December 25, 2023

Difference Between PCBA and PCB

Do you think that PCB and PCBA are the same representations of the technology and electronics industry? We agree that most people use these terms for the same purpose.

But let us know the truth. PCB Assembly and PCBA assembly are two different terms in electronics with their own unique features, working, advantages, and applications.

PCBs aren’t functional on their own, but they’re the essential framework needed to build circuits on. PCBAs, however, are fully functional, complete with all the circuitry and components that support most modern technology and systems both connectivity-wise, and physically. 

We’re going to learn how to define PCBs and PCBAs and how to distinguish between the two. 

PCB-vs-PCBA-comparison

What is the Definition of a Print Circuit Board?

A PCB is the basic building blocks of all modern technology and devices. They provide mechanical support and connectivity to different electronic components within a system. 

A PCB itself is constructed with composite epoxy or fiberglass, with conductive pathways embedded into the structure. These conductive pathways are built onto a PCB keeping in mind the technology they are made for, making each PCB different. 

For more on PCB materials, check out Most Common Types of PCB Materials.

Close-up-of-a-green-PCB-with-labeled-circuits

What is a PCBA?

After a PCB has been constructed, it’s time to assemble the full circuit by using active and passive electronic components. These include resistors, transistors, diodes, SMC capacitors, etc.

They’re attached to the PCB with different methods according to the specifications of each component, and can be SMD or SMT components. 

Assembling a PCBA can be done either by soldering electronic components mechanically or through automatic soldering techniques like wave soldering for through-hole components. Other common soldering methods include reflow soldering and mixed soldering technology. 

A PCBA is formed when all these components are soldered on top of a printed circuit board or PCB. Once done, the PCBA is ready to be used in devices. 

For more details on the assembly process, visit Basic Things You Should Know About PCB Assembly Process.

What are the different types of circuit boards used in electronics?

PCBs come in many forms, like

  • Single or Double Layer
  • Multi-layer

As the names imply, Single Layer PCBs are the simplest. They have just one layer of conductive material and just one layer of solder mask. Once made, the solder component will be marked with a silkscreen. 

You might think double layer PCBs are bigger than single layer ones, but you would be wrong. Double layer PCBs obviously have more conducting material on them, and it makes them more flexible. 

Then comes the most advanced form of PCBs – the multi-layer PCB is capable of supporting some of the most complex hardware capabilities that exist today. There can be different types of circuit boards such as flex-rigid, rigid or flex PCBs.

Close-up-of-a-detailed-circuit-board-with-components

What Are the Most Common Assembly Methods for PCBs?

PCBs are assembled in a number of ways, with factors like the number of components being put on a PCB and their intended function and capabilities playing major roles in determining what the assembly method would be.

For certain components, the surface mount method is best, but in other cases, you might want to employ the through-hole method instead. 

The Surface Mount assembly method is an industry-standard. As the name implies, components for the circuit board are mounted and soldered on the surface. 

This assembly method is used most commonly while using multi-layer PCBs, and makes it possible for the end PCBA to be compact yet powerful. 

The solder is first poured onto the multi-layer PCB, with components going on top. Once everything is at its right place, the solder is heated up to a melting point, allowing components to adhere securely to the printed circuit board. 

For bigger and cheaper assembly, some components for a PCBA are attached and soldered into the PCB itself through holes drilled into the PCB. Components attached to PCBs through this method come with leads that can be put through these holes before they’re soldered in. 

In addition to keeping all components in place, the solder ensures connectivity of each component to the main circuit. 

  • Mixed Technology

Not all the components on a single PCB are attached through the same method. According to the needs and specifications of each component, they might be attached through-hole or by mounting them on the PCB through SMT. PCBs assembled through this method are said to be assembled using mixed technology. 

Additionally, SMT and through-hole attachment aren’t the only methods used. In some cases, no soldering is necessary in the assembly process, making it possible for manufacturers to construct smaller, more powerful PCBAs. 

Learn more about the assembly processes and techniques in our comprehensive guide on PCB Assembly.

Multiple green PCBs with white markings

Different Types of Materials Utilized for PCBs in Electronics Industry

The most commonly used materials to construct a PCB are composite epoxies, fiberglass, or laminates. While these are the most common types, various other forms and materials exist due to constant innovation and development in this field. 

The conducting materials used in PCB construction are usually copper. To protect both the conductive material and supporting circuit board, PCBs are often coated with tin-lead, especially to keep the copper from oxidizing.

For an added layer of protection, the corners of each PCB are often protected with extra layers of tin-lead, or even nickel or gold for increased connectivity. 

For more on PCB materials, check out Most Common Types Of PCB Materials.

