Powdered Metal



What is it? 

The greatest advantage to Powdered Metal processes is that the need to use metal removal processes can be avoided, or greatly reduced, thereby drastically reducing yield losses in manufacture often resulting in lower costs. Various parts that can be costly and time consuming to manufacture such as metal gears, or parts that require square holes can be manufactured in less time and are cost efficient if done by a powdered metallurgy process.

The powdered metal process consists of three main steps: powder blending, die compaction, and sintering. After sintering a number of post processes might be pursued, from finish machining, heat treatment, and surface finishing.

Sintering

Sintering is a heat treatment applied to a powder compact in order to impart strength and integrity. The temperature used for sintering is below the melting point of the major constituent of the powder metallurgy material. After compaction, neighboring powder particles are held together by cold welds, which give the compact sufficient “green strength” to be handled. At sintering temperature, diffusion processes cause necks to form and grow at these contact points. 

There are two necessary precursors before this “solid state sintering” mechanism can take place:

  • Removal of the pressing lubricant by evaporation and burning of the vapors.
  • Reduction of the surface oxides from the powder particles in the compact.

These steps and the sintering process itself are generally achieved in a single, continuous furnace by judicious choice and zoning of the furnace atmosphere and by using an appropriate temperature profile throughout the furnace. The process of sintering a metal is very cost effective for parts that can be fabricated using this method. There is virtually no wasted material and the labor content is very low. The one-time tooling cost is moderate but will often produce millions of pieces. 

Sintering offers several advantages: 

  • Very high levels of purity and uniformity in starting materials.
  • Preservation of purity, due to the simpler subsequent fabrication process (fewer steps) that it makes possible.
  • Stabilization of the details of repetitive operations, by control of grain size during the input stages.
  • Absence of binding contract between segregated powder particles – or “inclusions”– as often occurs in melting processes.
  • No deformation needed to produce directional elongation of grains.

Powdered Metal parts offer many advantages:

  • Can produce parts with high-temperature service and extreme durability at lower cost and reduced difficulty
  • Produce parts of controlled, uniform porosity.
  • Can maintain high production rates, for even complex parts
  • Capability to produce nearly net-shaped objects, thus eliminating the need for secondary machining operations
Amfas can provide the best value solutions for any components that are suitable for powdered metal production.

Capabilities 

Part Size

Tiny to 1kg

Materials

Ferrous – iron, steel alloys, copper infiltrated steel, magnetic steel  steel alloys, copper infiltrated steel, magnetic steel 

Non-Ferrous – Brass, bronze, nickel silver, hybrid materials

Stainless – 300 & 400 series

Volume

Prototype to high volume

Equipment Capabilities 

Presses ranging from 45 to 1000 tons

Tolerances by pressing and sintering

± 0.05mm (±.002”)

Applications

  • Automotive powertrains (engine, transmission parts)
  • Engine parts: pulleys, sprockets, hubs, gears, actuators, rings
  • Electric Motors 
  • HVAC Systems
  • Household appliance products
  • Power tools