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Process Physics

Flange Bending vs. Dome Expansion

In rubber pad forming (elastoforming), the deformation mechanism dictated by workpiece geometry fundamentally changes how tonnage requirements are calculated. Selecting the appropriate process mode in the calculator ensures accurate hydraulic press sizing for aviation, automotive, and general sheet metal components.

Engineering Deep Dive: To explore the underlying hyperelastic constitutive models and stress-strain mechanics governing these deformation modes, read The Complete Engineering Guide to Rubber Pad Forming and Elastoforming.

Straight / Flange Bending Mode

Deformation Behavior: Primarily localized linear strain along the neutral axis. The flexible rubber pad acts as a dynamic female die, enveloping the sheet over a rigid male form block.
Force Characteristics: Governed by classic bending moment calculations. Lower hydraulic pressure is required because material flow is restricted to local bend radii rather than multi-directional tensile stretching.

Hemisphere / Dome Expansion Mode

Deformation Behavior: Bi-axial circumferential tension across the entire unsupported blank area. The metal undergoes uniform thinning and permanent plastic stretching until it conforms to the cavity die.
Force Characteristics: Based on hoop stress and ultimate tensile strength (F = π * D * t * TS). Requires substantially higher hydraulic pressure to force the elastomeric pad into deep 3D contours without wrinkle formation.
Engineering Note: Always account for the elastomeric pad’s hardness (Shore A rating) and volumetric containment pressure. For high-strength alloys like Stainless Steel 304/316 or Aerospace Aluminum 7075-T6, incorporating a minimum 1.35x safety factor prevents hydraulic stall during bottoming out.

Rubber Pad Forming Calculator

Engineering estimation for hemisphere dome expansion and flange bending forces.

1. Material Properties

2. Part & Process Geometry

Theoretical Forming Force: 33.4 Metric Tons (36.8 US Tons / 327.3 kN)
Recommended Press Capacity: 45.1 Metric Tons (49.7 US Tons)
(Includes 1.35x Safety Factor | Standard Commercial Press Rating: 50 Tons)
EQUIPMENT SPEC

From Calculation to Real Production:
Explore BITAERON High-Pressure Rubber Pad Presses

Now that you’ve estimated your required forming pressure and tonnage, discover our heavy-duty Rubber Pad Forming Press series engineered to handle ultra-high pressure, reduce cycle times, and eliminate hand-fettling for complex aerospace parts.