Guideline

The Beginner’s Guide to Soldering PCB Boards: Essential Tools and Techniques

Soldering PCB Boards

PCBs are the backbone of the majority of electronic devices that we constantly use in our everyday lives. Usually, a copper-clad laminate called r FR-4 is used to create these PCBs. The actual building of the circuit is finished by aligning and connecting the PCB components onto the board. The creation of bare boards, assembly, and packaging are only a few of the processes in the PCB manufacturing process but soldering is arguably the most sensitive step in the whole process.

During PCB fabrication, many components necessary for the board are attached together using a variety of soldering techniques, but the equipment utilized is the same for all techniques. If you’re interested in learning how to solder PCB board, you should be well-versed on the necessary instruments, methods, and other aspects of the process to achieve success. You can discover all the information you’ll ever need to comprehend the PCB soldering procedure in this article.

What is PCB Soldering?

Soldering is the method of joining components of a printed circuit board together with a metal that has a low melting point in comparison to other metals. It is the primary method of securing electrical components to a printed circuit board (PCB) board, which is necessary for the PCB board to perform as intended. There are several types of solder materials, however, for convenience, they are often combined to have low melting points. The most popular combination is an alloy of lead or tin combined with brass or silver, and then the metal is melted by the soldering iron, enabling it to be utilized as glue to join parts.

People interested in understanding how to solder PCB should know that the parts merge together as a single unit only when the solder material cools and solidifies, and never before that. An acidic substance known as flux is also used during the process to stop unwanted oxidation. Though they’re usually less effective, several lead-free variants, such as copper, brass, or silver, are now available for soldering in an effort to reduce lead consumption owing to safety and environmental concerns.

Essential Tools for PCB Soldering

Befor talking about how to solder PCB, we need to prepare the essential tools first. Without appropriate equipment and supplies, it is simply impossible to perform the soldering process on a PCB. Here is a list of tools that are necessary for the soldering process:

1. Soldering Iron

The soldering iron, sometimes referred to as a soldering gun, is the most crucial piece of soldering equipment, and the two main parts of a soldering iron are the handle and the tip. Electric heaters and soldering irons use the same type of heating element because when electricity passes through an element, heat is created. The iron component of the soldering iron is heated as a result, and the heat is subsequently transferred to the solder tip.

  • Rest: Although the rest is not an integral component of the soldering iron, the rest is a basic feature that allows you to set the iron aside when you need to free up your hands. If you should place the heated iron directly on this surface, this rest is the component that prevents your counter or workplace from being damaged.
  • Solder wick: Solder wick can be described as a type of eraser because copper wire is used to make the wick, which meshes together to expel extra solder that isn’t needed for the soldering process.
  • Wand: This is a part of the soldering iron that you will grasp, and typically, the wand has a padded grip that shields you from the iron’s heat while providing you with something to hold comfortably.
  • Tip: This is the iron component that will come into touch with the PCB board electrical components as this is the heated-up portion of the device that you use to manage the soldering process.

Soldering PCB Boards by Iron

2. Solder Wire

In the production of electronics, the most used type of solder wire is an alloy made of forty percent lead and sixty percent tin, and when it cools, it has a melting temperature of 190 degrees Celsius. This alloy is available in wire form in many sizes, but it is preferable to utilize thinner gauges rather than thicker gauges. For regular applications, solder wire in the gauges of 18 is a good option, and so is 22.

3. Solder Flux

In the soldering process, flux is crucial because it is used to chemically clean the metal surface joint both before and after soldering, reducing oxidation. The flux facilitates the “wetting” and soldering processes and dissolves the oxide from the metal joint surface, preventing the production of solder balls. The adhesive force known as “wetting” between the solid copper wire and liquid solder is what pushes the molten solder drop to spread out across the surface and create a strong electrical junction. Conversely, cohesive force prevents contact with the metal or copper surface and leads to the creation of solder balls.

  • Organic acid flux: When soldering metal contacts, an acid-based flux makes sure that oxides are aggressively removed. Because this flux dissolves in water, remnants must be cleaned up after soldering in order to stop corrosion.
  • Alcohol-based no-clean flux: Solder paste may include alcohol-based no-clean flux, or they may be combined with rosin if necessary. They also don’t spray as much as other flux materials and evaporate rapidly when heated.
  • Rosin flux: Made from conifers, rosin is a solid type of resin, and rosin flux residue won’t lead to corrosion, which is why it’s utilized in situations where removing residue through organic acid flux can be more challenging.

4. Solder Sucker

Solder sucker is used in the process because it removes extra solder and facilitates section removal from the PCB when needed. However, you should remember to use caution while using a solder sucker since certain cheap PCB hole pads are fragile and might shatter under the sucker’s powerful suction, making the board hole useless.

5. Soldering Clamp Stand

Soldered wires are typically quite tough to work with but to hold the wire, there are clamp stands with crocodile clips that are available in the market. To make soldering easier, they also incorporate a PCB holding vise that comes in very handy during the soldering process.

6. Solder Paste

The color of the solder paste is gray and resembles putty, and this paste is used to attach different components that need to be mounted on the PCB board.

7. Soldering Station

The soldering iron’s heating is controlled by an inbuilt regulator that controls the amount of electrical energy flowing through the element that generates heat. This process is unique and several soldering station manufacturers provide these components with control equipment, a switch, and a display for temperature on the front panel.

