LED lamp bead welding process dead lamp reason

In the production process will always encounter part of the lamp beads in the post-mortem test found that there is a string, a few strings of lamp beads can not be lit phenomenon, to be a summary of this phenomenon:

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Dead lights during welding

1, common welding methods can be divided into electric iron welding, heating platform welding and reflow soldering, etc.:

A, the most common electric soldering iron, such as doing the same kind, maintenance, as most of the existing manufacturers in order to save costs, buy back the electric soldering iron mostly unqualified slightly products, most of the ground is poor, there is leakage situation, the welding process This is equivalent to leakage in the tip of the iron - was welding LED - the human body - the earth to form a loop, that is equal to several times - hundreds of times the lamp withstand voltage applied to the LED lamp above the moment Burn it out. Note: The static belt will be more serious, because when the human body after the electrostatic belt formed loop smaller resistance through the body to the lamp current will be greater, which is what many people said clearly with static electricity Belt or there are so many problems with lamp beads damaged.

B, heating plate welding death lamp, the lamps and lanterns as a single sample constantly, most companies in order to meet the needs of small batch and sample list, due to the low cost of equipment, structure and simple operation, the heating platform has become the best production tools However, due to the use of the environment (such as: there is a fan where the temperature can not be constant problem) and the welding operator proficiency and welding speed control has become a cause of the death of a larger problem, in addition to heating Platform equipment grounding situation.

C, reflow, the general welding method is the most reliable method of production, suitable for mass production and processing, if improper operation, will result in more serious consequences of dead lights, such as temperature adjustment unreasonable, bad grounding and other machines.

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2, caused by improper storage of dead lights:

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This problem is the most common, due to not pay attention to moisture after opening the package, the use of silicone beads light plastic materials, which according to a certain water absorption characteristics, damp beads after board, after high-temperature welding process Silicone will be thermal expansion and contraction, the gold wire, chip, stent deformation caused by the displacement of the gold line breaks, the light does not light the phenomenon produced, it is recommended: LED should be stored in a dry and ventilated environment, the storage temperature is -40 ℃ - +100 ℃, relative humidity below 85%; LED in its original packaging conditions used within 3 months is better to avoid rusting stent; when the LED package opened, as soon as possible to use this When the storage temperature is 5 ℃ -30 ℃, relative humidity below 60%.

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3, chemical cleaning:

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Do not use unclear chemical liquid cleaning LED, because that may damage the LED colloid surface, or even cause colloidal cracks, if necessary, please use an alcohol swab at room temperature ventilation environment for cleaning, the best time to complete control in one minute of wind.

4, deformation caused by dead lights:

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As part of the light board deformation exists, the operator will go to plastic, due to deformation of the board, the above lamp beads also followed along with the deformation, pull off the gold line, the light does not shine, it is recommended that this type of board Fortunately, plastic surgery before production. Longer in the production assembly and moving too and may also cause deformation pull off the gold wire phenomenon. There is stacked cause, the production process for the convenience of smoothly, the light board stacked randomly, due to gravity, the lower lamp beads will be deformed by force, damage the gold line.

5, cooling structure, power and light board does not match:

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Due to unreasonable power supply design or selection, the power exceeds the maximum limit LED can withstand (overcurrent, instantaneous impact); lamps cooling structure is irrational, can cause dead lights and premature decay

6, the factory ground:

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You must check the factory's total ground connection is good.

7, static electricity:

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

A, LED testing and assembly workers must bring anti-static bracelet and anti-static gloves.

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

C, the use of ion fan to eliminate LED static electricity generated by friction during storage and assembly.

D, equipped with LED boxes using anti-static material boxes, bags using electrostatic bags.

E, do not be lucky, readily touch the LED.

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Anomalies that can occur with ESD-damaged LEDs include:

A, the reverse leakage, the light will cause reduced brightness, serious light does not light.

B, the forward voltage becomes smaller. The LED can not emit light when driven with low current.

8, poor lighting caused by light does not light.