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The Differences Between PCB and PCBA in Design, Process and Costs

PCB and PCBA

If you are new to the world of electronic devices and their components, you must have come across two seemingly similar terms, PCB and PCBA. To understand the similarities and differences between the two, it is important to understand their meanings first. This will further help you understand whether you need to hire a PCB manufacturer or a PCBA company.

Find in this blog the meanings of PCB and PCBA, the types of PCBs, the difference between PCB and PCBA in terms of design, process and pricing, and how to decide which service provider to hire for your requirements.

What is a PCB?

To understand the difference between PCB and PCBA, you must first understand what a PCB is, its working principle, applications and types.

PCB or printed circuit boards form a very important part of most electronic devices as they hold almost all the interconnections necessary for the device to work well. Commonly, green in colour, a board with copper pathways that you must have seen while getting some electronic device repaired is the board infamously known as a PCB. Made of non-conductive material such as composite epoxy or fibreglass, PCBs also provide mechanical support to delicate components.

What is the working principle of a PCB?

Any electronic device needs complex circuits and interconnections among its various components like diodes, resistors, transistors, etc. Connecting them directly without any medium may cause issues like tangling of wires, short circuits and complications in the assembly process.

Therefore, to remove this complexity, PCB boards were designed. These are non-conductive boards with conductive pathways that carry electrical connections among various components. The pathways may be present on the outer surface of the board or embedded internally. So, the components can be easily assembled at their assigned points and the interconnections develop automatically with the help of pre-inscribed conductive pathways present in the PCB.

pcb bare board

What are the applications of PCB?

PCBs are present in almost all the devices you use on a daily basis. This includes:

  • Mobile phones
  • Laptops
  • Computers
  • TVs
  • Digital watches
  • Calculators

You must be surprised to know that in addition to the above-mentioned devices, PCBs are also used in a number of complex devices with critical applications. Some examples are:

  • Automotive industry-based equipment
  • Industrial machinery
  • Medical devices
  • Specialised military weapon systems

Continue reading to understand what is the difference between PCB and PCBA.

What are the different types of PCB?

PCBs can be classified on the basis of the number of layers they have. So, they can be single-layered, double-layered or multi-layered.

  1. Single-layered PCBs are the simplest of all types of PCBs, made of single layers of substrate, conductive material and solder mask each.
  2. As the name suggests, double-layered PCBs have two layers of conducting material. These are present on the two sides of the board. Usually, double-layered PCBs are smaller in size than single-layered PCBs.
  3. As you must have guessed by now, multi-layered PCBs are made of more than two layers of conductive material. Due to their complex structure, their manufacturing process and applications are also complex.

PCBs can also come in types like flexible, rigid and flexi-rigid.

What is a PCBA?

PCBA, or PCB Assembly, is basically a PCB board but with all the components mounted and soldered to it in a way that they are functional as per the requirement. There are three main ways to prepare a PCBA. These are SMT (surface mount technology), PTH (through-hole technology) and manual assembly. Now it will be a piece of cake for you to understand “what is difference between PCB and PCBA”.

What are the different methods used to fabricate a PCBA?

SMT, PTH and manual assembly are the methods used for PCB Assembly. A PCBA can be fabricated using one of these three processes or a combination of two or more of them. Each process has its own benefits and disadvantages. Which process is chosen depends upon the PCB type and requirements.

1. Surface Mount Technology or SMT

True to its name, in this technology, the components are mounted directly on the PCB surface. Components on both sides of the PCB can be assembled via SMT. This assembly process is carried out using solder paste. SMT is one of the most used PCBA technologies because of its high automation and flexibility.

2. Through-Hole Technology or PTH

In this process, first, holes are drilled in the PCB board and then, the leads of the components are inserted in these holes. This ensures stronger bonds making it more durable but the process is more time-consuming than SMT. PTH is widely used for prototyping purposes as the connections made via this technology are interchangeable.

3. Manual Assembly

Sometimes, electronic components are required to be assembled manually as they are too delicate or complicated to be assembled via a machine. In such cases, a manual assembly process is used. This is often used to assemble prototypes as it is cheaper and takes less time than PTH or SMT. However, if a large number of PCBA are to be fabricated by the manual process, the unit costs can go too high. Also, this process may not generate the desired results as its quality, efficiency and precision depend upon the worker’s skills.

