PCB refers to an empty circuit board. In this state, the board does not contain any electronic components and looks like green slate with dividing lines and spaces. Therefore, the PCB itself cannot be used for work unless and until the entire assembly is complete.
On the other hand, PCBA is also known as the process of soldering and assembling electronic components on circuit boards and finished/assembled circuit boards. The finished PCBA is actually used for electronic devices rather than PCBs.
What is a circuit board assembly
Circuit board assembly is involved in various steps. It is a non-linear process, indicating that factors need to be considered, and the process can change and adjust according to these factors. The desired outcome and the use of PCBAs is one of the main considerations in determining components and the general circuit board assembly process.
The following are some of the parts and components that need to be carried out PCB assembly:
1. the basic printed circuit board or substrate
2. the electronic components that will be mounted on the board. This depends on the use of the board and the complexity of the device. For example, PCBAs for radios are relatively simpler than PCBAs for computers. In fact, some computers can have as many as 12 different circuit layers on the PCB.
3. Soldering materials such as soldering wires, solder pastes, and pre-made rods. Prefabricated rods depend on the type of soldering that will be performed.
4. flux
5. other soldering equipment such as soldering stations, wave soldering machines, inspection, test equipment and SMT equipment. The use of equipment depends on the expected results, cost and time resources. For example, the reflow soldering processes used in electronics are primarily vapor phase and infrared. Based on the above factors, one of these processes is selected.
When all the necessary components are ready, the assembly process can begin. But before we get into the assembly process (which is of a different type), let's learn more about the board itself.
The Three Main Types of Printed Circuit Boards
The circuit board is usually made of epoxy or other composite materials. It is used to physically support components and connect them electrically to form real-time circuits.
In the simplest sense, a PCB will consist of a thin layer of insulating material and a layer of copper foil, ****co-laminated to the substrate below (usually made of epoxy, fiberglass, or a similar composite material).
The number of layers on a PCB depends on the use and application. The lines or circuit traces on the PCB are created with the help of chemical etching. These lines help in the flow of current and connect various components together.
There are different types of circuit boards or PCBs.Depending on the type of application, the manufacturer will choose the PCB.Here are some of the most widely used types of PCBs:
Multilayer PCB
PCBs come in a variety of layers, including single-sided and double-sided. However, due to their limited applications, hobbyists use single-sided, while double-sided are often no longer used for mass manufacturing.
Multilayer PCBs are more common because they push the envelope after double-sided PCBs. There can be multiple layers of substrates in such PCBs. Insulating material acts as a separator between the dielectric and these boards.
Multilayer PCBs are designed to save more space than double-sided PCBs. Typically, multilayer boards come in 4,6,8,10 layer options but can be customized to have more layers. These PCBs can be used in computers, medical machines, smartphones and servers.
Rigid PCBs
PCBs not only have varying degrees of layers and sides, but they are also rigid. Typically, when talking about PCBs, we mean rigid PCBs. these types of boards use strong, non-flexible substrate materials such as fiberglass, epoxy, etc. The result is a board that is less prone to bending and more flexible for components. As a result, the board is less prone to bending and provides mechanical support for components and devices as a whole. The motherboard of a computer is a common example of a rigid PCB.
Flexible PCBs
Flexible PCBs are the direct opposite of rigid PCBs. As the name suggests, these boards are made from a flexible substrate material, such as plastic. The substrate material provides the board with enough flexibility to fit a variety of shapes and sizes. However, the flexibility is maintained in a way that does not damage the circuitry on the board.
Flexible PCBs are usually more expensive to design and manufacture than rigid PCBs. However, there are many advantages, such as replacing the need for heavy wiring in advanced equipment to increase space and reduce weight output. Like rigid PCBs, flexible PCBs may be single-sided, double-sided and multilayered.
Metalcore PCB
Metalcore
PCBs or otherwise known as MCPCBs are PCBs that are specialized for a defined purpose. e.g., the LED industry is growing rapidly but they are unable to efficiently solve the heat dissipation problem. By using MCPCB, this problem can be solved.
Metal core PCBs are made of metal plates, copper foils and thermal insulation. In a nutshell, PCBs have magnetic conductivity, excellent heat dissipation, high rigidity, and high handling capacity. In this case, the base materials are usually aluminum and copper. However, copper is known to outperform aluminum and is also more expensive.
Methods of mounting circuit board assemblies
The techniques used to assemble circuit boards and their various components are known as mounting technology board assemblies in circuits. Depending on the application, cost, size and other considerations, manufacturers use different kinds of mounting methods. Here are some of the most commonly used techniques:
Surface Mount Assemblies
Surface Mount Assemblies (or Surface Mount Technology, also known as SMT is a method of attaching electronic components that are upright on a PCB directly to the surface of a circuit board. The final circuit board is called a surface mount device (SMD). The technology was originally known as "planar mounting".
Most electronic boards produced today are manufactured using SMT. It has replaced the more traditional through-hole technology due to its increased circuit density and ability to produce results on smaller boards (more on this in the next point). Typically, SMT uses solder to attach components to the board, but in some cases, adhesive dots can also be used on the second side to keep the components in the reflow oven.
Board Through-Hole Assemblies
Through-hole technology (also known as "through-hole") is a mounting technique in which electronic components are inserted through holes built into a circuit board and then soldered to pads on the other hand. Soldering can be done manually or using an insertion mounting machine.
Through-hole technology replaces the traditional point-to-point construction. Through-hole became popular as double-sided and multilayer boards became more popular. It is used to connect components to conductive layers to ensure proper functioning of the board. These components are equipped with leads for connecting to the other side of the through-hole board.
In contrast to the SMT method, through-hole technology provides greater cohesion to the circuit board components as the units are placed through the board itself.
Electro-mechanical assemblies
Electro -
Mechanical assemblies use electrical and mechanical units to cover a wide range of functions, such as generating electricity, controlling switches and other mechanical tasks. Because electromechanical assemblies are typically used in applications with complex wiring and components, the components need to be manually placed together.
As a result, it can often be time -
consuming. However, major manufacturers like RayPCB like us to use this technology and break the process down into segments and use experts in each segment. As a result, we can shorten the lead time.
Common Uses for Each Type of PCB Assembly
Surface mount technology is most commonly used in personal computers and is still in use. It is one of the most widely used technologies in the electronics field and is used in a wide range of consumer electronics including smartphones, computers, televisions, microwave ovens and more. But before the introduction of SMT, it was a through-hole technology that dominated the personal computer market.
In fact, IBM pioneered the process and brought it into the mainstream. Today, through-hole technology is used more for bulkier components, such as electrolytic capacitors and semiconductors, because it can hold components better than SMT.
Electro-mechanical assemblies are commonly used for AC and DC power distribution, computer interfaces and control systems due to their versatility in power-enhancing mechanical functions.
Conclusion
PCB is a very near and dear part of our contemporary life, though we still don't notice it. Over the decades, the technology for efficiently assembling and mounting components has rapidly evolved into quick-to-point structures from through-hole to SMT. Moreover, each has its own pros and cons that make them well suited for certain tasks and not others