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FINEBLANKING
CAPABILITIES
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Fineblanking
101
Fineblanking produces stamped parts with a clean, 100% sheared edge. This edge is the result of special tooling and a special press. To understand why this is necessary, we need to first look at the reasons why a part fractures and then how the Fineblanking Process works to overcome these conditions. 1.) Tool Clearance |
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In conventional stamping, clearances run 10-20% the thickness of the material. This allows the punching stress to be relieved by fracturing. In fineblanking, clearances run from .0001" to .0003", which does not allow edge fracturing. 2.) Material Movement to Relieve Stress |
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| In Fineblanking, the material is held in constraint by a special hydraulic clamping system in the press. | |
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| In many situations, "impingement" is added to the clamp action to stop material from flowing away from the punch. This is a V-shaped protrusion that runs around the edge of the die opening. | |
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The final element is counter force. An additional die element is added which mirrors the shape of the punch. Pressure is applied to this element throughout the process. This keeps the part from bowing away from the punch, resulting in an extremely flat part. 3.) Bringing it all together When all of these conditions have been satisfied, that is, minimal punch clearance, material clamping pressure and counter pressure the fine blanking process can occcur. The part is now being extruded from the strip, as opposed to being fractured away. This actually flows the material parallel to the edge of the part. Forming a work hardened layer that improves the functioning of the part. |
| FINEBLANKING
DESIGN GUIDE
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