Features favoring PM

1
Features favoring PM

• Small Size
• Geometry
• - Flat surfaces with few thicknesses
• - Straight side walls (constant
  cross-section)
• - surface finish and precision
• High volume production
• Production without secondary machining
  associated production of scrap
• Impregnated oil components

2
Alternative processes

• Precision casting
• Finish machining of forged preforms
• Finish machining from sized rods
• - shaped by extrusion
• - Rolling
• - Cold drawing
• PM injection molding
• - Very intricate geometry
• - Good mechanical property

3
Ferrous non-ferrous powders

• Ferrous powders and non-ferrous powders capable
• - ONLY if subsequent heat treatment is
• performed (to achieve desired strength
• and hardness)

4
Without secondary heat treatment

• Usually mixing, compaction, sintering, and heat
  treatment
• To AVOID Secondary Heat Treatment
• Heat treatment integrated into sintering
• - Decreasing temp. as parts exit
  sintering
• - Quenching in oil
• Surface finishing
• Steam treating to produce black-oxide finish
• Impregnation with oil