LED lamp beads dead light causes

In the production process will always encounter a part of the lamp beads in the paste board after the test found a, a string, a few strings of lamp beads can not light up the phenomenon, for this phenomenon to make a summary:.

Welding process dead light

LED bead welding process dead light 7 major reasons.

1, the common welding method can be divided into soldering iron welding, heating platform welding and reflow soldering, etc.: A, soldering iron is the most common soldering process.

A, soldering iron soldering is the most common, such as making samples, maintenance, as most existing manufacturers in order to save costs, the purchase of the soldering iron is mostly substandard slightly quality products, mostly poor grounding, there is leakage, the welding process which is equivalent to the leakage in the tip of the soldering iron - be soldered LED - human body - the earth to form a circuit, that is, equal to tens of times - hundreds of times the voltage applied to the beads LED lamp beads above, instantly burn it out.

Note: The situation will be more serious when the body is connected to the electrostatic band, because when the human body is connected to the earth to form a circuit of resistance is smaller, the current through the human body to the lamp beads will be greater, which is also a lot of people say that there is clearly with the electrostatic band or so many lamp beads damaged problem.

B, heating platform welding caused by dead lights, due to the constant sample of lamps and lanterns, most companies in order to meet the needs of small quantities and sample orders, due to the low cost of equipment, structure and simple operation and other advantages, heating platform has become the best production tools, but, due to the use of the environment (for example: there are fans where the temperature can not be constant problem) and welding operators to operate the degree of proficiency and control of welding speed on The larger problem caused by the dead light, in addition to the heating platform is the equipment grounding situation.

C, reflow soldering, generally this type of welding is the most reliable production method, suitable for mass production processing, if not properly operated, will cause more serious consequences of dead lights, for example, unreasonable temperature adjustment, poor grounding of the machine.

2, improper storage caused by dead lights.

This problem is the most common, due to the opening of the package does not pay attention to moisture problems, due to the sealing of the lamp beads more silicone materials, which according to a certain water absorption characteristics, after the damp lamp beads paste board, after the high temperature welding process silicone will be thermal expansion and contraction, gold line, chip, bracket deformation resulting in gold line displacement fracture, the light point does not light phenomenon, so it is recommended: LED to be stored in a dry and ventilated environment. Storage temperature of -40 ℃ - +100 ℃, relative humidity at 85% or less; LED in its original packaging conditions within 3 months of use is better to avoid rusting bracket; when the LED bag opened, to use up as soon as possible, at this time the storage temperature of 5 ℃ -30 ℃, relative humidity at 60% or less.

3, chemical cleaning.

Do not use unknown chemical liquid cleaning LED, because that may damage the surface of the LED colloid, or even cause cracks in the colloid, if necessary, please use alcohol swabs for cleaning in room temperature ventilation environment, the time is best controlled in a minute wind to complete.

4, deformation caused by dead lights.

As some of the light board deformation exists, the operator will go to plastic, due to the board deformation, the lamp beads above also followed by the same time deformation, pulling off the gold line, to the light does not light, it is recommended that there is this type of board is best to plastic processing before production. Longer in the production of assembly and moving over and may also cause deformation pull off the gold line phenomenon. There is also the stacking caused by the production process for convenience and smoothness, the light board will be stacked randomly, due to gravity, the lower layer of the lamp beads will be deformed by the force, damage to the gold line.

5, heat dissipation structure, power supply and light board do not match.

Due to unreasonable power supply design or selection, the power supply exceeds the maximum limit that LED can withstand (super current, instant impact); unreasonable heat dissipation structure of the lamps and lanterns, will cause dead lights and premature light decay.

6, factory grounding.

Must check whether the total grounding line of the factory is good.

7, static electricity.

Static electricity can cause LED function failure, it is recommended to prevent ESD damage LED.

A, LED testing and assembly operations personnel must bring anti-static hand ring and anti-static gloves.

B, welding equipment and test equipment, work tables, storage racks, etc. must be well grounded.

C, the use of ion fans to eliminate the LED in storage and assembly during the electrostatic generated by friction.

D, the LED box using anti-static boxes, bags using static bags.

E, do not exist a fluke, touching the LED with your hands.

LED damaged by ESD will appear abnormal phenomena are.

A, reverse leakage, the lighter will cause a reduction in brightness, the more serious lights do not light.

B. Downward voltage value becomes small. LED can not light when driven by low current.

C, poor welding caused by the light point does not light.