How to Perform Sealing Tests After Magnesium Oxide Refilling

The core method for sealing tests after magnesium oxide refilling is to combine airtightness testing, moisture testing, and X-ray inspection with visual inspection to ensure the seal is defect-free. These methods effectively verify IP65 or higher protection ratings, preventing moisture and dust intrusion that could lead to insulation failure.

1. Airtightness Test (Pressure Holding Method)

Operation Method: Apply 0.3MPa compressed air or nitrogen to the heating element and hold the pressure for 30 minutes;

Pass Criteria: No pressure drop, no leaks;

Testing Tools: High-precision digital pressure gauge + sealing joint device;

Applicable Stage: Batch testing before shipment or after repair.

This is the most direct method for verifying sealing and can detect even minute leaks.

2. Moisture Test (Environmental Simulation Method)

Test Conditions: Place in an environment of 40℃ and 95% relative humidity for 48 hours;

Subsequent Inspection: Measure the insulation resistance immediately after removal, with a standard of ≥200 MΩ (500V DC);

Significance: Simulates high humidity conditions to verify the moisture resistance of the sealed structure;

Risk Warning: A sudden drop in resistance indicates that moisture has penetrated into the insulation layer.

This test must be performed after the component has completely cooled to avoid condensation from temperature differences interfering with the results.

3. X-ray Inspection (Non-destructive Testing Method)

Key Inspection Points: Whether there are micropores, misalignments, insufficient filling, or cracks in the sealing area;

Resolution Requirements: The equipment should have a resolution of ≥5μm, capable of identifying micron-level defects;

Applicable Scenarios: High-end applications (such as medical, aerospace) or fault analysis;

Advantages: Non-destructive, allowing for comprehensive assessment of the internal structural integrity.

In practice, X-rays can detect sealant shrinkage cavities or metal weld bubbles that are invisible to the naked eye.

4. Appearance and Process Parameter Verification