Today's KNOWLEDGE Share : "Clamping Force vs. Mold Weight"

Today's KNOWLEDGE Share

How to Correctly Use the "Clamping Force vs. Mold Weight" Correlation in Injection Molding

We often discuss the theory behind machine selection. Today, let's talk about the practical application. Understanding the non-linear relationship between mold weight and required clamping force is crucial, but it's only a guideline. Safety and precision come from a disciplined process.

Here’s a practical, two-way method to apply this knowledge and avoid costly mistakes.

1. Forward Estimation (The Right Way: From Product to Machine)

This is the standard, proactive approach for new projects.

Step 1: Calculate. Determine the required clamping force scientifically based on your part's projected area and material injection pressure. This is your non-negotiable starting point.

Step 2: Estimate Weight. Based on the part size and complexity, estimate your mold weight.

Step 3: Cross-Reference. Use the force and weight to check a correlation table . This gives you a target machine class (e.g., 600-1200T).

Step 4: Verify Specs. This is critical. For a specific machine in that class,

you MUST verify three physical parameters from its manual:

✅ Tie-Bar Clearance (will the mold fit?)

✅ Mold Thickness Range (is it too thick/thin?)

✅ Maximum Allowable Mold Weight (is it safe?).

2. Reverse Warning (The Safety Check: For Existing Tools)

This is your rapid risk-assessment tool, especially when repurposing a mold.

Scenario: You have a mold weighing, for example, 10 tons.

Check the Table: A 10-ton mold typically requires a 1500+ ton machine for safe structural support.

The Red Flag: If someone suggests running it on an 800-ton press, you now have a data-backed reason to say "Stop." Even if the clamping force might be borderline sufficient, the machine's platens and tie bars are not engineered for that static load and dynamic inertia. This prevents catastrophic damage.

The Key Takeaway?

The correlation table is your quick-screening ally, but the machine's official technical specification sheet is your binding contract for safety.

Industry Wisdom: Experience helps you ask the right questions, but only hard data from the manufacturer gives you the right answers.

What's your process for machine-mold validation?

source : Kim Su

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