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Cold isostatic pressing, CIP

Isostatic pressing of the metal powder by the supply of pressurized fluid to create a green body.

Beskrivning
Illustration of Cold isostatic pressing, CIP

The process

An elastic container [1] is filled with metal powder and placed in a pressure chamber [2]. The container can also be fitted with cores to create more complex shapes.

A liquid at room temperature [3] is pumped into the chamber, creating an evenly distributed pressure along the whole of the elastic container surface. Thanks to the supplied pressure, metal powder particles will be pressed together and mechanically bonded to each other which creates a solid green body. The liquid is removed and the flexible container is allowed to expand and regain its original form, the component can then be removed from the system. 

The currently existing green body is porous and lacks the metallurgical bonds required to obtain the correct mechanical properties. To obtain the desired strength it must be sintered. 

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.

Advantages and disadvantages
In comparison with alternative methods
Uniform density
Suitable for metals
Transfer equal force in all directions to the powder mixture
Allows powder with a low packing density to achieve a sufficiently high density of encapsulation than HIP
Creates a solid preform without binder
Suitable for green bodies with further processing needs
Slower than uniaxial pressing
Components may require post-processing