Quick Q&A: How does airtightness testing really work? How to define airtightness testing standards

In the manufacturing quality control system, "Air tightness testing" is an extremely critical process.

Whether it's a new energy vehicle battery shell, a waterproof structure for home appliances, or a medical device encapsulation module, strict airtightness tests must be passed to ensure that the product does not leak air or water under the working environment.

This article will provide an in-depth analysis:How is airtightness testing done? How are airtightness testing standards defined?And combined with domestic representative brandsJingcheng Gongke (JCGK)The practical application of the system builds a systematic understanding for you.

Ⅰ. What is airtightness testing?

Air Tightness Test (Leak Test / Air Tightness Test) is a test method to determine the sealing performance of a product by applying positive or negative pressure to the inside of the product and monitoring the pressure change.

put it simplyThat's what I'm talking about.Determine if the product is leaking air, water, or sealing poorly"The Detection Process.

According to the structure and requirements of the test object, airtightness testing can generally be divided into the following categories:

Detection method	Test Principle	typical application
positive pressure	Fill the cavity with a certain pressure, hold the pressure and detect the pressure drop change	General-purpose parts, electronic housings
Negative pressure method (vacuum method)	Evacuate the sample and check the rate of pressure buildup	Medical Devices, Packaging Modules
flow rate method	Monitoring of the air leakage rate by means of a flow meter	Piping, valve assemblies
volumetric quantification	Measurement of inflation volume differences to determine leakage	Fully enclosed structure, module testing
differential pressure	Leakage is determined by comparing the pressure difference between the measured part and the standard part.	High-precision parts and die castings
Helium test / Water test	Helium mass spectrometry or real water immersion for very small leaks or strong waterproofing tests	New energy battery, waterproof grade verification

II. Step-by-step process for airtightness testing

In automated production, standard airtightness testing is generally divided into five core steps:

1. Sealing Fixture Positioning::
   Ensure that the interface between the product to be tested and the testing equipment is completely sealed, high-precision fixtures are the key to the stability of the test.
2. Inflating (or evacuating)::
   Apply a set pressure (e.g. +50kPa or -30kPa) according to the detection principle.
3. stabilization phase::
   Maintain pressure stabilization to eliminate system inertia and environmental disturbances.
4. testing phase::
   The pressure change over time (ΔP) is monitored and the leakage rate is calculated based on an algorithm.
5. Judgment and Output::
   The equipment automatically determines "pass/fail" according to the standard limit values and outputs data reports or traceability records.

With Jingcheng Gongke (JCGK)'sAirtightness TesterFor example, the device supports multi-channel testing and MES system linkage.
Pressure control, data acquisition and result analysis can be done automatically to realize the0.1Pa level accuracy detection and fully automatic sorting outputsThe

III. How are airtightness testing standards defined?

The development of standards for airtightness testing is a comprehensive process, with definitions derived from two main levels:

1. Macro basis (source of criteria):
First, standard setting isBased on years of mature experience and technology accumulation in the industryand must refer to and follow establishedInternational standards (e.g. ISO) or Chinese national standards (e.g. GB)This provides the underlying framework for the test methodology, and the basis for the determination. This provides the underlying framework for the test methodology, and the basis for the determination.

2. Micro-factors (specific applications):
Second, the precise definition and parameterization of standards for a particular product(e.g., test pressure, leak rate)be sure toDepends largely onHere are a few key factors:

• product mix: Product design, volume, material and sealing method.
• work pressure: The internal or external pressure to which a product is subjected during actual operation.
• application environment: The environment in which the product is located, such as temperature, humidity, and whether it is in contact with liquids.
• protection class: the standard of protection that the product needs to meet, in particular IP Protection Rating / ATM Water Resistance RatingThe

Attention:
For products with explicit waterproofing certification requirements (e.g., IP67, IP68, or 5ATM), theAirtightness testing standards mustCorresponding to the waterproofing requirements of these classes. This means that parameters such as test pressure need to be converted toequivalence simulationand meet the test conditions required for that waterproofing rating.

Ⅳ. How to ensure stable and reliable test results?

There are many factors that affect the accuracy of hermetic testing, includingTemperature drift, fixture sealing, environmental interference, sensor accuracyetc. To achieve consistent test results over time, a two-pronged approach is needed at both the equipment and standards levels:

1. Device level optimization

• Selection of high-precision pressure sensors and pressure stabilization control system;
• Add temperature compensation and auto-calibration function;
• The detection channels have a modular and independent structure to prevent cross-interference.

Precision Engineering'sMulti-Channel Air Tightness TesterSupport independent analysis and judgment, independent display, independent setting parameters, built-in temperature compensation function.

Precision Engineering Customized for Overseas CustomersFour-channel airtightness meter

2. Standard level management

• Establishment of a mechanism for testing benchmark samples and comparisons of product counterparts;
• Perform equipment calibration on a shift/daily basis;
• Ensure that fixture seals are regularly replaced with a leakage self-test process.

Precision Industrial Technology (PIT) has announced in itsFully automatic air tightness test platformIntelligent compensation algorithm and multi-point calibration system have been introduced in the "CMM," which can effectively reduce the errors caused by environmental fluctuations and realize theRepeatability better than ±0.2%F.The

V. Ideas for developing enterprise-level airtightness testing standards

For manufacturing companies, the development of "their own airtightness testing standards" can usually be divided into the following stages:

1. Requirements analysis phase::
   Specify the sealing requirements of the product in the use scenario (e.g., water pressure, dust, oil and gas, etc.).
2. Pilot validation phase::
   Determine appropriate pressure values and leakage limits through experimentation, resulting in an internal validation report.
3. Standards finalization phase::
   Prepare the "airtightness testing operation guidebook" to clarify the test conditions, equipment models, and judgment standards.
4. Implementation and retrospective phases::
   With the help of intelligent testing system, the test data can be traced, counted and audited.

JCGK can provide standardized and customized services for different enterprises, from experimental verification, fixture design, to mass production line data system integration, to help customers establish testing standards in line with ISO9001 and industry certification system.

Summarize

The essence of airtightness testing is "theSeal reliability verified in a scientific way", and the development of testing standards is "to find the optimal balance between safety and productivity".

In the actual project, companies should:

• Pressure and leakage limits are defined according to product characteristics;
• Select stable and reliable airtightness testing equipment;
• Establishment of internal standards and traceability systems.

Domestic representative brand "JCGK".With multi-detection principle support, high-precision control and industry experience, it is becoming a trusted partner for many manufacturing companies in the field of waterproofing and sealing inspection.

Original Statement:this paper was written byShenzhen Jingchenggongke Technology Co., Ltd.Written by the technical team, reproduced with attribution.Data sources:Precision Engineering internal test data and customer cases.