1. What is Shot Size in Injection Molding?

Shot size refers to the total volume of material required to fill all cavities in an injection mold. It's a critical parameter in injection molding that determines the machine capacity needed for production.

2. How Does the Calculator Work?

The calculator uses the shot size formula:

Where:

• \( \text{Cavity Volume} \) — Volume of a single cavity (cm³)
• \( \text{Number of Cavities} \) — Total number of cavities in the mold

Explanation: The formula calculates the total material volume needed by multiplying the volume of one cavity by the total number of cavities in the mold.

3. Importance of Shot Size Calculation

Details: Accurate shot size calculation ensures proper machine selection, prevents short shots or excessive material use, and helps optimize production efficiency.

4. Using the Calculator

Tips: Enter cavity volume in cm³ and number of cavities. Both values must be positive numbers (volume > 0, cavities ≥1).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between shot size and shot capacity?
A: Shot size is the required material volume, while shot capacity is the machine's maximum capability. The machine's capacity should exceed your shot size.

Q2: Should I include runner volume in the calculation?
A: This calculator focuses on cavity volume. For total material requirement, you would need to add runner and sprue volumes separately.

Q3: How do I determine cavity volume?
A: Cavity volume can be calculated from CAD models or by measuring the weight of a filled part and dividing by material density.

Q4: What safety factor should I add?
A: Typically 10-20% extra is added to the calculated shot size to account for variations and ensure complete filling.

Q5: Does material shrinkage affect shot size?
A: Shrinkage affects part dimensions but not the initial shot size calculation, as the mold cavities are designed to account for shrinkage.