Airtightness tester NG parts test qualified? Reveal the influence of temperature on the test

In industrial production.Air tightness test is like a "rigorous physical examination" of the product to distinguish between OK and NG products. Every non-conforming (NG) product can mean huge economic losses and potential safety hazards.

Today, let's take a look at why some seemingly failed products may end up passing the airtightness test.

I. Ambient temperature: the "invisible mastermind" affecting test results

1. The basic principle of airtightness testing

To figure this out, we have to understand a basic principle. In physics, there is a formula called the 'ideal gas equation of state':

PV = nRT

To put it bluntly:

• P is pressure.
• V is the volume (test volume)
• n is the amount of gas - R is the ideal gas constant (8.314 J/(mol-K))
• T is the temperature

This formula tells us that temperature changes directly affect the test results. 

2. How temperature changes can "mess things up"

想象一下，Airtightness testing equipment就像一位精密的「侦探」，负责检查产品是否存在微小的空气泄漏。但这位「侦探」可能会被环境温度「迷惑」，导致判断出现偏差。The study found that small changes in temperature could make test results 'unreliable'.

3. Real-life case sharing

Recently, an engineer who is a fan of Precision Engineering's airtightness encountered an interesting situation:When using a well-known brand of instrument for airtightness testing, the product that was originally judged to be unqualified (NG) surprisingly passed the test in the end, and the airtightness test showed a pass.

After repeated troubleshooting, they found that the culprit of the problem was most likely the drop in ambient temperature and the low temperature of the workpiece. Our advice to him was:气密性检测作业时尽量在恒温车间使用，目前大部分品牌的Airtightness Tester都有这种缺陷。

II. Deeper causes of miscarriage of justice due to temperature changes

We've already learned the basics of the relationship between temperature and airtightness testing. Now, let's take a closer look at how temperature variations can affect test results and how to effectively circumvent these misjudgments.

1. Importance of constant temperature of workpieces

The temperature of the workpiece is a key factor affecting the accuracy of gas tightness testing. The state of motion of gas molecules changes significantly at different temperatures:

• The higher the temperature, the more violent the movement of gas molecules and the greater the distance between molecules
• The lower the temperature, the slower the motion of the gas molecules and the smaller the distance between the molecules

This means that the pressure and leakage characteristics of the same volume of gas can change under different temperature conditions. Therefore, it is critical to keep the workpiece in a stable temperature environment.

2. Criticality of ambient temperature control

Fluctuations in ambient temperature can directly affect the reliability of test results. The ideal environment for airtightness testing should have the following characteristics:

• Constant temperature within ±1°C fluctuation range
• Selection of an enclosed, temperature-controlled testing environment

3. Hidden hazards of airflow fluctuations

Seemingly insignificant changes in airflow may actually seriously interfere with airtightness testing:

• Temperature gradient near air conditioning vents
• Vortexing of airflow from internal shop fans blowing directly into the inspection area

All of these factors mayThis leads to unstable and unreliable test data, which deviates greatly from the actual leakage data, resulting in the misjudgment phenomenon of passing the airtightness test of NG parts.

III. Precise control: an effective strategy to eliminate temperature misjudgment

1. Selection of high-end testing equipment

• With real-time temperature monitoring function
• Automatic temperature compensation

2. Establishment of a standardized testing process

• Establishment of strict ambient temperature control standards
• Setting a fixed workpiece preheating/precooling time
• Equipped with specialized temperature monitoring and control equipment

3. Periodic calibration and maintenance

• Quarterly calibration of instrument accuracy
• Record and analyze the effect of temperature changes on test results
• Timely updating of testing standards and parameters

IV. Practice Case: Precision Engineering's Temperature Compensation Solution

JC Seriesairtightness tester不仅提供了先进的温度补偿技术，还针对不同行业的特殊需求，提供了量身定制的解决方案：

• Automotive Parts Seal Inspection
• Electronic component air tightness test
• Medical Device Seal Evaluation
• Aerospace component inspection

V. Summary

Temperature may seem insignificant, but in hermeticity testing it can make the difference between life and death for a product. By deeply understanding the mechanism of temperature influence, adopting advanced compensation technology, and performing airtightness operations in a constant temperature and humidity environment, we can dramatically improve the accuracy and reliability of testing.

Precision Engineering will continue to commit to the innovation of airtightness testing technology to provide customers with more accurate and reliable solutions. Let us together, with the wisdom of science and technology, for product quality protection.