What is a PCB?
A PCB (Printed Circuit Board)is a critical module that is used to connect electrical components. The board makes use of pads, conductive traces, and other copper-etched features to facilitate the functions of electrical devices effectively.
Experts of PCB design create the boards by printing/depositing a thin layer of conducting material on an insulating board – known as the substrate. Electronic components are then individually placed on the substrate and soldered to the appropriate interconnecting circuits. The substrate has ‘contact fingers’ along the edges that are used for connecting to external devices or even other PCBs.
Majority of the electrical devices we use these days run off PCBs. From basic devices like radios, and pagers to sophisticated instruments like radar equipment and computers. The PCB circuits can be configured to perform single or multiple functions, as desired.
1.1 Types of PCB
Now that you know what a PCB is, you should know that we have more than one kind of PCB. There are mainly three types of PCB, and they are:
A single-sided PCB has all its components installed on only one side of the board. Proper construction ensures that all components are well sited and secured.
A double-sided PCB is used when the components to be placed are too much for a single side. Electrical connections between both sides are enabled by drilling holes straight through the substrate in strategic positions. Internal pores coated with a conductive material, to achieve efficient current.
Consecutively printing layers of circuitry design a multi-layered board on each other; separated by layers of insulating material. Components on the surface are connected to the appropriate circuits by drilling plated-holes to the desired layer.
PCBs are crucial to every aspect of our daily life. The appliances and resources we utilize to keep our lives running are based on printed circuit boards. Read on to learn how this amazing technology design is the design.
The design of a PCB offers limitless possibilities. Each board is designed to carry out a specific function for a unique product. For PCB design, experts employ the use of CAD (computer aided design) systems and dedicated software to lay out the circuit pattern of the board. A board designer must be able to maximize the allotted space for the board and achieve the desired functions.
After the circuitry has been laid out, a negative image of the design (mask) is printed onto a transparent plastic sheet with precise dimensions. The mask colors areas not part of the design in black; and the circuitry appears as clear against the background. The locations for contact-point holes are also easily distinguishable from the overall design.
1.3 Common Materials Used
You already know the key processes involved in PCB design. It is nothing short of amazing how a small piece of tech can have such a powerful impact. The importance of PCBs means that only the best and most durable material is used in its creation. Read on to find out what items make up the PCB.
In PCB manufacturing and printing, the substrate material used is usually a glass fiber reinforced epoxy resin. High-end board production involves pairing the glass fiber reinforced epoxy with a copper foil that is bonded to one or both sides of the substrate.
Boards produced from using paper reinforced phenolic resin with a copper foil bonded to it; tend to be less expensive. These PCBs can be readily found in household electrical devices and appliances.
The printed circuits of the board are made out of copper. The material is etched or plated onto the surface of the substrate in the desired pattern. To prevent oxidation of the copper circuits, they are coated with a layer of tin-lead which provide the required protection.
The contact fingers on the outer edges of the substrate are first plated with a tin-lead mixture, followed by nickel, then finally gold for maximum conductivity.
I believe we have covered just about all there is to know about PCBs. However, that’s just one side of the coin. In the next chapter, we will delve into what is PCBA and why it’s so important.
What is a PCBA?
PCBA stands for Printed Circuit Board Assembly. It refers to the board obtained after all printing and mounting operations have been completed. When choosing PCB vs. PCBA, the critical point of note is that a PCB is just a board with circuitry printed on it. PCBA is the complete package; it has been fitted with all necessary components and is ready for deployment for its desired purpose.
The components that can be mounted in PCB Assembly include capacitors, inductors, resistors, diodes, triodes, modules and more. A PCBA will undergo a process known as reflow furnace heating; to help establish a mechanical connection between the board and it is accompanying components.
PCB Assembly Is a delicate process and should be taken very seriously. It can only be carried out by a skilled technician and specialized computer systems. The next chapter talks about the assembly methods used in PCBA manufacturing.
There are two primary methods for assembling components in a PCBA. These are:
·Surface-Mount Technology (SMT)
This method of PCBA is highly suited for small-sized circuits and components. It is a fully automated PCB Assembly process that features three main steps. First, the printed circuit board gets a generous application of quality solder paste from the printer. Next, install all the necessary components in their respective locations. Finally, the board is passed through a 500-degree furnace that liquefies the solder past thereby sealing all components in place.
·Thru-Hole Device (THD)
THD technology is merged of both manual and automated operations. It also involves three steps of execution. The first step entails the components being manually placed on the board by a technician. The second step deals with the inspection and rectification of all set components. In the third step, the whole PCB Assembly undergoes wave soldering. Wave soldering is the process of passing an assembled board through a wave of liquid solder at 500-degrees Fahrenheit.
PCB vs PCBA
So far, we have learned what a PCB is and also, how PCBA works. With this important knowledge in the bag, it’s time to find out the differences and what sets them apart.
When discussing the critical topic of PCB vs PCBA, one needs to take due note of the most distinguishing factor. A PCB is only a blank circuitry board, while a PCBA is a fully functional board with the required components attached.
A PCBA may be viewed as a completed board which can only be made after the PCB has been fully developed.
It is essential to be able to spot the differences between a PCB vs PCBA. The major differences are:
A PCB (printed circuit board) is a lot easier to produce; since it requires no assembly. While a PCBA is more complicated due to the various components that need to be attached and the subsequent furnace soldering of its connections.
For the same board, the cost of manufacturing a PCB is far lower to the cost incurred in producing a unit of PCBA. The additional components that are attached to the PCBA carry substantial costs that ramp up the overall cost of the completed PCBA.
A PCB is a ‘blank board.’ It has no components that facilitate the passage of electricity through it. PCBA, on the other hand, has all the essential components attached and is ready for deployment.
PCBs are packed with vacuum-packaging while PCBA boards are packed using compartmental or anti-static packaging.
The applications of PCBs extend across all electrical devices that we use. From simple pagers and alarms to complex types of machinery like MRIs and radar equipment. The modern society as we know it runs on the back of PCBA. Our cars, media devices, and home appliances would all be imaginary luxuries; if we didn’t have printed circuit boards (PCB)and printed circuit board assembly (PCBA).
As complexity increases, the boards are being optimized to be smaller and more powerful. We are even in the process of developing 3D circuits that offer extraordinary capabilities for such a futuristic design.
It is no doubt that PCBs are the essential building blocks of all electrical systems. Our society relies on the continuous performance of circuit boards for the effective running of our affairs. If this fundamental piece of technology were to fail, all human systems that run on electricity would be rendered unusable.
The future holds some exciting prospects for the development of PCBs and PCBA in general. We are steadily edging towards more optimized designs, and the ability to pack super complex functionalities into tiny sized circuit boards.