The use of PCBs is rather widespread in the world.
Found in almost every single aspect of our lives, they have become an almost indispensable part of daily living.
From toys to spacecrafts, and everything in between, they can be found everywhere in the world, with their use only increasing with the passage of time.
There is a lot that goes into the manufacture of PCBs, from the early stages to the final steps.
Of the many steps that exist, one of the more important is that of soldering. Named after the material used for the process, solder, an alloy of tin and lead, it is used for the bonding of two or more components in not just PCBs, but just about every other electrical application that exists.
An important part of getting the finished product out into the market, they play a key role in the industry, every step along the way.
When it comes to the soldering of PCBs, the steps are basically the same, albeit with some minor changes and modification.
Given in the points below, are the some of the most important steps that go into soldering printed circuit boards.
1.) Some Basics
Although the soldering process in PCBs is rather different, there are some basics which remain the same everywhere.
For one thing, the process in which the soldering takes place is rather standard, in the sense that the soldering material is melted with the help of a hot iron, with the melt alloy solidifying at the interface between two or more components to seal them together.
Although the exact nature of the solders used for PCBs may vary, this process is more or less the same, and is widespread across the industry, for the purpose of attaching components to the PCB board.
2.) Basic Preparations
There are a few basic preparations to be done before the soldering takes place.
General Preparations: For one thing, the amount of solder, the components to be attached, a solder iron and any other requirements need to be ready. The solder wire is to be present in sufficient quantities, while the iron needs to be hot before the application takes place.
Preparation the Soldering Tip: Ensure that the tip of the soldering iron, also called a soldering tip, is coated in solder. It is important, as the alloy may otherwise collect what is known as ?flux residue?, and not allow for the adequate conduction of heat. To ensure that this doesn?t take place, it is important to have the entire tip?s surface covered in solder. This may require a considerable amount of solder. Once the solder tip is covered in solder, it is important to wipe off the flux residue from the surface, with the help of a wet sponge. The process is a very important step, and is also referred to as the ?tinning? of the soldering tip.
Preparation of the Board: In addition to preparing the soldering tip, it is also important to prepare the board as well. There are a few things to be taken into account, depending on the nature of the board.
For one thing, the board needs to be cleared of dust, in order to allow for the solder to bond the components to the board. This may be achieved with a simple brush in minor cases, to solvents such as acetone in others. Using blasts of compressed air can also be helpful in clearing away any dust.
Should the board be covered with deposits of any kind, a fine grade steel wool can be put to use. Do note that many boards have a very thin layer of circuitry and other layers, meaning that excessive pressure or force can damage the design.
The goal here is to ensure that the surface is clear the surface of any dust, substances or other particles, which may hinder with the overall soldering process.
3.) The Placing of the Components
Before the components can be placed, a few steps need to be taken, in order to ensure that everything works as per the original plans.
Regardless of the number of components, it is generally a good idea to start with the smallest, flattest or the easiest elements first, and everything else later on. In addition to this, it is also a good idea to place the components of one side first, and then move over to the other, unless the schematics require it otherwise.
Some of the easiest components to place include, among others ICs and signal diodes. Once these components are placed, other components can be added, which include non-socketed ICs, etc.
To have the components placed, one will have to have the place the leads as required through the holes drilled into the board. The leads at the board?s bottom will need to be bent at a 45 degree angle, especially in the case of leads such as those of resistors. Likewise, shorter leads such as those found in IC sockets can be held in their place, using masking tape or slightly bent and clamped onto the board.
4.) The Soldering Process
After the components are placed, the soldering can be applied.
To apply the solder, one will have to place the soldering tip at the location where the bonding is to take place, and then touch the tip of the solder to the solder pad and lead, but ensuring that one doesn't touch the tip of the iron.
If the temperature is right, the melt solder should flow around the lead and pad, after which the flux melt will liquefy as well, bubbling around the joint, along with smoke being released from the joint as the solder melts. Add the solder until the entire pad is coated, while the solder creates a small 'mound'. Ensure that too much solder isn't used in the process, and wait for it to cool down and solidify. Also make sure to not shake the joint while the solder is wet, so as to ensure that you don't end up with what is called a 'cold joint', where a joint is known for its grainy appearance and dullness.
Also, make sure that the joint is inspected after it is completed, and make any adjustments that may be required. The adjustments here include, among others, cold joints, trimming excess lead if present, cleaning up excess flux residues using a substance such as methyl hydrate and blowing the surface dry using compressed air.
In addition to this, it should be added that increasingly, the process is entirely automated in factories, especially when the production quantity happens to be that of bulk orders.
Regardless, the key features, steps and procedures will remain the same here, albeit done by machines rather than human technicians.
To sum up, the above mentioned steps are some of the key details that go into the soldering of printed circuit boards.
Do note that there are indeed other details as well that go into this, which varies from case to case, depending on the needs of the final product.