratidis, Sales and Marketing Manager, Digital Metal. “All the moving parts inside the printer have very precise movements and an accuracy down to single microns.”
This enables Digital Metal to produce parts and components of up to 150 millimeters in size with highly detailed and complex designs. Currently, its technology is being used by customers in the medical, automotive, aerospace, dental, luxury goods and energy sectors. Components can be printed with a resolution of 35 microns, with walls as thin as 0.2 mm and holes down to 0.2 mm in diameter. The process can also achieve a surface roughness averaging six microns without any post-processing.
Temperature precision is essential
Digital Metal’s high level of accuracy allows for repeatability and the capacity to serial-produce to scale. Good control of sintering, as the final step in the process, is important to ensure consistent quality in the final output. However, different metals require different temperatures, so precise temperature control is vital.
“You cannot use just any furnace,” Sakratidis says. “To get the best result and desired material properties you need to apply a certain temperature profile/cycle during sintering. This will give the finished component the optimal density and correct size. If you do not have tight control of the sintering temperatures, you will see poor results in the finished product.”
Digital Metal’s binder jetting system can achieve a much higher level of productivity compared with a laser-based system. “It takes the same amount of time to print one part as it does to print 1,000 at the same level, whereas with a laser-based system, each part is printed individually, so the more components, the longer time it takes,” Sakratidis explains.
Being wholly owned by the world’s leading metal powder manufacturer is also hugely beneficial to the process, particularly when it comes to material knowledge and sintering.
“Höganäs has been working with metal powders since the 1940s,” Sakratidis says. “It has accumulated a lot of experience and expertise when it comes to binder composition and sintering and how they can be combined to achieve the best results in finished products.”