Posts Tagged ‘SMT’

5 Benefits of Putting Nitrogen into Reflow Oven

星期一, 7 1 月, 2019

The reflow oven is one of the indispensable equipments in SMT. Putting the PCB with components goes through the reflow oven then the solder paste adhering on the printed circuit board will melt. After the solder paste getting cold, the components will adhere to the PCB stably.

Picture of reflow oven

After you have learned something about reflow oven, have you ever know how to make the reflow oven work better? Here are 3 benefits of putting nitrogen into reflow oven listed as following:

âˆšÂ It is able to make the surface tension of solder paste get smaller which is good for the components adhering to the PCB more easily.

âˆšÂ It can decrease the oxidization in a certain. Because the nitrogen is a kind of inert gas which is hard to produce chemical compound.

âˆšÂ Reducing the rate of void. Because the rate of void decreases with oxidation.

âˆšÂ Nowadays, some manufacturers also develop to put nitrogen in wave soldering oven. It is able to decrease the speed of oxidation of liquid tin in the bath. As the slag of tin will be formed when the liquid tin contacts with air. After that, the slag of tin will adhere on the printed circuit board. If it happens to the connect between two spots of tin, it will cause short circuit.

âˆšÂ It can increase the rate of tin feeding of pin components and then they will combine with the printed circuit board firmly.

PCB with components

Best Technology,Â a professionalÂ PCBÂ solution provider, is always dedicated to catch up with times. Our unique technology and high quality products will give you a competitive supply of printed circuit boardÂ and PCB assembly and make your wearable devices more excellent. To learn more, contact us at 0755-29091601 or check our website: https://www.bestpcbs.com

The component mounting requires high precision of equipment and the common defects including forgetting to mount the component, mounting the component in a wrong way, polarity reversal etc.. AOI technology not only can find the defects above, but also can check the connection dense spacing and the solder paste on the pads of BGA component.

Since the component mounting is followed by the reflow soldering, the testing after component mounting is usually called front end inspection of reflow soldering. However, it is meaningless from the perspective of quality guarantee. Because the defects can not be found in the reflow oven. The solder tin is able to correct by itself after melting in the reflow oven, so the the mounting displacement and solder printing status can not be detected on the substrate after soldering. In fact, the front end inspection of reflow soldering is incredible significant for quality guarantee as that the component mounting of all parts can be inspected before reflow soldering.

The alarm will be sent out if the defects are found by AOI technology. After that, the visual inspection will be carried out by the operator. If miss some components at this stage, it can be corrected by tweezers. After the visual inspection operator repaired the same problem for many times, he will ask the person who charge the production equipment to reconfirm whether the setting of the machine is reasonable. The feedback information is very helpful to enhance the production quality and it can improve it in a very short time.

In our circuit board manufacturing workshop, we have professional equipment to do that testing. But normally these equipment was expensive, and a lot of people want to know a simple and cheap way to do that solderability testing, so today we are doing a simple solderability test and show you all the steps.

1. Take a small solder pot, plug in the power, turn on the switch and heat the solder pot to a certain high temperature(about 8 minutes).
solder-pot
2. Put a tin bar to the solder pot, then you can see the tin bar is begin to melting, slowly into liquid tin, then more and more.

Tin Bar

3. After few minutes, there will be enough melting liquid tin in the solder pot to do this test.

melting-tin

4.Use a tweezers to pick up a PCB circuit, first clean the PCB with rubbing alcohol. Because the unclear surface or the oxidation of the PCB will affect the test result. Pick-up-the-PCB
5. This is the key step of this test, put the PCB into the solder pot, depth about 2 mm,time 4-5 seconds is ok. Then you can see the tin will go into the hole of the PCB.

Solderability Test 1

Solderability Test 2

6. Take out the PCB from the solder pot and put it into the cold water. After few seconds, you can see the experimental effect.

Test Results

This solderability test is very simple and easy. We can see the results very soon. We,Â Best Technology did solderability of every batch PCB we made, and we also supply our customers with the solderability test report and the test samples.

Any comments about that, leave your message or write email to us. Best Technology, always to be your best partner of circuit boards in China!

Posts Tagged ‘SMT’

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