These days, a wide range of electronic devices comprise SMD components, these include the SMD chip or ICs. Therefore, it is very important to know how to remove these SMD components from printed circuit boards or electronic devices. You will need to remove SMDs when there is a need for repair or replacement.
There are many ways you can remove an SMD chip. In some cases, a hot air station can carry out some solder jobs a soldering iron can’t. The hot air rework stations make use of hot air to desolder or solder an SMD component. Our discussion in this article will focus on how to remove an SMD chip with hot air.
How to Use Hot Air to remove an SMD Chip
It is always advisable to practice on an old circuit board if it is your first time removing SMD components with hot air. You can use a new board when you have already acquired the necessary knowledge and skills.
In some cases, you won’t know the solder has gotten to a molten state since there little solder is used for soldering the components.
Typically, the melting point of a lead-free solder is usually about 217°C. Therefore, you need to ensure the pads and leads are up to the required temperature before you remove the SMD component. You will need a higher temperature since the solder joints needs to reach the melting point quickly.
In cases whereby the temperature of the hot air gun is lower, the solder joints won’t get to the melting point on quickly. The temperature of the component will increase if it takes a longer time to increase the pads or leads’ temperature. Therefore, it is much better to heat the component, remove it and the hot air gun. The part can be placed in a good environment to cool off.
One important thing PCB assemblers need to understand is to always treat their oxidized solder joints by using leaded solder. Do this before you begin with the hot air stage. Also, preheat the circuit board to 200 degrees Celsius after the process of mixing the solder. You can then continue to use the hot air station.
Why Hot Air is used for Soldering and Desoldering SMDs
Hot air is usually used during soldering and desoldering of SMDs. You can also use it for repair work. Even sometimes, you can use it to recycle the components of mobile phone and your PCs. Engineers easily use a hot air blower to remove electronic components from PCBs. Also, metal parts can be desoldered without using a soldering iron.
When using hot air to desolder SMDs, heat up the soldering joint with hot air and warm up solder, after this, the components will carefully detach. Hot air can help you save some time as well as existing parts that you might consider trashing with the circuit board.
Sometimes, a hot-air rework station can act as a soldering station. This reveals a lot as you can desolder a resistor and solder another one. Hot-air is great for getting rid of SMD chips, especially multi-pin ICs. Over time, hot air has proved to be very efficient in desoldering PCB components. But, engineers and designers have to be completely sure they put certain things in place. For instance, the nozzle’s size, air flow, and temperature of the hot air must be accurate.
Things to Watch out for When Removing SMD Chip with Hot Air
Detaching SMD chip by integrating hot air requires careful attention. This is because there are some errors that are likely to be made during this process. This is why you should ensure your tools are readily available. Below are some of the things you must consider:
The tools must be right for the job and must be available
To ensure the process goes smoothly, you need to work with the right tools. It involves a reliable soldering iron, soldering flux, desoldering braids, as well as heat gun. The whole process can be easy for you whenever you are working with the right tools. In addition, there is a low chance that any damage will happen to your SMD integrated circuit as well as the other components of the printed circuit board.
The temperature level
During heat exposure, SMD components become highly vulnerable and for extreme heat, the SMD chips could be completely destroyed. This is why it is advisable users take note of the temperature level they are making use of
Careful cleaning
Immediately you are done taking out the old solder, you have to clean the dirts found inside the chip. One tool that is very important here is the soldering flux.Proper cleaning will help the new component attach firmly to the board.
Testing
It is important to always carry out tests when you remove SMD chips with hot air. Errors could occur during this process and early detection could help to prevent further damage. Therefore ensure you test your components.
Possible Consequences of Using too High Temperature.
The application of hot air to remove SMD components usually require a level of temperature. If the temperature used is more than the required temperature level, some damages could occur. So, what are the possible consequences of setting a high temperature.
Component damage
When the temperature is set too high, it can cause serious damage to the SMD chips including other components like resistors and capacitors. This may result in failure or malfunction.
Toxic fumes
When the temperature is extremely high, the solder and flux can produce toxic fumes which is poisonous to humans and their environment. Therefore, we recommend engineers to work in an environment that is well-ventilated. Also, they should wear protective gear for safety purposes.
Too much solder flow
There could be too much flow of solder when the temperature is extremely high. This can lead to problems like cold joints and short circuits. These problems can make a circuit malfunction.
Advantages of Hot-Air Rework Station
Fast and Safe
Engineers who carry out repair work on electronic devices know the importance of hot air rework stations. Using hot air for your rework helps you to easily solder and remove any SMD components without mistakes. The hot air reworking method offers a high level of accuracy. Therefore, this makes it easy to easily remove any faulty electronic components form a circuit board. Also, you can easily install a new component in a twinkle of an eye.
Moreso, your hot-air gun’s nozzle shouldn’t come in contact with the boards. Therefore, these aspects reduce any possible damage to other parts of the board that could be caused by overheating.
Multiple functionalities
Since hot-air rework stations serve different functionalities, you can use them as primary soldering stations. This is a preferred way of removing SMD chips from electronic boards. There are other hot-air soldering station versions that offer more functions like screen printing for reattachment reflow. Also, these stations are accurate and very convenient to use.
What is the Ideal Temperature for Removing SMD Chips?
SMD chips are usually small in size. A good amount of heat is needed to detach these components from a board. This is the major reason you should make use of the required temperature. If the temperature is okay, you will do away with the solder. But you need to know that, no particular amount of temperature is ideal since this all depends on some factors.
For instance, the melting point of a leaded solder is less when compared to a solder that is lead free. This is why you need to use a lower temperature when trying to remove any SMD component. Furthermore, when taking out the SMD chip with the hot air, place the temperature within the 350 to 380 degrees centigrade range.
How Can You Use the Hot Air Rework Station?
It is very important to handle hot air tools properly. This helps in preventing the falling of the tool. With the guidelines we have highlighted below, you should be able to utilize the hot air tool effectively.
- To make sure there’s stability, hold this tool firmly. Make sure your skin doesn’t touch its hot part
- Make sure this tool is higher than the part to be soldered. Heat up this area using the circular motion
- Place small quantity of solder on the end of each wire and then ensurefree flow over the track. The solder must look like the shape of a volcano.
- Take away the hot air when the whole process has been completed. Allow the board to cool before moving it.
- Confirm the joint to see if it has a volcano shape. You can as well put more solder on it. Before adding more solder, ensure the lead and track have gone through proper heating.
Conclusion
SMD chips are vital components and it can be a daunting process to remove them from a PCB or electronic device. The best way to bring out these chips is to use hot air. Hot air can also get rid of other SMD components like transistors and resistors.
