1. Welding type
Generally, welding can be divided into three types: electric soldering iron welding, heating platform welding and reflow soldering welding:
a: The most common method is electric soldering, such as shaping and repairing electronic components. Nowadays, LED manufacturers, in order to save their production costs, mostly use counterfeit and shoddy electric soldering irons, resulting in poor contact and sometimes leakage. During the welding process, this is equivalent to forming a circuit between the leaking soldering iron tip - the soldered LED - the human body - and the earth, That is to say, the voltage that is tens to hundreds of times greater than the voltage borne by the lamp beads is applied to the LED lamp beads, instantly burning them out.
b: The dead light caused by welding on the heating platform has become the best production tool for most enterprises in order to meet the needs of small batches and sample orders due to the continuous number of lamp sample orders. Due to the advantages of low equipment cost, simple structure and operation, the heating platform has become the best production tool, Due to the use environment (such as the problem of temperature instability in areas with fans), the proficiency of welding operators, and the control of welding speed, there is a significant problem of dead lights. Additionally, there is the grounding of the heating platform equipment.
c: Reflow soldering is generally the most reliable production method, which is suitable for mass production and processing. If the operation is improper, it will cause more serious dead light consequences, such as unreasonable temperature adjustment, poor machine grounding, etc.
2.Storage environment causing dead lights
This often happens. When we open the package, we don't pay attention to moisture-proof measures. Most of the lamp beads on the market now are sealed with silica gel. This material will absorb water. Once the lamp beads are affected with moisture, the silica gel will thermal expansion after high temperature welding. The gold wire, chip and bracket will be deformed, causing displacement and fracture of the gold wire, and the light spot will not be lit, Therefore, it is recommended to store LEDs in a dry and ventilated environment, with a storage temperature of -40 ℃ -+100 ℃ and a relative humidity of less than 85%; It is recommended to use the LED in its original packaging condition within 3 months to avoid rusting of the bracket; After the LED packaging bag is opened, it should be used up as soon as possible. At this time, the storage temperature is 5 ℃ -30 ℃, and the relative humidity is below 60%.
3. Chemical cleaning
Do not use unknown chemical liquids to clean LED, as it may damage the surface of LED colloid and even cause colloid cracks. If necessary, please clean with an alcohol swab in a room temperature and ventilated environment, preferably within one minute of wind completion.
4. Deformation causing dead light
Due to the deformation of some light panels, operators will undergo plastic surgery. As the panels deform, the light beads on them also deform together, breaking the gold wire and causing the lights to not light up. It is recommended to perform plastic surgery before production for this type of panel. Long assembly and handling during production may also cause deformation and breakage of the gold wire. Also, it is caused by stacking. In order to facilitate the production process, the lamp panels are randomly stacked. Due to gravity, the lower layer of lamp beads will be deformed and damage the gold wire.
5. The heat dissipation structure, power supply, and lamp board do not match
Due to improper power supply design or selection, the power supply exceeds the maximum limit that the LED can withstand (over current, instantaneous impact); The unreasonable heat dissipation structure of lighting fixtures can cause dead lights and premature light decay.
6. Factory grounding
It is necessary to check whether the overall grounding wire of the factory is in good condition
7. Static electricity
Static electricity can cause LED function failure, and it is recommended to prevent ESD from damaging the LED.
A. During LED testing and assembly, operators must wear anti-static bracelets and anti-static gloves.
B. Welding and testing equipment, work tables, storage racks, etc. must be well grounded.
C. Use an ion blower to eliminate static electricity generated by friction during LED storage and assembly.
D. The material box for installing LED adopts anti-static material box, and the packaging bag adopts electrostatic bag.
E. Don't have a fluke mentality and touch the LED casually.
The abnormal phenomena that LED damage caused by ESD include:
A. Reverse leakage may cause a decrease in brightness in mild cases, and the light may not turn on in severe cases.
B. The forward voltage value decreases. LED cannot emit light when driven by low current.
C. Poor welding caused the lamp to not light up.
Post time: May-15-2023
