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- November 13, 2022
- PCB knowledge
- (0)
- 09 mins
Solder paste – easy and flexible method of materials assembly
What is solder paste?
The soldering method is the most reliable and flexible way to join components on a printed circuit board (PCB). To prevent short circuits on the PCB during the soldering procedure, several parameters, such as the PCB’s smooth surface and dust cleaning, must be considered before proceeding.
Experienced professionals utilize a substance called solder paste during the procedure of PCB soldering. It is a thick glue-type paste with adhesive properties. Small pieces of material are melted at the right temperature to make solder paste. Solder paste makes a strong connection between the different parts of the printed circuit board (PCB).
To successfully create solder paste, one of the most important steps is to ensure that the temperature is kept at a low level or at the appropriate level. The requirements have to be consulted in order to ascertain the precise temperature.
The use of solder paste is strongly advised for use in the process of wire bonding and bonding materials on PCBs by industry experts due to the fact that it makes it easier for electricity to flow through the circuit. It not only helps in the construction of the physical connection among materials, but it also helps in the creation of an electrical connection between the different components.
The advantages of solder paste
Solder paste has a lot of benefits that other types of soldering materials don’t have. These benefits include:
★ Quick and simple approach:
This method of applying solder paste is extremely quick and simple, and it can easily be applied even on huge surfaces in a short amount of time.
★ Lower risk of short circuits:
Solder paste makes it possible to apply a thin layer of paste, which makes it much less likely that solder bridges and short circuits will happen.
★ Possessing good flow properties
Since solder paste has a smooth surface and moves easily, it is a great way to connect parts that aren’t the same shape or are sensitive. Since it dries rapidly, it enables production cycles to be shortened.
★ Low temperament for melting:
Solder paste has the unique property of having a low melting temperature, which reduces the amount of damage done to electronic equipment and improves the longevity of electronic circuits.
★ Cartridges vertical position
If you are purchasing solder paste that comes packaged in cartridges, it is imperative that you store these cartridges in a vertical position at all times.
★ Description reading
Always make sure to check or write down the date that the soldering paste was manufactured so that you can use it before it reaches its expiration date. After the expiration date, it is no longer useful to you.
Tips of using solder paste
★ Temperature storage Level:
When making solder paste, many different kinds of materials are used, and each of these materials has its own storage temperature requirement. This is the main reason why experts say that the storage temperature should always stay between 5 and 10 degrees celsius.
★ Prepare the PCB surface to be clean:
When working with solder paste, you should always make sure that the surface you are working on is free of any dust particles. This not only helps to apply solder paste more effectively but also makes the joint between the materials last longer, which improves their endurance.
★ The technique for thawing solder paste:
After taking the solder paste out of the refrigerator, you shouldn’t open the bottle’s cap because it will quickly warm up to room temperature in four hours.
★ Tip for reuse solder paste:
After the cap of the bottle of solder paste has been opened, it is advised that you use the solder paste within 12 to 15 hours. But if you want to use it after some time, you should always clean the bottle before using it, make sure the cap is on tight, and put the solder paste in the freezer right away.
★ The amount of solder paste:
When applying the solder paste, make sure that you only use the amount of paste that is necessary and avoid applying several coatings of paste. Additionally, it can also place additional stress on the PCB surface.
The similarities and differences between solder paste and PCB flux
During the electronic assembly process, solder paste and PCB flux perform comparable functions. In both composition and function, solder paste and PCB flux have a lot of similarities and differences.Similarities
★ Active components: During the soldering process, you can make things stick better by using either solder paste or PCB flux, which are both made of active compounds. Solder paste and PCB flux also have materials that don’t do anything. These inert materials help keep the right amount of active ingredients in the material. ★ Application performed prior to soldering.
Before starting the soldering process, solder paste and PCB flux are put on the boards that will be soldered. Because of this, the active components can improve the bond before the soldering process and make sure that the joints of the material are well connected.
★ Safety and health considerations
When heated, both solder paste and PCB flux produce a lot of dangerous fumes that can be very bad for your health if you breathe them in. Heating either of these materials can also cause skin and breathing problems. Differences
★ Method of application: Solder paste is often applied using either a stencil or a jet printer. PCB flux, on the other hand, is applied straight into the lead of electronic parts. ★ The consistency of paste Solder paste’s main use is in surface-mount technology, where its thick, glue-like texture is a must. Even though PCB flux is thinner than solder paste, it is usually used in through-hole applications. ★ Timing of Implementation technique Instead of applying solder directly to the metal, PCB flux is first applied to the board’s surface. Reuse PropertyThe storage of solder paste
The storage of soldering paste is very important because it can easily affect the performance of the PCB while the materials are being joined together.