Due to the different benefits and drawbacks of these technologies, many times a combination of two or more processes is used for PCB Assembly. This helps maximize the benefits and minimize the drawbacks.

pcba with components

What is the difference between PCB and PCBA?

Now that you have learnt about PCB and PCBA in detail, it will be a no-brainer to understand what is the difference between PCB and PCBA.

PCB and PCBA are different from each other but are quite interrelated. While PCB is a bare board made to be assembled ultimately, PCBA is an assembled PCB board with all the components and connections. PCB is a non-functional board that cannot be used without assembling and PCBA is the final assembly that cannot be produced without a PCB bare board.

So, if PCB and PCBA are so dependent on each other and both are equally necessary for a well-functioning electronic device, then why do you need to decide which process to outsource?

This is because both PCB manufacturing and PCB assembly come with their own benefits and shortcomings. One must recognise their requirements clearly and then hire a company accordingly to make the most out of their money. 

To deduce whether you need to hire a PCB manufacturer or a PCB Assembly company, you must first understand the difference between PCB and PCBA in terms of design, process and cost.

What is the difference between PCB and PCBA in terms of design?

The designing of both PCB and PCBA is quite a crucial step in the fabrication of the two. A minor error or negligence may lead to the failure of the entire device. Therefore, it is necessary to work with experienced professionals while working on the design of PCB and PCBA.

PCB and PCBA differences are not limited to their definition only. Their design processes also differ from each other. Usually, software like CAD is used to design a PCB layout. Layer stack up, trace routing and signal integrity are focussed upon during the designing of PCB. On the other hand, the designing process of PCB Assembly involves schematic capture for connectivity.

What is the difference between PCB and PCBA in terms of manufacturing process?

A long process involving steps like printing, substrate formation, etching, lamination, plating, solder mask application, silkscreening and surface finish is carried out to manufacture PCBs. Multiple rounds of testing and inspections are also carried out at several stages of the manufacturing process. These testing and inspection are done by automated machines and/or manually by the designated staff. The PCB manufacturing process gets more complex with an increase in the number of layers in the PCB.

PCB Assembly involves the SMT, PTH and/or manual processes as detailed above. The functioning of the final product depends critically upon the quality, precision and efficiency of the assembled PCB.

What is the difference between PCB and PCBA in terms of costs?

One of the most important aspects of PCB and PCBA differences is the difference in their pricing.

The cost and pricing of a PCB depends upon its type. More the layers in a PCB, the costlier its manufacturing will be. Similarly, the cost of PCBA depends upon the type of technology used and the components required for the device.

However, even the multi-layered PCBs are generally less expensive than a fully-equipped PCBA. This is because PCB is a bare unassembled board and thus, has a lower market value as compared to PCBA. On the other hand, PCBA requires a well-designed PCB board, expensive components and skilled staff for efficient assembly.

How to decide which service provider to hire for your requirements?

Some hire a PCB manufacturer while others a PCB Assembly company. When both PCB and PCBA are required ultimately, then how do people decide which service provider to hire, you must wonder!

PCB manufacturing companies are usually hired when someone has an expert team or resources to assemble the PCB in their own facility. This also helps them save costs and turnaround time.

However, those who do not have an in-house PCB Assembly team, hire a company that offers them both PCB manufacturing and assembly services. Outsourcing this task to an experienced and certified company, like Viasion Technology Co. Ltd., generates massive returns on investment in the long run.

Additionally, some may also get the PCB bare board manufactured at their personal facility and then outsource the task of assembling.

Consider your requirements, budget and expected turnaround time, and hire a company accordingly. In any case, avoid hiring two different companies for PCB manufacturing and assembly requirements as this may double up the packaging and shipping requirements, further increasing the cost.

The Bottom Line

While PCB and PCBA seem similar and are, in fact, quite interrelated, they are a world apart. One must understand the difference between PCB and PCBA well before hiring any company to make the most out of their money. For the best assistance and one-stop PCB-related services, connect with Viasion Technology Co. Ltd., one of the most trusted companies in China. Check their website for more information.

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