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What’s The Difference Between PCB and PCBA


Introduction





As we head towards the 5G era, we shouldn't underestimate the future of the electronics industry. Circuit boards, sometimes called the "mother of electronic products," are widely used in many applications. Those applications include communications, computers, consumer electronics, industrial control, automotive electronics, medical equipment, aerospace, and more…

The field is an indispensable part of modern electronic information products. But, do you know what "PCBA" stands for? What are the characteristics of PCBA?

In this article, PCBasic will take you on a journey to understand the difference between PCB and PCBA. We will appreciate what PCB is and the production process of PCBA.



what is pcb



What Is PCB




Let's start by understanding what PCB is. The full name of PCB is the Printed Circuit Board, and PCB manufacturers fabricated it using electronic printing. For that reason, we call "PCB" a "printed" circuit board.

The most fundamental difference between PCB and PCBA is that the PCB itself is an empty circuit board. It does not contain any electronic components. It looks like a green board with dividing lines and holes. Such an open circuit board cannot work and has no function.

Considering PCBA as the core of electronics products, PCB is the carrier of this core. PCB's job is to support all the electronic components. This enables the electrical connection between different electronic components.

We constantly see printed circuit boards used in producing and manufacturing electronic products. The printed circuit board includes an insulating bottom plate, connecting wires, and soldering pads for electronic components. It functions as a conductive circuit with an insulating bottom plate.



Types of PCB boards


There are many subdivision categories of PCB. For example, the characterization of the substrate, the number of sheets and PCB layers, etc. Taking the number of layers is an example, it can be divided into:

  • single sided pcb


  • Single-sided pcb: A single-layer circuit board made of a single layer of the material substrate. 
  • Electronic components are concentrated on one side, and the wires are concentrated on the other. 
  • We consider Single-panel a simple PCB, and often we use it in LED, radio equipment, and other similar applications.




  • double- sided pcb


  • Double-sided pcb: A double-layer circuit board fabricated by laminating the laminate of the substrate with a conductive material. 
  • The wires on both sides are easily connected through vias. In relatively complex circuits, those vias interconnect both layers on the PCB. 
  • This use case is often used in automotive dashboards, lighting systems, and vending machines.






  • multilayer pcb
  • Multilayer board pcb: Multilayer PCB is an advanced version of a double-layer PCB.

To archive a double-layer PCB design, multiple layers shall stack together on both sides of the substrate. And stick together, the number of layers of the board represents the number of layers of the independent wiring layer. The common one is 4-8 layers. Or, in other words, an insulating layer placed in the middle of multiple double-layer boards.

Multilayer boards are characterized by being complex and thick. Those boards contain less electromagnetic interference. Thus, we often see them in complex devices such as mobile phones, computers, robots, automobiles, heart monitors, etc.





PCBasic can produce PCBs according to customer needs, it only need to provide manufacturing engineering drawings, CAD, and production process.

After reading the introduction to PCB, let us learn what PCBA is.



What is PCBA?



PCBA means circuit board assembly, a general term in the electronic processing industry. It mainly refers to welding blank PCBs with SMT patches and DIP plug-ins and performing quality inspection and testing on the soldered circuit boards.

If PCB is a bare board, then PCBA is a finished circuit board. A simple understanding is that PCBA equals PCB + component assembly.

The PCBA process flow is roughly divided into four significant links, namely:

  • 1. SMT chip processing.
  • 2. DIP plug-in processing.
  • 3. PCBA testing
  • 4. Finished product assembly.

In the previous two articles, we have introduced in detail what is SMT patch processing is and what DIP plug-in processing, refer to the earlier articles for more information as we move on with different topics.


PCBA Testing



pcba testing




When we talk about PCBA testing, we refer to testing the IC programming, power, current, voltage, and circuit continuity on the processed PCBA board. Those tests strictly follow the PCBA test standard and test the circuit board points according to the customer's test plan.

PCBA testing is the most critical quality control method in the entire PCBA processing process and is a vital link to strictly controlling shipments' quality.

PCBA tests mainly include:


  • 1. ICT test: test for circuit on-off, current and voltage values, fluctuation curve, amplitude, and noise.

  • 2. FCT test: Often referred to as functional testing. This test will run a function simulation test on the PCBA board, thereby discovering problems in hardware and software.

  • 3. Flying probe test: The flying probe tester uses probes to conduct electrical tests on electronic components' value and electrical characteristics.

  • 4. Aging test: Uninterrupted and continuous power-on for the PCBA board that has passed the FCT test, simulate user input and output, observe whether the PCBA board will fail during long-term and periodic work, and test the durability and stability of the product.

  • 5. Harsh environment test: Expose the PCBA board to extreme temperatures, humidity, splashing water, drop, and vibration, and obtain the test results of random samples, to infer the reliability of the entire PCBA board batch product.


The above is the standard PCBA test methods. The operation should choose different test methods according to the actual situation of the product. A PCBA processing factory with rich testing experience can spend the least time testing your products to ensure that the products have good quality and better durability.



PCBA Assembly



pcb Assembly



The assembly of the finished product is relatively simple. Once a PCBA board passes the necessary tests, we assemble it into a shell. Afterward, the PCBA will undergo a second test. The second test will simulate the user use case of the PCBA board. Once both tests passed successfully, the product is ready to be shipped to the customer.

An important thing to note: specific safety procedures shall follow between the tests. Otherwise, the product quality will get affected. Safety requirements include electrical clearances, creepage distances, and insulation penetration distances.

Clearance: The short distance measured in the air between two adjacent conductors or one conductor and the surface of an adjoining motor casing. Creepage distance: The short distance measured along the insulating surface between two adjacent conductors or one conductor and the surface of the adjoining motor casing.

The above is the main link to PCBA production. The original PCB empty board is processed into a PCBA with electronic components and electrical properties that can be used for operation. Once the process is over, the simple PCBA board will turn into a final product.



Summary


The entire PCBA production process is interlinked. This requires PCBA processing plants to obey and control each fabrication process strictly. If you are looking for a turnkey printed circuit board assembly supplier that can maintain product quality, you can consult PCBasic.

PCBasic is an intelligent production factory. For the past 15 years, we have continuously invested in technology and quality management while constantly innovating. This is negligible in small and medium-sized PCBA processing factories because the cost of doing so isn't affordable.

PCBasic has been insisting on doing so because we believe that in the era of big data – intelligent electronic control can provide customers with the best product processing services.



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