Q&A: Product airtightness testing NG up? 1-minute precise location of the leak point of the practical method

Engineers on the manufacturing end have encountered a mind-numbing scenario:
Airtightness TesterObviously the NG was reported, but after taking apart the defective product and looking at it for half a day, I still can't see where exactly it is leaking.

This situation is like a doctor telling you "you have a fever" but not telling you where the infection is.
It delays line efficiency, increases rework costs, and seriously interferes with quality judgment.

Precision EngineeringTrue Water TesterOne-step leak localization

So how exactly do you find a leak efficiently and accurately when there is a bad leak in an airtightness test?

Time is money. For every minute the production line is stalled, the losses accumulate. Today we talk about.How to find the leak in the fastest way when the hermeticity test reports NGThe

Ⅰ. Blind spot of airtightness testing: can measure leakage, can't locate it

Let's get one fact straight:airtightness testerfaultLeak LocatorThe

It can tell you exactly whether the product is leaking by monitoring pressure drop changes, flow fluctuations, and pressure curves to determine whether the product is leaking:

• Did the product leak?
• What is the amount of leakage?

But it couldn't answer:

• Where the hell is it leaking from?

That's why.airtightness meterWith NG, you still have to find another way to find the leak.

Ⅱ. Traditional Leakage Finding Methods: Slow, Inaccurate, Relying on Luck

① Blind dismantling method (most traditional, but least efficient)

The most primitive approach:拆The

Remove seal, test once, still leaking. Remove the screws, test once, still leaking. Remove the upper and lower shells, remove the interface, replace the rubber ring, reassemble, test again, disassemble again, test again ......

The scientific name for this method is.exclusionary law".

The problem is obvious:

• At least half an hour for a product disassembly round
• Extremely high labor costs
• Products prone to secondary damage
• Completely unsupported by data

Modern factories don't use this method anymore.. However, in many small factories, this is still the dominant practice.

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② Soaking method (bubbles can be seen, but drawbacks are obvious)

Soak the product in water and manually inflate it to see where it bubbles.

This method is a bit of an improvement over blind disassembly - at least you can see the bubbles. But the problems are equally obvious:

Inability to apply precise pressure: The pressure of manual inflation is unstable and the leak may not bubble at all.

The human eye is unreliable.: Tiny air bubbles are easy to miss and large volume products are difficult to observe fully.

Unable to simulate high waterproof ratingIPX7 requires 1 meter of water for 30 minutes without water ingress, and manual soaking simply does not meet this pressure condition.

There are no records.: It's done when it's measured, it can't be traced back, it can't be analyzed for data.

This method is not accurate enough for products that need to meet IPX7, IPX8 waterproof rating.

Ⅲ. The most common method used by engineers: airtight + real water combined leak location

This is the approach currently used by a large number of engineers, and in the end, the most direct way to find leaks is toLet the leaks show themselves.The

Airtightness TesterIndirectly determines whether a product is leaking by changes in air pressure.but (not)True Water Leak Locator is a direct view of the leak location by visualizing the bubble. This is the most reliable and efficient way to locate leaks in industry today.

Why is it reliable? Because it has:

• Fast (1 minute vs. 30 minutes with traditional methods)
• Positioning accuracy (direct visualization of bubble location)
• Repeatable (pressure parameters can be set and recorded)
• Wide application (any structure, any material, any waterproof grade)

IV. How to utilizeReal Water Leakage TesterQuickly locate the leak?

Step 1: Place the product in the clear sink

expertReal Water Leakage TesterEquipped with a clear viewing container, the product is completely submerged in water. This design is key - the clear container allows you to see where the bubbles are coming up from all angles.

Step 2: Apply pressure to create differential pressure

Three ways:

• positive pressure: Inflate and pressurize the inside of the product, the gas leaks out from the leakage point and creates bubbles, which is easy to judge visually.
• suction: Negative pressure is formed by pumping out the gas inside the product, and the outside air infiltrates inward, making micro-leakage detection more sensitive.
• hybrid pressurePositive and negative pressure synchronized or alternating loading, designed for complex multi-cavity products, exposes hidden leakage paths that cannot be detected by a single mode.

