Pressing is one of key processes of powder metallurgy, which is used to avoid deformations caused in follow-up processes. And its main purpose is to manufacture semi-finished products with devised sizes and shapes. After pressing, the work-pieces after sintering have better strength.
In the process of pressing, powder metallurgy technology is related to the work-piece of organizational change. Pressing will make the contact area increase between particles of powder, the strength increase, and make the porosity of the powder body be reduced. The gathered particles are grinded, and particles of powder are strengthened.
Any infill of particles will cause the increase of particle interface and deformation. The deformation is the reason for the changes of the organization and properties of powder metallurgy. Metal powders are pressed in hydraulic pressing machines or mechanical pressing machines. The main requirements to pressing machines of powder metallurgy are changes of speed, stroke and pressure.
In order to achieve the main advantages of powder metallurgy, both can make products with devised final shapes and sizes, without or with a little machining, detachable pressing mould of powder metallurgy should be used in production