Views: 0 Author: Site Editor Publish Time: 2025-08-14 Origin: Site
The tonnage of an injection molding machine refers to its clamping force—the amount of pressure (measured in tons) that the machine can apply to keep the mold closed during injection.
Why is it important?
Prevents mold from opening due to high injection pressure.
Ensures part quality by minimizing defects like flash (excess material leakage).
The required clamping force depends on:
Formula:
Clamping Force (tons)=Projected Area (in² or cm²)×Injection Pressure (psi or MPa)×Safety Factor (1.2-1.5)Clamping Force (tons)=Projected Area (in² or cm²)×Injection Pressure (psi or MPa)×Safety Factor (1.2-1.5)
Example:
50×40×0.001=20 tons (minimum)50×40×0.001=20 tons (minimum)
Adding a safety factor (1.3x), the required machine tonnage would be 26 tons.
If a part has a projected area of 50 cm² and requires 40 MPa injection pressure:
High-viscosity materials (e.g., PC, Nylon) require higher pressure, increasing tonnage needs.
Low-viscosity materials (e.g., PP, HDPE) need less clamping force.
| Clamping Force (tons) | Typical Applications |
|---|---|
| 20-50 tons | Small gears, buttons, electronic components |
| 80-150 tons | Mobile cases, toys, household items |
| 200-350 tons | Automotive parts, large containers |
| 400-600 tons | Car bumpers, appliance housings |
| 800+ tons | Pallets, large industrial parts |
Part Size & Complexity – Larger/thicker parts require higher tonnage.
Material Selection – Engineering plastics (e.g., ABS, PC) need more force than standard resins.
Mold Design – Multi-cavity molds increase required clamping force.
Energy Efficiency – Higher-tonnage machines consume more power; balance performance with cost.
Shot Capacity (in grams/ounces) – Must match part weight.
Mold Size & Platen Dimensions – Ensure the machine can accommodate your mold.
Tie-Bar Spacing – Determines maximum mold width.
Choosing the right injection molding machine tonnage is crucial for producing high-quality plastic parts efficiently. By calculating the required clamping force based on part design and material, manufacturers can optimize performance while minimizing costs.
Need help selecting a machine? Consult with an injection molding expert to ensure the best fit for your production need.
