A Quick Review on Powder Injection Moulding

April 14, 2020

Powder metallurgy is a process where fine powdered materials are pressed into a desired shape or form and then heated or sintered in a controlled atmosphere to form the final product. To date, numerous alternative processes have been deployed under powder metallurgy. One of them is the powder injection moulding process.

What is the origin of powder injection moulding?

The powder injection moulding process is usually recommended for the high-volume production of shaped components out of powder metal. This specific process shares some similarities with polymer injection moulding since they use the same technology. Powder injection moulding is also a by-product of batch sintering processes that are frequently applied in powder metallurgy and ceramic processing.

How does powder injection moulding work?

Powder injection moulding starts with the fusion of polymeric binders with metal or ceramic powders. This specific mixture is heated in a screw-fed barrel and then forced under pressure in a die cavity. The placement of this mixture in a die cavity allows it to cool before ejecting it. Afterward, the polymer will be removed. The sintering of the component to the required density then follows.

The outcome of the debinding stage can directly influence the mechanical properties of the sintered component. Polymer binders, which comprises around 35 to 50 volume percent of the sintered component, must be removed during this stage. If the removal is inconsistent and unsuccessful, then your sintered component may contain swelling, surface blistering, or formation of large pores.

One way to effectively remove polymer is through the multi-component binder system. This system can reduce the percentage of polymers by either removing them with solvents or degrading them at different points of a thermal debinding cycle.

Components shrink during the polymer removal process, but they can still retain the shape of the mould. Nonetheless, your final sintered component can still be made to near-net shape. With powder injection moulding, you can achieve tolerances of 0.2 to 0.3 percent of nominal dimensions and average surface roughness of 15 to 30 micrometres.

What are the benefits of powder injection moulding?

Powder injection moulding is utilised by different industries because of numerous reasons. One, this process can effectively manufacture high-volume complex parts. Another reason is that the production time is significantly reduced compared to casting. Material waste is also minimised with this kind of powder metallurgy process. Powder injection moulding can also readily accommodate a wide range of pre-alloys and master alloys.

Where can powder injection moulding be applied to?

As mentioned, powder injection moulding is suitable for high-volume production of powder metal components. This moulding process can be utilised in making small components. Some applications of powder injection moulding include medical, dental, electronic, firearms, aerospace, jewellery, watchmaking, and automotive sectors. Some examples of products out of this process include silicon carbine turbochargers and radial rotors for heat engines, alumina thread guides, and stainless steel gear wheels for electric toothbrushes.

The popularity of powder injection moulding is increasing because of its effectiveness in producing a huge number of small intricate metal parts. If you want to know more about it, you are free to contact us at PM Distributors Pty Ltd.

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