Soldering PCB Boards by SMT

PCB Soldering Techniques

If your interest is piqued by how to solder a PCB circuit board, you must know that the nature of soldering has historically been a major cause of hardware failure. However, by ensuring that the soldering is of the highest caliber, the PCB assembly process can be enhanced, and the overall gear can meet the highest standards. There are multiple methods to solder a PCB, but all of them can be categorized under six basic categories that we will explained below.

1. Soft Soldering

The most common soldering method, soft soldering, is used to join tiny parts to the PCB layout and these elements, which normally have a mild melting temperature, will begin to melt at the extremely high temperatures of the energy source. To connect the components to the board, though, a further procedure needs to be followed rather than just melting the component, and this additional step in this instance requires using a filler metal, usually a tin-lead alloy. The most important requirement for this metal is that the temperature at which it melts must be greater than 750 degrees Fahrenheit. This alloy is crucial to the soldering process because it acts as a binding substance, maintaining a strong bond between the piece of equipment and the printed circuit board. A gas flame is typically used to provide sufficient temperature needed for this task, which melts the alloy and fuses the part to the PCB permanently.

2. Hard Soldering

By distributing a solid solder across the holes of the components that become free when they are exposed to high temperatures, hard soldering strengthens the link between two distinct metal elements. Silver soldering and brazing are the two minor subprocesses that comprise the larger process of hard soldering. This technique is applied to circuit board upkeep and the fabrication of tiny components because silver is free-flowing, yet by itself it’s not always the best material for filling a hole. For this reason, distinct fluxes are often utilized to produce dependable silver soldering that will last.

3. Braze Soldering

Braze soldering surpasses both soft and hard soldering in terms of quality and forms stronger connections between printed circuit boards and electrical parts like capacitors, inductors, and transistors. To adhere electrical components to circuit boards, it employs high temperatures. While brazing and hard soldering are comparable processes, brazing entails melting the metal components’ undersides in order to set them to the board. It is among the best soldering methods for large-scale PCB manufacturing and produces the least amount of heat distortion.

Reflow Soldering

4. Reflow Soldering

Reflow soldering is a type of SMT soldering process, and SMT makes PCB assembly of electronic gear far more productive. It is also the most widely used mechanical technique for joining surface-mount components to PCBs.

When SMT is used for the PCB soldering, it results in much faster completion times and stronger final products. The soldering processes required by PCB manufacturers for reflow soldering must ensure that the parts are retained in place during the soldering process and that they are not damaged. By preheating the components and then melting the solder without scorching them, the procedure seeks to establish solder junctions.

A type of solder paste is created by mixing fluxes and granular solder together in reflow soldering and the electric parts are temporarily connected to their respective terminals using this paste before being soldered. After the solder has completely melted away, the connection is rejoined by reheating the entire structure in a reflow soldering furnace or through an infrared source of light. Preparing for this process is the initial step, which allows construction boards to reach the required temperature while adhering to heat profile.

Additionally, it eliminates the flammable compounds in the soldering paste, facilitating correct melting of the alloy. The failure of the fluxes in the solder paste that is used to heat up at the appropriate temperature will lead to weakened metal coupling. Throughout the technique, the soldering alloy changes into melted metal when the maximum temperature is employed during this process. Heat management is a key component of the reflow soldering process but you need to always remember that overheating can cause damage to circuits or devices used in surface mount technology.

After cooling, solder paste hardens, and connection padding is used to connect the elements to the PCB. Reflow soldering is primarily utilized in smaller-scale industrial applications when rapid, inexpensive, large-scale manufacturing is not necessary. For production processes that employ reflow soldering techniques, exterior mounted electronics are connected to PCBs using machinery, also known as component positioning equipment.

Mistakes might happen during the procedure, so a plan for adjustments needs to be in effect and professionals usually take the manual approach to repair broken surface-mount elements, such as malfunctioning PCBs.

5. Wave Soldering

This is a type of mechanical soldering process that can quicken the production of the PCBs in large amounts. Solder “waves” produced by the machine attach the components to the board, and when the PCB cools, the process securely holds the components in place. The first step is flux spraying when soldering performance is ensured by cleaning metal surfaces. Flux helps solder more smoothly before the preheating stage starts.

During the heating session, the circuit board will be heated by making it pass through a temperature tunnel and the solder paste will transform into a liquid as the temperature progressively rises. This process creates waves from the edge boards above and on the PCB board, and components get firmly attached. The soldering will be successfully completed once the board has cooled to room temperature. If a manufacturer needs to fulfil the rising demand for electronic products, wave soldering is the recommended method for increasing PCB assembly speed and efficiency.

6. Through-Hole Soldering

The through-hole soldering process became antiquated with the introduction of SMT components, but the through-hole process still has its use. SMT sectors are doing well due to consumer need for more affordable and compact hardware, but smaller companies continue to provide services in their own unique ways, including employing through-hole soldering techniques. When compared to SMT components, through-hole components will often be stronger and more practical. As a result, through-hole components might still be preferred in contemporary aviation applications that need consistent quality under extreme circumstances.

Conclusion

PCB fabrication and assembly involve many tools and techniques. Take soldering for example, the soldering process requires different tools and techniques based on personalized requirements and specifications. And this blog post gives a full description of how to solder a PCB circuit board for beginners. If you are looking for more detailed information about how to solder PCB, drop us a message right here, and we’ll get back to you as soon as possible!

    Request for Quote