Highway LED Variable Speed Limit Sign Environmental Test Specification

Friends who drive often know that there will be many LED speed limit signs on highways. The quality of these LED products exposed to the outside is easily affected by the environment, so we have to conduct environmental tests on them. The following is highway LEDs Test Specification.

Equipment needed: constant temperature and humidity test chamber, thermal shock test chamber, vibration table, smoke test machine, xenon lamp weather test machine

1. Low temperature resistance performance: When the product is not energized, set the constant temperature and humidity test chamber at -20°C (or -40°C, -55°C) and test for 8 hours. The product should start normally and the logic is correct.

2. High temperature resistance performance: When the product is not energized, adjust the temperature of the constant temperature and humidity test chamber at 55°C (or 50°C, 45°C) and test for 8 hours. The product should start normally and the logic is correct.

3. Humidity and heat resistance: When the product is not energized, set the constant temperature and humidity chamber temperature at 40°C and relative humidity (98±2)%, and test for 48 hours. The product should start normally and the logic is correct.

4. Temperature resistance performance: Put the product (modules representing product quality characteristics can be used when the conditions are limited) into a thermal shock test chamber under the energized working state, keep it at a high temperature of 70°C for 2 hours, and transfer to a low temperature within 3 minutes Keep it at -40°C for 2 hours, then transfer to high temperature within 3 minutes, and circulate five times in this way.

During and after the test, the product should start up normally and the logic is correct; the structural parts of the product, including pixels, printed circuit boards, display modules, racks, display screens, etc., should not be deformed or damaged.

5. Mechanical vibration resistance performance: The product is subjected to a sweep frequency vibration test under the energized working state, and the frequency range is 2Hz～150Hz. According to the positioning control at 2Hz～9Hz, the displacement amplitude is 3.5mm; at 9Hz～150Hz, according to the constant acceleration control, the acceleration amplitude is 10m/s². 2Hz→9Hz→150Hz→9Hz→2Hz is a cycle. After a total of 20 cycles, the product functions normally, the structure is not affected, and the parts are not loose.

6. Salt spray corrosion resistance: the printed circuit board, the outer shell anti-corrosion layer and the pixel and its supporting bottom plate (other parts are agreed by the supplier and the buyer) after the 168 hours salt spray test, there should be no obvious rust phenomenon, and the metal components should be no red rust spots, the printed circuit board will function normally after 24 hours of natural drying.

7. Weather resistance: The appearance of the product's shell anti-corrosion layer, pixel and its supporting bottom plate (other parts are agreed between the supplier and the buyer) after two years of natural exposure test or artificial accelerated aging test, the cumulative energy of the product reaches 3.5*10^6KJ/m² There should be no obvious aging phenomena such as fading, chalking, cracking, dissolution, rusting, etc. The retention rate of mechanical properties of non-metallic materials should be greater than 90%, and the chromaticity coordinates should meet relevant requirements.

For highway LED variable speed limit signs, only after the above-mentioned tests are completed and passed, can this product be qualified. If you have any questions about product testing, you can also consult us to understand the specific testing process of the product.