Printed Circuit Boards (PCBs) are found in all sorts of devices, from cellphones to computers. PCB assembly is a complex and precise process that must be done with the utmost accuracy if the device is to function properly.  The assembly includes but is not limited to the attachment of integrated circuits, capacitors, resistors, diodes, and transistors. This process typically starts with the placement of the smallest components on the PCB’s surface pads. Once those parts are in place, larger and more complex components can be added. In most cases, the final assembly occurs in a factory environment where workers use highly specialized tools and equipment to get the job done quickly and accurately, but we can offer final assembly solutions with our expertise and skill. There are a number of steps involved in this entire PCB assembly process, and this post discusses one of the most crucial steps; PCB soldering.

What is PCB Soldering?

Soldering is the process of joining two metals by melting a filler metal in between them. The most common use of soldering is to join electrical components to a printed circuit board (PCB). The main purpose of soldering is to create a strong and reliable electrical connection. There are many reasons why proper soldering is a must. Poorly soldered joints can cause short circuits, heat damage, and signal interference.

Main PCB Soldering Techniques

The best way to ensure a good solder joint is to use the right tools and follow the proper soldering techniques. The most commonly used techniques are:

  • Wave Soldering: Wave soldering is a manufacturing process in which electronic components are soldered to a printed circuit board (PCB) by passing them through one or more solder waves in a wave-soldering machine. The solder wave is created by heating the solder bath to its melting point, then passing the PCBs and components through it. Wave soldering is the most popular technique for manufacturing PCBs, accounting for more than 60% of all PCB assemblies.
  • Reflow Soldering: It is a process in which solder paste is applied to the surface of a printed circuit board (PCB) by a dispenser. Next, the PCB is placed in an oven where the solder paste is melted and made to flow over the surface of the board. Solder joints are then made by bringing the PCB and component leads in contact with each other. Reflow soldering is often used in mass production to solder surface mount components.
  • Selective Soldering: Selective soldering is the process of soldering specific components on a printed circuit board (PCB) while avoiding others. In selective soldering, only specific solder joints are melted, while the rest of the circuit remains unaffected. This allows for more efficient use of solder and can be helpful in preventing damage to delicate components.

What are the Steps involved in PCB Soldering Process?

There are a few basic steps involved in the PCB soldering process. They are:

  1. Prepare the work area by cleaning it and ensuring that all necessary tools and materials are within the reach.
  2. Place the PCB board on the work surface in such a way that it is easy to reach all of the solder points.
  3. Next, coat the solder points with a thin layer of solder, as this helps to ensure a strong connection.

Once this is achieved, follow the below steps:

  1. Preheat the PCB and the soldering iron
  2. Apply solder to the tip of the soldering iron
  3. Touch the solder to the joint to be soldered
  4. Apply pressure to the soldering iron while it is in contact with the solder and PCB
  5. Hold the soldering iron in place for a few seconds after the solder has melted to ensure a good connection
  6. Remove the iron and solder wire and inspect the solder junction for appropriate connection
  7. Clean the PCB

Must-have Materials/Equipment Needed for Soldering a PCB

There are a few key items you will need in order to solder a PCB. The first is a soldering iron. This is the tool that will heat up and melt the solder. Make sure to use one with a fine tip, as this will make it easier to work with small components.


The second item you will need is solder. There are a few types of solder available, but for PCBs you can use leaded or lead-free solder. Leaded solder contains lead, which makes it more durable and easier to work with than other types of solder. When choosing the solder, the most important factor is the type of metal being joined. Different types of solder are available for different applications.

Additional tools and materials that may be needed include:

  • Flux
  • Wire cutters
  • Screwdriver
  • Thin nose pliers
  • Wire cutters

Tips for Proper Soldering

When it comes to PCB soldering, there are a few key things to keep in mind in order to ensure a successful, high-quality solder joint. The following tips will help you produce quality solder joints every time:

  • Make sure your work area is clean and organized. This will help keep you from making mistakes.
  • Use the right soldering iron and solder for the job.
  • Use flux, as this will help to clean the surfaces to be soldered and also help the solder adhere to the surfaces better.
  • Use a quality solder because cheap solder can cause problems and may not create a good connection.
  • Use the right amount of solder, as too much solder can cause a bad connection, and too little solder can lead to a weak connection.
  • Make sure your soldering iron is properly calibrated and in good condition. A poorly calibrated iron can cause problems with your solder joints.
  • Preheat the PCB and components to be soldered.

Partnering with a PCB manufacturer who is an expert in all types of soldering can be extremely beneficial for your business. By partnering with a company that has a wealth of experience and expertise in this field, you can be assured that your products will be of the highest quality and that they will meet all safety and compliance standards. In addition, by working with a manufacturer like Suntronic – a reputed electronics contract manufacturer – who is well-versed in soldering, you can be confident that they will be able to quickly and efficiently produce your PCBs without any errors or delays.