Metals and polymers can also be processed from powders. Densification follows, usually by sintering. There are essentially two basic methods of consolidating powders. Vapor source methods require a vacuum to transport the gaseous source of atoms to the surface for deposition. It generally involves the use of a large force to deform the material.
Many techniques heat the material to reduce the force needed to deform it.
Sometimes a mold is used to define the shape. Forging, an old method that heated a metal and deformed the metal by hammer blows is used today with multi-ton hammers. Rolling to reduce thickness of a plate is another common process. Some glasses when heated can be formed with tools or molds. Machining methods like drilling to make holes or milling are examples of other common deformation processing methods.