KEVOS® MAKEOS · Fabrication
Shearing Force for Parallel and Inclined Blades
What force does it take to shear this sheet or bar, with parallel or inclined (rake) blades?
Shearing force for straight parallel blades from the shear strength and cut area, and for straight inclined (raked) blades from tensile strength, thickness, blade angle and the relative penetration, with the handbook’s 30% machine allowance and a capacity check.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Blades | choice | Parallel blades shear the whole length at once; inclined blades cut progressively. |
| Material thickness | mm | Thickness of the material. |
| Length of cut (parallel blades) | mm | Length of the cut with parallel blades. |
| Shear strength (parallel) | MPa | Shear strength of the material. |
| Tensile strength (inclined) | MPa | Ultimate tensile strength of the material. |
| Blade inclination | ° | Angle of the upper blade to the lower. |
| Factor n (inclined) | Factor n, about 0.75–0.85 for most materials (handbook). | |
| Ratio of shear to tensile strength k (inclined) | Shear-to-tensile strength ratio, about 0.7–0.8 (handbook). | |
| Relative penetration ε (inclined) | Relative penetration of the blade at fracture (falls with thickness and hardness; from shear data). | |
| Machine capacity | kN | Rated capacity of the shear or press. |
Method and formulas
- Parallel blades: F = τ b T.
- Inclined blades: F = n k UTS ε T² ÷ tan α.
- Machine force = 1.3 F, allowing for blade clearance, thickness variation and edge wear.
- Example: 3 mm sheet at 2° rake needs about 48.246 kN at the machine.
Limitations
- Approximate formulas; blade clearance and sharpness change the force considerably.
- Inclined blades need a longer stroke and may twist narrow strips.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check whether a guillotine can cut a plate
- Choose a rake angle to cut the force
- Estimate shear force for a cut-off die
Who it is for
- Fabrication supervisors
- Toolmakers
- Manufacturing engineers
What you get
- Shearing force
- Machine force with allowance
- Capacity check
Interpreting the result
- A small rake angle greatly reduces force on long cuts; plate shears exploit this.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1336–1338. Topic reference; no source tables or recommended settings are reproduced.
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Open the Shearing Force for Parallel and Inclined Blades calculator
