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Do you know the three key requirements for automotive connector sealing tests?

Release time：

2022-10-11

1. Sealing Test: The sealing performance of the test connector must be verified under vacuum or positive pressure conditions. Typically, the product is sealed using a fixture and then subjected to an airtightness test at a positive or negative pressure ranging from 10 kPa to 50 kPa. The allowable leakage rate is no more than 1 cc/min; for higher‑specification requirements, the limit is 0.5 cc/min. Only products meeting these criteria are deemed合格 (qualified).

1. Sealing Test: The sealing performance of the test connector must be verified under vacuum or positive pressure conditions. Typically, a positive or negative pressure ranging from 10 kPa to 50 kPa is applied, and after securing the product with a fixture, an air‑tightness test is conducted. The measured leakage rate shall not exceed 1 cc/min; for higher‑specification requirements, the limit is 0.5 cc/min. Only products meeting these criteria are deemed合格 (qualified).

2. Pressure‑withstand testing: This test is divided into negative‑pressure and positive‑pressure tests. For the test, a precisely calibrated proportional‑control valve assembly is selected. Starting from an initial pressure of 0 kPa, the product is evacuated at a specified pumping rate, with both the duration of evacuation and the target vacuum level being adjustable. For example, one might set the target vacuum to −50 kPa, with a pumping rate of 10 kPa/min. The main challenge lies in requiring the leak‑testing or air‑tightness tester to allow setting the initial pressure for negative‑pressure evacuation—for instance, starting from 0 kPa—or even from −10 kPa—and to enable adjustment of the pumping rate, which must also be programmable. As is well known, sealing‑test instruments and air‑tightness testers are typically equipped with manual or electronic pressure regulators that can only adjust pressure to pre‑set values, always beginning from 0 kPa. The ability to generate vacuum depends on the vacuum source—whether a vacuum generator or a vacuum pump—and once the pressure is regulated by the control valve, the evacuation rate becomes fixed: the system can only instantaneously reduce the pressure from 0 kPa to the fixed value set on the regulator, without the capability to modulate the pressure‑time relationship according to different ratios. The principle underlying positive‑pressure pressure‑withstand testing is similar to that of negative‑pressure testing: the initial positive‑pressure level can be set arbitrarily—e.g., 0 kPa or 10 kPa—and the slope (rate of pressure increase) is likewise adjustable, such as 10 kPa/min. The test requires that the pressure rise and the elapsed time be proportionally adjustable.

3. Burst Testing (Pressure‑Breakage Testing): This is divided into negative‑pressure burst testing and positive‑pressure burst testing. The product must rupture instantaneously when subjected to a specified vacuum or pressure range, and the rupture pressure must be recorded. The main challenge lies in meeting the second test requirement: the leak‑testing instrument must generate a negative pressure that satisfies the specified criteria, with an adjustable pressure‑rise rate, while ensuring that the burst occurs strictly within the set pressure limits—no overshoot or undershoot is permitted. In other words, any burst below or above this range would fail to meet the test requirements, and the exact burst pressure must be documented. During actual testing, a safety‑enclosure system is essential. Typically, the test specimen is placed inside a pressure‑resistant stainless‑steel chamber, which is sealed. A high‑pressure relief valve is installed on the outer stainless‑steel enclosure to ensure safety. When the burst occurs, fragments of the connector remain confined within the pressure‑rated chamber, preventing injury to personnel. As outlined above, leak‑testing instruments generally require three distinct subsystems to perform these functions: sealing‑leak testing is conducted using a dedicated leak detector paired with a fixture system; pressure‑resistance testing necessitates an additional proportional‑control valve assembly to precisely set both the pressure value and its time‑based profile; and burst testing demands that the product rupture within a defined pressure range, with the rupture pressure duly recorded. Integrating these three systems results in a rather complex engineering solution. Moreover, these three tests are often required to be performed concurrently. The initial pressure can be set arbitrarily, and the rate of pressure increase or decrease is adjustable. Once the pressure reaches the threshold for triggering the burst—within the pre‑set range—the instrument records the burst pressure. If, upon reaching that threshold, the product fails to burst, the system proceeds directly to sealing‑leak testing, documenting the leakage rate or the pressure change per unit time. At the conclusion of testing, all results must be stored for quality traceability. All test data must be traceable and formatted according to prescribed standards for storage and upload, facilitating quality analysis and control. Specifically, regarding sealing‑leak testing, European and American automotive manufacturers impose the following requirements: prior to testing, the part’s barcode must be scanned and recorded; after testing, the barcode must be linked to the corresponding test results, including date and time.

Shenzhen Linkconn Electronics Co., Ltd.

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E-Mail：szlcn@linkconn.com
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