PCB versus PCBA: What’s the Difference and How to Choose?

PCB e PCBA são os dois termos mais comuns na indústria eletrônica. Embora a diferença entre eles seja apenas uma letra, eles representam coisas diferentes. O nome completo do PCB é Placa de Circuito Impresso, que se refere a uma placa em branco sem quaisquer componentes eletrônicos montados. PCBA significa Montagem de Placa de Circuito Impresso, que se refere a uma placa que é montada com vários componentes e pode atingir determinadas funções. PCBA é construído com base em PCB. Neste blog, iremos apresentá-los separadamente e comparar suas diferenças em detalhes.

O que é um PCB?

Uma placa de circuito impresso (placa de circuito impresso) is a thin and flat board made of non-conductive materials. It serves as a base for the mechanical support and electrical connectivity of electronic components. o Substratos de PCB, typically made of non-conductive materials like fiberglass or epoxy resins, allow the etching or printing of conductive copper pathways over their surface. These copper pathways are known as traces, electrically linking together various componentes da placa de circuito que são soldados ao PCB.

What Are the Different Types of PCBs?

De acordo com o número de camadas condutoras de cobre, pode ser classificado como:

PCBs de um lado have copper tracks on only one side of the insulating substrate, offering low-cost, simple solutions for basic circuits.

PCBs de dupla face have conductive tracks on both sides of the substrate, enabling more compact designs than single-layer PCBs.

PCB multicamada have multiple copper layers bonded together, allowing much denser and more complex circuitry. They are ideal for advanced electronics and allow high-speed signals.

Com base nos diferentes materiais utilizados, printed circuit boards can also be categorized as metal PCB, PCB fr4, PCB cerâmico, e assim por diante.

Para saber mais conhecimento sobre os tipos de PCB, fleia mais: Quantos tipos de PCB existem?

O que é um PCBA?

Um PCBA (Montagem da placa de circuito impresso) refers to the result of soldering all the necessary electronic components on the blank PCB, and then the assembled board becomes a fully functional circuit. além do que, além do mais, it also indicates a process of installing the components on the circuit board.

Three Main PCB UMAmontagem Métodos

There are three methods that most PCBA manufacturers use for PCB assembly. The following is a brief introduction.

Tecnologia de montagem em superfície (SMT)

SMT is an automated process that can directly mount componentes de montagem em superfície onto the PCB surface without drilling any holes. These SMT components are small and can be packed in high density to make the circuit board compact.

Tecnologia Thru-Hole (THT)

THT is a method of inserting components with pins into drilled PCB holes. And then the protruding leads are soldered on the opposite side. These THT components are large and require manual assembly.

Mixed-technology

Mixed technology combines the advantages of SMT and THT. It can solder small SMT and large Componentes THT on the same PCB.

Qual é a diferença entre PCB e PCBA?

Though often used interchangeably, PCB and PCBA represent different stages in electronics manufacturing. To clear out the confusion between them, here we expound on the 5 major differences.

1. Composição and Function

As for PCB, it is mainly composed of these 4 camadas:

• The substrate euayer is usually made of FR-4, which provides rigidity as well as insulation.
• Thin copper foil layers are bonded to the substrate to form conductive paths for the signal.
• The solder mask layer is a protective polymer coating that prevents short circuits and corrosion while leaving solderable openings exposed.
• The silkscreen layer with printed labels provides assembly and component placement instructions.

As for PCBA, it’s a complete functional unit, Incluindo:

• PCB serves as a base and is ready for installing components.
• Electronic components such as capacitors, transistores, and resistors are mounted onto the board with SMT or THT, each serving various purposes.
• Traços are thin conductive channels on the PCB surface to carry electrical signals.
• Vias are tiny holes drilled into the PCB to link various layers in multilayer PCBs, enabling signals to transmit between them.
• Solder colar forms electrical and mechanical bonds.

2. Processo de manufatura and Machines Required

Another major difference between PCB vs PCBA is their manufacturing process:

PCB Processo de manufatura

A fabricação de PCB gira em torno da elaboração do placa de circuito desencapada em si. The manufacturing process is typically automated and marked by high precision, relying on specialized machines.

• Designers use PCB design software (por exemplo., Altium, Cadence) to assist with designing the layout.
• The unwanted copper is removed by etching machines to form traces, and copper layers are applied to the substrate by lamination presses.
• The CNC drilling machines and laser drills create vias and through-holes on the board.

PCBUMA Processo de manufatura

PCBA takes the PCB as its starting point to populate electronic components. This assembly process can be manual or automated, requiring different equipment to mount components efficiently.

• Solder paste printers apply precise amounts of solder paste onto PCB pads.
• Automatic and high-speed pick-and-place machines apply the SMD components with high precision using robotic arms.
• Reflow ovens melt the solder paste in a controlled thermal profile, solidifying strong connections. The wave soldering equipment is utilized for through-hole components.

3. Defeitos

Since the manufacturing processes of PCB vs PCBA are different, the potential defects they encounter also vary. PCB may come with these defects: excess or missing copper, over or under-etching, missing drilled holes, opens and shorts. PCBA may meet potential defects like missing or misaligned components, solda excessiva, ponte de solda, etc.

4. Teste

A bare PCB must undergo electrical verification before assembly. The fixture test involves using a special bed-of-nails fixture with probes to precisely connect to the test nodes on the PCB to test the circuit. It can also be used to test PCB pads, which is a more efficient testing method. In the flying probe test, the test points are contacted by a movable and flexible probe.

