(1) Mixing: Fine metal powder, thermoplastic and paraffin wax binder are mixed in precise proportions. It is mixed in a special mixing equipment and heated to a certain temperature to melt the binder. In most cases, mechanical mixing is used until the metal powder particles are evenly coated with a binder and cooled to form a granular raw material.

 

 

 

 

 

(2) Molding: The equipment and technology of injection molding are similar to those of injection molding. The raw materials are fed into the machine to be heated and injected into the mold cavity under high pressure. This link is formed (greenpart) and demoulded after cooling. Only when the binder is melted (fully fused with the metal powder) at a temperature of about 200°C, the whole process can be carried out. The cavity size design should consider the shrinkage produced during the sintering process of the metal parts.

 

 

 

 

(3) Degreasing: Use physical or chemical methods to remove the binder from the parts, the most commonly used is solvent extraction. Most of the binder is removed before sintering, and the remaining part can support the component to enter the sintering furnace and be volatilized during sintering. The parts change from a mixture of metal powder and binder to pure metal parts, the volume shrinks, and the shape and structure remain unchanged.

 

 

 

 

(4) Sintering: The parts are put into a furnace controlled by high temperature and high pressure. The part is slowly heated under the protection of gas to remove residual adhesive. After that, the part is heated to a very high temperature, and the voids between the particles disappear due to the fusion of the particles. The part shrinks to its designed size and transforms into a dense solid, the volume shrinks further, and the shape and structure remain unchanged.