The pressure value can be set according to the waterproof rating of the product. ipx7 is usually set at a pressure value corresponding to a water depth of 1 meter and ipx8 is higher.

The higher the differential pressure, the more pronounced the bubbles. That's why real water testing is more accurate than manual soaking - the pressure is controlled and repeatable.

Step 3: Observe the position of the bubbles

This is the core aspect of the entire process.

Where the air bubbles are coming from, the leak is there.. And the bubbles behave completely differently for different levels of leakage:

degree of leakage	Bubble Characteristics	engineering judgment
slipshod	Bubbles rise continuously and rapidly, in the form of jets	Structural defects, complete seal failure
water clock used mark night watches	Bubbles are visible, stable and rising in bunches	Poor sealing, need to improve assembly process
glitch	Small, slow, episodic rise in bubbles	Material deterioration or insufficient compression force
eligible (voter etc)	bubble-free	well sealed

Take the USB port leak as an example: if you see small bubbles rising slowly and continuously at the USB port location, it means that it ismicroleakage state. It is possible that the sealing ring at the interface is deteriorated, or that there are tiny air holes in the weld joints.

This kind of precise positioning is something that the traditional blind disassembly method simply cannot do.

Step 4: Develop a targeted restoration program

Finding the leak is only the first step, what is more important is to quickly analyze the cause based on the location of the leak:

USB port leakage → Check the specification of the rubber ring, the quality of welding, and the uniformity of the sealant coating.

Shell seam leakage → Checking the snap force, screw torque, and mold accuracy.

leakage at the location of the diaphragm → Check the film bonding process and whether the adhesive backing is completely adhered.

Injection molded parts with microcracks and leaks → Check injection parameters, mold wear

Battery compartment seal leaks → Check the seal size, material, and assembly method.

With the precise location of the leak, the repair program can hit the ground running.

V. Why is true water leak localization dozens of times faster than traditional methods?

Traditional IPX7 water immersion test, the standard requirements are1 meter depth of water, 30 minutes of immersionThen take it out and check for water inside. If water is in, you'll also have to reanalyze where it's leaking.

And Precision Engineering'sAirtight water leakage tester(math.) genusLess than 1 minute from product insertion to leak location.The

This efficiency gap is a quantum leap. For production lines that need to test thousands of samples per day, time is capacity and cost.

What's more, real water testing is not only fast, it's also accurate. The traditional water immersion test can only tell you that "water is coming in", but you don't know where it's coming from. With the real water test, you can see the air bubbles directly, so you can see the leakage point at a glance.

VI. Why Jingcheng Engineering's True Water Leakage Point Instrument is widely used?

In the field of waterproof testing.Precision Engineering(used form a nominal expression)Real Water Leakage TesterAdopted by a large number of engineers for a simple reason:

Supports full grade waterproof testIPX5, IPX6, IPX7, IPX8 and even IPX9K (high pressure water jet impact test) are covered.

Flexible switching between positive and negative pressure: It can be both inflatable and vacuum tested, adapting to different product structures.

Wide range of applications: Suitable for products of different shapes and sizes to ensure test stability.

non-destructive testing: There will be no secondary damage to the product, and the product can still be used normally or continue to be improved after the test.

Data traceability: Test pressure, time, and results are recorded for quality analysis and process improvement.

These characteristics allowReal Water Leakage TesterThis applies not only to quality control but also to process validation in the R&D phase.

Summarize

When the product is hermetically sealed NG, useReal Water Leakage TesterLooking at bubbles is the fastest, most accurate, and most engineered way to locate leaks.

Benefits include:

• 1 minute to find the leakInstead of 30 minutes of guesswork.
• Visualization Bubblesand not based on empirical judgments
• Accurate pressureInstead of manually inflating
• Data traceabilitynot describing it from memory.
• Suitable for any structureInstead of being able to measure only simple products

For consumer electronics, automotive parts, medical devices, outdoor equipment and other products that require IPX7 or IPX8 waterproofing, true water leakage testing has become an indispensable part of the quality system.

If your production line is struggling to locate leaks, if your products need to achieve a high waterproof rating.Shenzhen Jingchenggongke Technology Co., Ltd.Our professional team can provide customized testing solutions and technical support.

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.