One-sentence answer: The sealing of a high-voltage connector relies on the compression fit between the terminal sealing ring and the housing. Insufficient compression allows water ingress, while excessive compression causes permanent deformation, and terminal burrs scratching the sealing ring during assembly can cause internal damage. Using the CTS Sentinel A28 differential pressure leak detector to compare a master part with the part under test enables stable judgment within a small volume and a short time window, making it suitable for 100% inspection of high-voltage connectors in large batches.
Sealing relies on the compression fit between the terminal seal rings and the housing: too little leaks, too much deforms permanently
After the tolerances of the terminal, sealing ring, boot, and housing stack up, the compression may fall at the lower limit, leaving insufficient contact stress on the sealing face and allowing water ingress; it may also fall at the upper limit, causing the sealing ring to be flattened over time and lose its resilience.
Burrs on the terminal and boot, insufficient chamfers, and misalignment during assembly can all cut the sealing ring at the moment of insertion; the damage is hidden inside the mating face and cannot be found by appearance or electrical testing.
Each cavity of a multi-core connector is sealed independently, and failure of any single cavity rejects the entire connector, making yield extremely sensitive to single-cavity leakage.
Once a high-voltage circuit short-circuits due to water ingress, the consequences involve personal safety, so the supply chain can only place interception at the connector ex-factory stage.
Sealing locations:
Consequences of leakage: moisture enters the mating interface, causing creepage, reduced insulation resistance, and terminal corrosion; in severe cases, short circuits between positive and negative poles, partial discharge, and the risk of electric shock to personnel, while also causing the vehicle's IP protection and high-voltage safety requirements to fail.
High-voltage connectors are typical workpieces with small volume, large batch size, and fast cycle time, and their repeatability requirements are higher than absolute sensitivity:
It depends on the product's sealing design. If the sealing ring only forms compression after mating, testing must be performed with a fixture that simulates mating; otherwise, the tested state does not match actual use. If sealing is completed independently by the connector's own structure, both ends can be plugged directly for testing. The specific basis is the sealing definition in the product drawing.
It can detect damage that has already affected sealing. When a scratch causes insufficient local contact stress, the cavity leak rate will exceed the test program limit and be rejected. As for shallow scratches that do not break the seal, air tightness testing does not reflect them, and they should be addressed through assembly process control and incoming burr control.
Because the consequence of a single-piece failure is the risk of high-voltage short circuit and electric shock, and sealing ring damage is random and not fully correlated with batch yield. Sampling inspection cannot cover individual units whose compression falls at the lower limit; 100% inspection with records retained is the approach that matches OEM requirements.
The core of sealing testing for high-voltage connectors is to intercept compression deviation and assembly damage before shipment. The CTS Sentinel A28 uses differential pressure comparison to achieve stable judgment of small-volume workpieces, and with a mating simulation fixture and 32 test programs, it meets the 100% inspection and data traceability requirements of high-volume production lines for high-voltage connectors.
WeChat for technical support
PLUS Douyin
