Hole Punching Tonnage Calculator

Punching Tonnage Formula:

\[ T = \frac{P \times t \times S}{2000} \]

Required Tonnage (tons):

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1. What is a Hole Punching Tonnage Calculator?

Definition: This calculator estimates the force required to punch a hole in sheet metal based on material properties and punch geometry.

Purpose: It helps metal fabricators determine the appropriate press brake or punch press tonnage needed for specific operations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ T = \frac{P \times t \times S}{2000} \]

Where:

\( T \) — Required tonnage (tons)
\( P \) — Punch perimeter (inches)
\( t \) — Material thickness (inches)
\( S \) — Material shear strength (psi)

Explanation: The formula calculates the total force needed by considering the length of cut (perimeter), material thickness, and material strength.

3. Importance of Tonnage Calculation

Details: Accurate tonnage calculation ensures proper machine selection, prevents tool damage, and maintains production quality.

4. Using the Calculator

Tips: Enter the punch perimeter, material thickness, and shear strength (default 45,000 psi for mild steel). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the 2000 divisor for?
A: It converts pounds-force to tons (1 ton = 2000 lbs).

Q2: How do I calculate punch perimeter?
A: For round holes: π × diameter. For other shapes, sum all side lengths.

Q3: What's a typical shear strength for mild steel?
A: About 45,000 psi, but varies by alloy and hardness.

Q4: Should I add a safety factor?
A: Yes, consider adding 20-30% to the calculated tonnage for tool wear and material variations.

Q5: Does this account for die clearance?
A: No, this is a basic calculation. Die clearance affects actual tonnage needed.