1. What is an Injection Molding Tonnage Calculator?

Definition: This calculator estimates the required clamping force (in tons) for an injection molding machine based on part geometry and process parameters.

Purpose: Helps manufacturers select the appropriate machine size and prevent defects like flash by ensuring sufficient clamping force.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( T \) — Required clamping force (tons)
• \( A \) — Projected area of part and runners (in²)
• \( P \) — Injection pressure (psi)
• \( SF \) — Safety factor (typically 1.5-2)

Explanation: The formula calculates the force needed to keep the mold closed against injection pressure, with a safety margin.

3. Importance of Tonnage Calculation

Details: Proper tonnage estimation prevents mold flashing, ensures part quality, and helps select cost-effective machinery.

4. Using the Calculator

Tips: Enter the projected area (including runners), injection pressure (default 5000 psi), and safety factor (default 1.5). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is projected area?
A: The total area (including runners) seen when looking perpendicular to the mold's parting line.

Q2: What's typical injection pressure?
A: Most processes use 3000-8000 psi, with 5000 psi being a common starting point.

Q3: When would I increase the safety factor?
A: For complex parts, thin walls, high viscosity materials, or critical applications.

Q4: How do I find projected area?
A: Use CAD software or calculate part dimensions (length × width for simple geometries).

Q5: What if I get a very high tonnage?
A: Consider reducing part size, using multi-cavity molds, or optimizing gate locations.