A PCBA needs to check components, de solda, funcionalidade, and long-term reliability. In-circuit test (TIC) is used to detect PCB components through a fixture, easily checking manufacturing failures. The flying probe test can also be used to detect PCBA. Functional test simulates the actual working conditions of PCBA to test whether it can operate normally. The aging test simulates the long-term and periodic operation to evaluate its durability and stability. A harsh environment test exposes the assembled board to extreme temperature, umidade, drop, or vibration.

5. Tempo de produção e Custo

A fabricação de PCB é geralmente mais econômica e eficiente em termos de tempo em comparação com a montagem de PCB. Os custos de PCB são mais baixos devido ao design mais simples e às despesas com materiais. PCBA envolve custos mais elevados para componentes e processos de montagem trabalhosos. Além disso, Os prazos de entrega do PCBA são mais longos devido à integração de componentes e aos testes extensivos necessários.

Aspects	PCB	PCBA
Definição	A bare circuit board without components	A fully assembled circuit board with all required components
Componentes	Nenhum	All necessary components are assembled
Function	As the foundation for electronic component assembly	As a complete electronic module ready for operation
Processo de manufatura	Designing PCB layout, gravando vestígios de cobre, adding insulating layers, and drilling holes	Applying solder paste, colocação de componentes, and soldering
Machines Required	Design software, etching machines, lamination presses, CNC drilling machines, and laser drills	Solder paste printers, pick-and-place machines, reflow ovens, and wave soldering machines
Assembly Techniques	Not needed, as no components are installed	SMT, THT, and mixed technology
Packaging Methods	Vacuum packaging	Packaging with compartments or anti-static packaging
Manufacturing Defect	Excess or missing copper, over or under-etching, missing drilled hole, opens and shorts	Missing or misaligned components, solda excessiva, ponte de solda
Teste	Fixture test, teste de sonda voadora	ICT test, Functional test, teste de sonda voadora, aging test, harsh environment test
Custo	Mais baixo	Mais alto
Tempo de espera	Shorter	Longer
Usar	Used for prototyping	Used in final electronic products

Applications of PCB and PCBA

Eletrônicos de consumo – From smartphones to TVs, PCB and PCBA are almost ubiquitous today, integrating into our daily used devices.

Eletrônica automotiva - With the popularity of electric vehicles, PCB and PCBA have become indispensable and key parts. They play a big role in battery management, autonomous navigation, etc.

Controles Industriais - PCB and PCBA act as the “heart” of the mechanical system, providing power and control capabilities. They are widely used in smart sensors, dynamic motor drives, and programmable logic controllers (PLCs).

Dispositivos médicos - The equipment’s accuracy and dependability are of utmost importance in the medical field. Whether it is a simple heart rate monitor or a complex MRI scanner, high-precision surgical instruments, all rely on high-quality PCB and PCBA.

Aeroespacial e Defesa - This is a demanding field where PCB and PCBA must meet extremely strict quality and technical standards. They are often used in a variety of critical electronic systems, from cockpit instrumentation to missile guidance systems.

IoT Devices – The rapid advancement of IoT is accelerating innovation in smart homes, dispositivos vestíveis, and industrial sensors. Their core is the compact PCB and PCBA, silently supporting the normal operation of these IoT devices.

PCB versus PCBA: Quando usar PCB? Quando usar PCBA?

The following are recommended options in different situations:

When to Usar PCB:

• If you only need the foundational circuit board to build upon later, a PCB is likely suitable. It allows for customization and component integration flexibility.
• Bare PCBs make sense for low-volume prototyping.
• Para projetos DIY simples com poucos componentes que você mesmo deseja escolher, the PCBs offer prototyping flexibility.

Quando usar PCBUMA:

• If you wish to have a ready-to-go electronic assembly without needing to source and solder components, um PCBA é preferível. It can directly integrate into devices.
• For complex projects with tight timelines, PCBAs may be the best option to accelerate development and save assembly time.
• PCBAs have economies of scale, which make them ideal for mass production.

Palavras Finais

Knowing the differences between PCB vs PCBA is very important for those working in the electronics industry. The difference among them affects many factors like production, Compras, Projeto, and cost control. Reach out to us for specialist help in your upcoming project and also to receive assistance when determining whether you need PCB or PCBA services.

FAQs about PCB and PCBA

How are PCB, PCA, and PCBA different from one another?

PCA (Montagem de Circuito Impresso) is another term for PCBA, but it is rarely used. A PCA (or PCBA) is a PCB that has been filled with electrical components, and a PCB is a bare circuit board.

O que makes a PCB and PCBA manufacturer reliable?

Find suppliers who have:

• Choose a manufacturer with industry certifications like UL, IPC, e ISO.
• With established technical capability like SMT, teste (AOI, X-ray), and DFM feedback.
• Committed to on-time delivery without delay.

Can I assemble components on the PCB myself?

sim! If you are building a prototype or repairing a circuit board, you can assemble it yourself. Here is what you will require: proficient skills and the necessary tools, like a soldering iron, solda, tweezers, fluxo, etc.

What are the materials commonly used in PCB manufacturing?

Here are some commonly used materials suitable for different types of PCBs.

• FR-4: Most typical material, offering a low-cost solution for standard PCB.
• Poliimida: Ideal for flexible PCB or rigid-flex PCB, providing high thermal stability and flexibility.
• PTFE: Particularly well-suited for RF and microwave applications, giving low dielectric constant and reduced signal loss.