Sintering is a process in which solid particles are compacted to form a bigger object at high temperatures. This is an ideal process for smaller, complex workpieces with relatively narrow tolerances. It is important to note is that you only achieve approximately 70-85% of the density compared with homogeneous material.
The most common materials are steel, stainless, copper.
The batch size depends on the weight of workpiece, but the minimum is usually 5,000 units.