Many manufacturing industries depend on the mass supply of metal parts to run their systems and processes at optimum speed and produce high-impact consumer products. Old metal working methods like forging and casting failed to keep pace with the evolving demands for several reasons, including expensive manufacturing costs, limited options of materials, lack of uniformity in shapes and finishing of the final products, etc. These repeated challenges compelled the metalworking industry to take an innovative approach and find something to simultaneously address all the significant concerns. Finally, it led them to an advanced metalworking technique where they could use metal powder to make even complex designs with perfection.
Powder metallurgy is the technology being hinted at here. Although the upfront manufacturing cost is high, its resourcefulness and ability to control industrial wastage compensate for most other areas. Let’s understand this process a little.
- Powder Metallurgy
Powder metallurgy (PM) has emerged as an excellent alternative to casting and machining processes. Many credit its high predictability for successfully creating parts that other competing manufacturing systems fail to emulate. Even if they succeed, the products become too expensive. Hence, different industries support the new metalworking technique that helps them obtain endless geometric shapes and sizes required for high-volume manufacturing. The part-to-part uniformity and precise tolerance levels make this process more dependable. How does it achieve the results? It begins with material selection and blending. Choices include steel, copper, bronze, aluminum, iron, etc. All these are blended with lubricants to build a desired part for a specific application. After this, the powder mixture is placed into a die for compaction. Compaction helps obtain green parts that mimic the size and shape of the end product when released from the die.
However, these parts need to be stronger, which leads to the next manufacturing cycle called sintering. Green parts are fed to the furnace for heating. The inside temperature is kept lower than the melting point, enabling metal particles to bond well. Eventually, those powder metallurgy parts are sent for optional secondary operations to increase their strength, endurance, density, corrosion resistance, performance, and shape. Secondary operation types include oil or resin impregnation, coatings/ plating, steaming, grinding, and sizing.
- Materials used in powder metallurgical processes
Stainless steel is one of the common materials used for manufacturing PM components. PM manufacturers press and sinter stainless powder or apply metal injection molded technique to finish the products, such as sintered filters. Copper alloys are used in structural parts. For example, the bronze powder obtained after processing copper and other elements is compressed into self-lubricating bearings and sintered filters. Iron is also a popular choice in powder production. Iron can be mixed with nickel or chromium to create consistent microstructures. Anything built with iron and nickel mixture is preferred for its superior corrosion resistance.
In summary, the metalworking field drastically changed after the adoption of PM manufacturing techniques. Although this specific process has also been around for many years, it caught everyone’s attention when industries like automotive witnessed sudden growth and evolution, generating massive demand for different metal parts. At that time, PM technology rose and started scaling to satisfy their production goals.