The method can be performed without automation, but usually it’s automated as it’s suitable for this.
[A] A constantly filled powder fill shoe [1] is positioned on top of the pressing die [2], which is filled with metal powder. At the bottom of pressing die there is a punch [3], which is lowered to its lower position.
[B] An upper punch [4] is lowered and both punches then move towards each other to compress the powder with applied pressing force.
[C] The upper punch is removed while the lower punch pushes the part up to the surface to be easily removed.
[D] The powder feeder positioned back on top of the pressing die and pressed into a part and the process is repeated.
The compression of the powder results in a green body [5] in which the metal particles are mechanically bonded to each other. This detail is fragile and does not have the final properties needed. The punches themselves can be divided into different section to be able to reach different densities in the green body’s different parts.
To convert the green body into a useful component, it must be subjected to heating, by diffusion its atoms will have the desired metallurgical bond required to have high strength. This post treatment called sintering and is carried out in a sintering furnace filled with an inert gas to prevent any reaction with oxygen.
To further enhance and customize the component to the desired end form, common secondary operations such as restamping, Carburization, infiltration, impregnation, surface compression are done. The component may also undergo repeated sintering to increase its density.
Often done along with conventional processing methods such as milling, turning and grinding.
