Freedom by design
Powder metal processes have historically been associated with the production of components for the automotive industry. Growth outside of this sector is accelerating as different industries recognise the benefits of powder metal technologies.
GKN, the world’s leading powder metal manufacturer, has found itself able to drive adoption of powder metal technologies which has lead to a real diversification in its customer base. One such engagement has seen the adoption of Metal-Injection-Moulded (MIM) parts in a medical application. A new artificial limb produced by Otto Bock uses powder metal components, enhancing product performance and reducing manufacturing costs.
The process of Metal Injection Moulding involves injecting powder metal into a hollow mould. The alloy powder behaves much like a liquid, filling the mould in manner similar to classic plastic moulding. The part is subsequently ‘sintered’ in a furnace at high temperatures allowing the part to bind without melting. The resulting part can be highly complex, but produced at a far lower cost than when utilising more traditional methods.
The first challenge is often to educate designers as to the options and freedom that MIM and other powder metal technologies afford. GKN worked with Otto Bock, identifying opportunities with the company’s design engineers. Steffan Sawatzki, head of Prosthetic Knee and Hip Joint Development, still remembers the key benefits “"With the MIM, process designers have more creative freedom, thus entirely new avenues for part design open up [and this results in] chances for product innovation. At the same time compact and sophisticated metal parts design has clear advantages in terms of production costs.” The team were also delighted with the surface finishes that could be achieved, continuing the quality feel of the entire device.
The ‘blocking plate’, ‘blocking hook’ and ‘twin connecting plate’ all manufactured using the MIM process are a crucial part of the knee joint. Amongst other functions they prevent over extension and damage to the joint when in use and allow the ‘knee’ to be bent should a patient wish to sit down.
The freedom that powder metal technologies give design engineers has helped them to develop an artificial limb that gives more freedom to individuals every day.