LED SMT & DIP

LED SMT & DIP

  As we know, PCB board and driver are the most important part in LED light which finished in SMT and DIP workshop.Therefore, the materials in this process and the control of the process will undoubtedly decide the price and quality of an LED light.Then why this same process make such a huge difference?
     Lets follow the process of LED SMT & DIP.

SMT

PCB：
    As the carrier of LED driver and SMD ,the choice of PCB board is much more important.There are many kinds of PCB boards in the market based on different quality and price, such as FR-4, copper base printed board, aluminum base printed board, iron base printed board, ceramic base printed board and so on.According to several years testing and under our experience,aluminum PCB board almost can satisfy the basis requirements except COB type.And the power supply can be used with single or double-sided fiberboard.But there still will be big different for the price based on different material,the thickness of the board,the thickness of the surface copper foil and other Various processing standards.

Brush the solder paste:
    Solder paste is the adhesive of SMD and PCB and every factory provide different material ,price and characteristics .Then which one is much more suitable?
    1. Melt forming temperature of solder paste
     Melt forming temperature divided into high temperature,low temperature and ultralow temperature.As we know that SMD components have a limited tolerance for temperature,take LED SMD for example,we suggest don’t exceed 200℃.That’s why we need pay attention to the melt forming temperature.Elegent light have tested long time and final found the suitable solder paste.
    2. Silver content of solder paste
     Why silver needed in the solder paste? And not less than 1.5%? because silver has good malleability, thermal conductivity, conductivity.Good malleability ensures that solder joints don't crack easily.In other words,inside SMD won’t easily break away from PCB board when the light is subjected to a strong mechanical force.As for its thermal conductivity and conductive properties, the total content of silver in the paste is not high, so the effect is limited.
     Except the component,The thickness, size and shape of the solder paste on PCB will affect the quality and price of LED lights.

SMT：
    SMT is now mostly done by SMT machine.For LED lights, normally don’t use SMT electronic material smaller than 0402 .So it is not too high accuracy requirements for SMT machines. But the efficiency of the SMT will affect the price of the LED light.Such as the LED tube which needed many leds.The difference of theoretical speed between 50,000-60,000 dots/hour and 110,000 dots/hour we can totally imagine. And how to properly match the SMT equipment to make the SMT more efficient, that is also worthy of being studied by engineers.For the details which we have offered better solution in our site:www.elegentlight.com/art/manufacturer-11.html.

Reflow:
    Reflow soldering is a process that melts the solder paste on the PCB at high temperature and condenses at low temperatures.Standard reflow is long reflow soldering, but now many factories use short reflow to save cost, which causes the solder paste not to be fully heated, resulting in many quality problems.

DIP

DIP：

     DIP is an important part of LED power supply. and the quality of the DIP electronic material can have a fatal effect on the performance of the whole light. Anyone who has used LED light will got to know the quality of driver also will largely affect the life of LED light.
     Except the materials are different ,the process of DIP also will affect driver production.
     
     Above two photos are the most popular process for DIP, we should be able to see the difference between this two process.

Testing:
    Testing is a key step in detecting PCB board and power performance.Its simple for the testing of LED PCB board,just light the lamp with DC power, there is no much different from other factories.But its quite different for LED power supply testing,the difference here is mainly reflected in the test efficiency.Many factories will show to customers that they can test more than 20 pcs PCB board one time and they thought its high efficiency with low cost .also its fact.But the power test is not just efficient.People who have tested LED know that it takes 10 to 15 minutes for the lights to be energized, and the entire lamp's performance can be stabilized because it needs to reach a thermal equilibrium.Same theory as power supply,Not to say that the power supply itself needs to achieve thermal equilibrium, but it should achieve electrical stability.It need time around 2-3s, too fast tests can’t actually test the electrical properties of the power supply.
   
Aging:
     Aging test is the most important process .The quality of a factory that does not have Burn-In Room is absolutely unwarrantable.Then why aging is so important ?
     We all know that there are so many electronic material including LED SMD at least a few dozen, some two or three hundred.we can’t test one by one.but if one of them damage or fail,it will affect whole light.Then aging test is the most effective way to test these electronic materials.
     Aging is divided into static aging and dynamic aging.many people will say aging workshop is available and products are reliable.But you will find many of them are static aging which is just lighting under stable voltage.The test does have some effect, but it has a limited effect.Because the voltage is always changing under actual using.In some places with good infrastructure, the voltage is stable and the fluctuations are small, and the performance requirements of the lamps are less stringent.But in many places, bad local electricity environment together with greatly fluctuated voltage, this is very strict to the lamp compatibility requirement. Now you can image static aging is not enough,then how to do ?
     Dynamic aging can solve this problem in some degree.Dynamic aging is a simple simulation of actual usage, so dynamic aging is necessary to ensure the quality of LED light.
     Except aging test aging equipment ,aging time also is important.then how long it is suitable? There is no exact answer. Take example for Elegent light, every new product comes out and we're going to do an aging tracking test,make record to the quantity of defective products in every 1 hour until no defective product or yield achieve for 4 consecutive hours.This makes aging time based on data.
     Aging is an important step in detecting the stability of LED products, but many factories are struggling to cut down the cost of electricity and aging equipment and resulting in many undesirable products.
   
     Leds are in the increasingly fierce competition but price is lower and lower .Many factories cut down the cost of material and production process. This lead to make the LED quality worse and worse, how to effectively balance the cost and quality?This deserves further study.

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