Technical Resources

Knowledge Base & FAQ

Explore common questions about Powder Metallurgy and a comprehensive glossary of industry terms to help you make informed engineering decisions.

Frequently Asked Questions (FAQ)

Q1: Is the strength of Powder Metallurgy parts sufficient for high-load applications?

Absolutely. While PM parts have inherent micro-porosity, their strength can be engineered to meet or exceed that of cast iron or even forged steel. By adjusting alloy compositions, increasing compacting density, or using Secondary Forging, PM parts are now widely used in high-stress environments like automotive engines, transmission gears, and connecting rods.

Q2: Which is more cost-effective: Powder Metallurgy or CNC Machining?

It depends on the production volume. CNC Machining is better for low-volume prototyping because it doesn't require expensive tooling. However, for mass production (typically 5,000+ units), Powder Metallurgy is significantly cheaper. PM reduces costs by minimizing material waste (Near-Net Shape) and eliminating the labor-intensive steps of traditional cutting.

Q3: What materials can be used in the PM process?

PM is incredibly versatile. It can process almost all metals, including:

Ferrous Alloys: Iron and steel (most common).
Non-Ferrous: Copper, aluminum, and brass.
Refractory Metals: Tungsten and Molybdenum (which are difficult to melt).
Specialty Materials: Stainless steel and superalloys for aerospace and medical use.

Q4: Why is Powder Metallurgy considered a "Green" technology?

PM is one of the most sustainable manufacturing methods. It boasts a material utilization rate of over 95%, meaning almost no scrap metal is produced. Additionally, because the sintering process occurs below the melting point, it often requires less energy than traditional melting and casting operations.

Q5: How do "Self-Lubricating" bearings work in Powder Metallurgy?

This is a unique advantage of PM. Because the parts are naturally porous, they can be vacuum-impregnated with oil. When the bearing heats up during operation, the oil expands and flows to the surface. When it cools down, the oil is re-absorbed into the pores by capillary action. This makes them ideal for "maintenance-free" applications.

Q6: What is the difference between traditional PM and Metal Injection Molding (MIM)?

While both use metal powders:

Traditional PM is like "pressing a tablet." It is best for larger, simpler shapes.
MIM involves mixing powder with a plastic binder to "inject" it into a mold. It is designed for extremely small, highly complex parts (like those in smartphones or surgical tools) that would be impossible to press.

Q7: Can PM parts be plated or welded?

Yes, but they require preparation. Due to the porosity, PM parts are usually steam-treated or resin-sealed before plating to prevent chemicals from getting trapped in the pores. For welding, laser welding is preferred to minimize the heat-affected zone.

Q8: What are the design limitations for PM parts?

Engineers should avoid features that prevent the part from being ejected from the die. This includes:

Side Undercuts: Holes or grooves on the side must be machined later.
Wall Thickness: Walls should generally be thicker than 1.5mm to ensure even powder flow.
Sharp Corners: Rounded edges (fillets) are preferred to extend tool life and improve strength.

Powder Metallurgy Glossary

Term	Definition
Gerotor	Short for "Generated Rotor". A positive displacement pumping unit consisting of an inner and outer rotor. PM is the most efficient method for manufacturing these complex trochoidal shapes used in oil pumps.
Green Strength	The mechanical strength of a compact before sintering. It must be high enough to handle transportation to the furnace without breaking.
Sintered Density	The mass per unit volume of a part after sintering. This is the primary indicator of the part's final mechanical properties.
Diffusion Bonding	The process where atoms migrate across particle boundaries due to heat, fusing the metal particles into a solid mass.
Near-Net Shape	A manufacturing technique where the initial part is created very close to its final geometry, reducing the need for secondary machining.
Oil Impregnation	The process of filling the interconnected pores of a sintered part with lubricant, typically used to create self-lubricating bearings.
Metal Injection Molding (MIM)	A process where fine metal powder is mixed with a binder and "injected" into a mold. Best for small, extremely complex 3D shapes.
Steam Treatment	A process that creates a layer of black iron oxide (Fe3O4) on the surface to improve wear resistance and provide a decorative finish.
Infiltration	Filling the pores of a sintered part with a lower-melting-point metal (e.g., copper into an iron part) to increase strength and density.
Porosity	The volume of pores (voids) expressed as a percentage of the total volume. It can be "open" (connected) or "closed" (isolated).
Debinding	The critical step (especially in MIM) of removing the polymer or wax binders from the part before the final sintering stage.
Reduced Powder	Metal powder produced by chemical reduction of an oxide. These particles are usually spongy and irregular, providing good green strength.
Sizing / Coining	A secondary pressing operation used to improve the dimensional accuracy of a sintered part or to increase its surface density.
Segregation	An undesirable effect where different powder particles separate during mixing or feeding due to differences in size or density.
Spherical Powder	Powder particles produced by gas atomization that are perfectly round. They offer excellent flowability for 3D printing and MIM.
Isostatic Pressing	Applying pressure from all directions using a fluid (water or gas) to achieve uniform density in large or complex shapes.
Apparent Density	The weight of a unit volume of loose powder. It is crucial for determining the "fill depth" of the die during the compacting stage.