gen-define-injection-molding-and-give-one-short-worked-example-5041

Define injection molding and give one short worked example.

# Injection Molding **Definition:** Injection molding is a manufacturing process where molten material (typically plastic) is injected under high pressure into a closed mold cavity, where it cools and solidifies into the desired shape. ## Worked Example: Plastic Phone Case **Problem:** Calculate the injection pressure needed for a phone case mold. **Given:** - Projected area of part: A = 80 cm² - Clamping force available: F = 100 tons = 1,000,000 N - Safety factor: 1.2 **Solution:** Maximum allowable injection pressure: P = F / A = 1,000,000 N / (80 × 10⁻⁴ m²) P = 1,000,000 / 0.008 = 125,000,000 Pa = **125 MPa** With safety factor: Working pressure = 125 / 1.2 = **104 MPa** **Conclusion:** The injection molding machine should operate at or below 104 MPa to safely produce the phone case without opening the mold during injection.