Gas tightness detection method for car headlights

Key words: tightness detection, leak detector, headlight sealing

Why should a car light detect its air tightness? Because the car lights, such as tight seal, when it comes to rain, the lights will enter the water, the light bulb will burst in the case of hot water, so the manufacturer needs to detect the air tightness of the lamp.

The leak detection device for air tightness is divided into positive pressure test and negative pressure test in the automobile lamp industry.

1. Positive pressure test

1, the so-called positive pressure, that is, according to the requirements of the industry and products, the workpiece is connected with the fixture seal to connect gas source and air tightness leak detector, set a certain standard value and beat, fill a certain pressure of gas into the workpiece, so as to judge whether the workpiece is qualified.

2. Products tested: headlamp, tail lamp, turn signal, license plate lamp assembly and headlamp shell.

3, we chose the A601 air leak detector produced by Hefei Yuan Zhi Automation Technology Co., Ltd. to test the headlights. The minimum detection accuracy of the A601 type leak detector can achieve the accuracy of 1Pa. The differential pressure sensor with a range of 2000Pa is adopted, and the stability is good.

4, the vehicle lamp detection parameters are as follows:

A, pressure: generally between 15-20KPa, if the pressure is too large or too small, the workpiece is easy to deform or fail to detect results.

B, inner volume: the inner volume of the car piece is generally less than 2L, the bus light may be larger, the smaller the content, the shorter the inflation time, the faster the detection.

C, beat: that is, the time spent on the test, usually about 28 seconds, including 10 seconds of inflation, 10 seconds of balance, 5 seconds of detection, and 3 seconds of deflation.

D, leakage rate: that is, according to the standard set by the manufacturer's requirements, if most manufacturers ask for 30Pa, the test results are less than 30Pa, and the 30Pa is not qualified, and the other manufacturers use the flow to judge the amount of the leakage of the workpiece.

5. Test results

50 large lamps were detected, and the same product was repeated for 30 minutes each interval. The data was compared and the data of the same product was detected. The maximum and minimum difference was 1.8pa, and the maximum difference was small. Compared with the equipment used earlier by the customer, the maximum difference was reduced by 5pa, and the accuracy of the detection was greatly improved.