What is the Cost of PCBAs?

Printed circuit boards aren’t simple to manufacture. As the backbones for all advanced technology commonly used today, they require extreme levels of precision and quality in each unit.

Factors such as labor costs, tooling, and setup charges, the turnaround time for production, and the quality of the technology being produced all play crucial roles in how much PCBs cost to produce. 

Don’t forget about shipping and packaging costs if you’re thinking about manufacturing PCBAs offshore.  

Labor costs vary widely depending on the geographical location of your manufacturing facility and can be influenced by the time of year, local and national regulations, and even automated factory labor when you want to automate this production process. 

Manufacturing costs can be cut drastically by producing standard PCB designs instead of creating specialized boards that would require custom setups or more manual labor. 

Your chosen method of assembling the PCBs will also factor into how much the final product costs to produce – SMT can be automated to a great degree, which makes production faster and cheaper.

However, the initial costs for the equipment could be quite high. Through-hole assembly, however, will cost you more in manual labor than assembly through SMT will. 

Expedited shipping, long working hours for your workers, and using high-quality materials will add to your final production costs as well.  

PCB-vs-PCBA-comparison-with-close-up-images.

Differences between PCBs and PCBAs

Understanding the distinctions between Printed Circuit Boards (PCBs) and Printed Circuit Board Assemblies (PCBAs) is crucial in the electronics manufacturing industry. Here are the key differences:

Definition and State:

  • PCB: A PCB is a bare board made of insulating material with conductive pathways etched or printed onto it. It serves as the foundation for creating an electronic device but does not perform any electronic functions independently.
  • PCBA: A PCBA is a PCB that has been fully assembled with all its necessary electronic components, such as resistors, capacitors, and integrated circuits. It is ready to perform its intended electronic functions.

Learn more about a Resistor on PCBs, check out How to Read a Resistor on PCBs.

Components:

  • PCB: Contains no electronic components. It includes the substrate, copper, solder mask, and silkscreen layers.
  • PCBA: Includes the PCB and all the electronic components required for the circuit to function.

Fabrication Process:

  • PCB: The fabrication process involves designing the board layout, transferring the design onto the substrate, etching away excess copper, drilling holes for components, and applying the solder mask and silkscreen.
  • PCBA: Starts with a fabricated PCB and involves additional steps such as applying solder paste, placing components on the board, soldering (typically through reflow soldering for SMT or wave soldering for THT), and conducting thorough inspections and testing.

Functionality:

  • PCB: By itself, a PCB cannot perform any electronic functions. It is a platform waiting to be populated with components.
  • PCBA: Represents a complete electronic circuit capable of performing the intended functions. It is the final product used in electronic devices.

Cost and Time:

  • PCB: Generally less expensive and quicker to produce than a PCBA, as it involves fewer materials and processes.
  • PCBA: More costly and time-consuming to produce due to the additional steps of sourcing components, assembly, and extensive testing required to ensure functionality.
Blue-circuit-board-with-various-electronic-components.

How to Choose a PCB or PCBA Manufacturer?

Picking the right PCBA manufacturer is no simple matter. A manufacturer’s ability to deliver quality products in time will determine the quality and performance of the products you develop on your end. 

Prior to reaching out to a manufacturer for a quote, take the time to assess their manufacturing capabilities and see if they can handle the production volume you require. It wouldn’t be wise to go to smaller manufacturers who don’t have the equipment to handle such a demand, or the labor. 

Once all these specifics have been worked out and you’re confident in their ability to produce PCBAs to your required volume, it is time to start narrowing your list down by production quality. Test sample PCBAs thoroughly and ask if engineers already have a working prototype similar to what you need. 

This is to ensure you don’t meet any design or functionality issues in your actual order. High quality materials won’t amount to much if the actual circuit design can’t live up to your demands.

Electromagnetic issues in your PCBAs will also cost you money and resources, along with anything else that can go wrong with these parts. 

While quality testing can be time-consuming and sometimes expensive, it is absolutely necessary to opt for a manufacturer who takes it seriously. 

PCBA assembly costs will also increase with the more layers there are on your PCBs. The process to manufacture PCBAs is quite complex already, and additional layers on your PCBs will only give manufacturers more room for error, and take more time to build, test, and assemble. 

Lastly, it is extremely important to work with a manufacturer who takes the job seriously, and cares about ensuring all your needs are met. Opt for someone who is transparent about their manufacturing process, their quality testing processes, and more. For more comprehensive insights, refer to Comprehensive Guide to PCBA Testing.

More factors that will influence the final cost of PCBA manufacturing will be the size, weight, design, and intended function of the PCBAs.

Article written by Alice Lee