Flattening Force Calculator

Estimate the elevated tonnage required for flattening, hemming, coining, and bottoming operations.

Flattening, hemming, bottoming, and coining force the material against the die instead of just bending it in air. That demands far more tonnage than air bending — but it sets the form and kills springback.

Formula: Bottoming/coining tonnage ≈ Air-bend tonnage × (3 to 10)

Worked Example

  1. A bend that air-forms at 9 tons/ft may need 30–90 tons/ft to coin.
  2. Confirm the press and tooling can handle the multiplied load before bottoming.

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