Design Considerations Conventional Compaction

1
Design ConsiderationsConventional Compaction

• Stephen G. Baker
• Allied Sinterings, Inc.
• June 2002

2
Size limitations

• Component size governed by press tonnage
• ASI capable of 1.25 in2 face area by approx 1 in
  thick.
• Lightening holes can reduce face area
• Smallest part lt0.005 in2 !!!

3
Tolerances

• Die dimensions
• /- 0.002 possible as sintered, sizing an option
• /- 0.0005-.0001 on small IDs
• Press dimensions
• Prefer /- 0.005 Can do /- 0.002
• Easier to hold tighter tolerances on ferrous
  steels than stainless or non ferrous
• Other factors must be considered

4
Tolerance factors

• Orientation
• Size (flatness, thickness)
• Complexity
• Powder
• Tool wear
• Heat treat
• Secondary operations
• Application

5
Die considerations

• Avoid long, thin tool members which result in
  fragile tooling, sharp corners, and powder fill
  issues. (A)

6
Thin punches

• Avoid thin punches, allow 0.060 between features
  in die.
• 61 fill ratio maximum

7
Punch considerations

• Avoid designs which require feather edges on
  punches

8
Tooling concerns

• Avoid
• abrupt changes,
• localized thin walls
• sharp corners
• undercuts

9
Chamfers

• Use 30 degree on chamfers or add flat
• IDs use 120 degree included angle x .005

10
Screw Countersinks

• Add flats to the bottom of screw head
  countersinks.

11
Radius on Edge

• Radii on edge of part results in knife edge on
  punch. Use 30 degree chamfer or add flat

12
Gears with Hubs

• Hubs should be as far as possible from root of
  gear teeth

13
Protrusions

• Avoid thin protrusions and and join them using
  radii

14
Punch faces

• Face form features no greater than 20 of height.

15
Top punch recess

• Features, such as hubs, created by top punch
  should be no greater than 15 of total height.
  Up to 12 degree draft.

16
Top Features

• Features created by top punch no greater than 15
  of overall height.

17
Core rod configurations

• Many configurations are possible, including
  splines, internal gears.

18
Recesses

• Avoid deep recesses, especially created by upper
  punch

19
Tapered core rods

• Allow flats on top on bottom of tapered core rod.

20
Composite part
21
Acknowledgement

• Pictures from Powder Metallurgy Design Manual,
  Third Edition, 1998