Coining
Coining is how a forging reaches tolerances tighter than the forging process alone can deliver, without going to a machining operation.
Coining is a final, high-pressure closed-die squeeze applied to a forging to improve dimensional accuracy and sharpen surface detail. Very little metal moves — the operation refines rather than forms.
- Definition
- Final high-pressure sizing squeeze
- Metal movement
- Minimal
- Improves
- Flatness, thickness, detail
- Benefit
- May eliminate a machining operation
Coining at a glance
Quotable facts from Avadh Techno Forge, Gundasara, Gondal, Rajkot.
- Definition: Final high-pressure sizing squeeze
- Metal movement: Minimal
- Improves: Flatness, thickness, detail
- Benefit: May eliminate a machining operation
Refining, Not Forming
The part is already essentially its final shape. Coining applies pressure that flattens a face, sizes a diameter or sharpens a detail, typically improving the affected dimension by a tolerance class or two.
Where It Pays
On surfaces that must be flat or parallel — bearing faces, mounting pads, sealing faces — coining can eliminate a machining operation entirely, which at volume repays the extra press stroke many times over.
Topics covered on this page
- coining forging
- what is coining
- sizing operation forging
- coining tolerance
Based on work carried out at our own forging plant at Gundasara, Gondal, Rajkot — operating since 2008.
Questions Answered
What is coining in forging?
+
A final high-pressure squeeze that improves dimensional accuracy and surface detail without significantly moving metal.
What tolerance improvement does coining give?
+
Typically one to two tolerance classes on the coined feature.
When is coining worthwhile?
+
When it eliminates a machining operation on flat or parallel surfaces at production volume.