●The solder paste should be kept in a controlled storage environment that is appropriate, as recommended by the industry professionals. The ideal temperature range for creating solder paste is between 20 and 25 degrees Celsius, and the ideal humidity range for making solder paste is between 45 and 70 percent. Professionals recommend keeping the temperature of the workspace between 20 and 25 degrees Celsius.
●Although it is not required, most professionals strongly advise making use of temperature-controlled refrigerators wherever possible. A solder paste of high quality can be stored for up to six months without losing its quality.
●After the cap of the bottle of solder paste has been opened, it is advised that you use the solder paste within 12 to 15 hours. But if you want to use it after some time, you should always clean the bottle before using it, make sure the cap is on tight, and put the solder paste in the freezer right away.
●Always make sure to keep a record of each solder paste that you use, so that you can quickly apply the “first in, first out” rule to it. You will have a greater opportunity to profit from solder paste if you apply this strategy.
How to use solder paste?
During the process of applying solder paste to PCBs, there are a few stages that are highly recommended by industry professionals to be carried out.
The application of solder paste is one of the very first steps that you need to take. When you are applying it, you should always make sure that you are only applying the quantity that you require, and you should also make sure that you are only applying it to the areas where you need the joining of parts.
Even though there are a lot of different ways to apply solder paste, the methods described below are highly recommended.
By using the technique of stencil
Using a stencil, you can apply solder paste only to the parts of the circuit board that you want. First, the surface of the PCB should be cleaned, and then the stencil should be placed on the surface that has been cleaned. Apply the necessary quantity of solder paste through the stencil. If you don’t use enough solder paste through the stencil, you won’t be able to connect the joints well, and the connections are more likely to break. And on the other hand, if there is an excessive amount of solder paste, there is a risk that there will be shorts between the pads that are adjacent to one another.By using the technique of jet printer
There’s no doubt that using a stencil to apply solder paste to PCBs is a good way to do it, but sometimes even people who work in the industry have trouble following the patterns on the stencil. Also, it can be hard to figure out what the exact application requirements are on the PCB. Jet printer technology provides a solution to the problems caused by stencils. When designing the technology of the jet printer, the assembly pattern of the PCB was taken into consideration. Your jet printer will come with a prefilled cartridge; all you will need to do to use it is add solder paste to the space provided in the cartridge. Once the solder paste is in the cartridge, the software in the printer will automatically put the right amount of paste on the printed circuit board (PCB). The jet printer has significantly contributed to an increase in both functionality and flexibility.How to use silver solder paste syringes?
Using a syringe filled with silver solder paste is one of the best and most flexible methods. You have to take off the cap of the syringe, and then you have to put the needle of the syringe somewhere safe, as you will need it further.
Any kind of greasy or dusty surface affects the performance of the application and does not support a strong bond between the joints. The first thing you need to do is make sure that the surface of the PCB is clean and free of any kind of dust. This is an essential step in the process. You need to check to see if the PCB has been completely flushed before moving on. After that, check to see that no more light is leaking through the PCB’s solder joints in either direction. Continue filing until there is no longer any light coming through the connection in the wood.
After that, use the syringe to apply a little solder paste to the joints of the materials or the portion of the circuit that you want to solder. Do not be afraid to use the plunger of the syringe to apply the small amount of soldering paste that you need to put on the findings; you will become used to the amount of pressure that is required to do so.
After that, you need to remove any excess solder paste, and then you can cap the syringe. If you do this right after each use, the consistency of your silver solder paste will stay the same.
Conclusion
When solder paste is used in the soldering process, strong connections are made, electrical conductivity is increased, and the workpieces don’t rust or corrode. Soldering is an essential process when joining metal components.
But none of these goals can be reached without first choosing the right solder paste. After deciding, the next step is to apply solder paste. From there, the process moves forward based on the soldering method chosen for the last step. Before using solder paste, you should always talk to an expert if you don’t have the right knowledge and skills.
