A sealing test should be performed immediately after magnesium oxide refilling, once sintering has cooled to room temperature and cold-state testing has been completed, typically within 3–5 hours of the start of sintering. The timing of the test directly affects the accuracy of the results; it is essential to ensure the components are fully cooled and the environment is dry.
Sealing Performance Testing Timeline and Key Milestones
|
Stage |
Time |
Description |
|
Sintering and Holding |
1–2 hours |
Complete grain recrystallization at 800–1000℃ to improve structural stability |
|
Natural Cooling in Furnace |
1–2 hours |
Cool with the furnace to <200℃ to prevent thermal stress-induced cracking |
|
Cooling to Room Temperature After Removal |
30–60 minutes |
Ensure temperature stability at around 25℃ to avoid condensation affecting testing |
|
Cold Performance Testing |
≤30 minutes |
Confirm basic electrical performance through insulation resistance (≥500 MΩ) and withstand voltage tests |
Sealing performance testing should be performed immediately after the above procedures are completed, and can be started as early as 3 hours after sintering begins, but it must be confirmed that the component has completely cooled and there is no residual heat.
Recommended Testing Items and Sequence
Visual Inspection
Check for bubbles, cracks, or shrinkage cavities in the sealing adhesive; Check for continuous and uniform metal welds, without incomplete or broken welds.
Airtightness Test (0.3MPa pressure hold for 30 minutes)
Standard: No pressure drop, no leaks; Use a high-precision digital pressure gauge and sealing joint device.
Pre-dampness Test (Optional)
Record the initial insulation resistance (≥500 MΩ) to provide a benchmark for the subsequent 48-hour dampness test.
X-ray Inspection (Required for high-end applications)
Inspect the sealing area for hidden defects such as micropores, misalignment, or insufficient filling.
