What Is the Difference Between PCBA and PCB?
Printed circuit board (PCB)
printed circuit board assembly (PCBA)
The main difference between them is that PCB refers to a blank circuit board whereas PCBA refers to a circuit board that contains all the necessary electronic components. It is the support body of electronic components and the provider of circuit connection of electronic components. A PCB is not functional because it does not have the required components whereas a PCBA is a complete functional board. The PCBA is built on top of an existing PCB.
Simply put, the empty PCB board goes through the SMT loading and then goes through the entire process of the DIP plug-in, referred to as PCBA. It can also be understood that PCB is a circuit board without components, and PCBA is a circuit board with electronic components welded.
What Is a PCB?
PCBs are the foundation of modern electronic devices. They mechanically support and electrically connect electronic components. Since it is made using electronic printing technology, these paths are printed or engraved on the board according to the predetermined PCB design, so it is called a printed circuit board.
Before the advent of printed circuit boards, the interconnections between electronic components depended on the direct connection of wires to form a complete circuit. The circuit board itself is made of laminate materials, such as fiberglass or composite epoxy, and contains conductive paths that connect different parts of the circuit board. These paths are printed or engraved on the board according to the intended PCB design.
Today, circuit panels exist only as effective experimental tools. Among them, it is divided into 4 layers, 6 layers, and 8 layers according to the number of signal layers. Layers 4 and 6 are the most common.
PCB Substrate
The base material is generally classified by the insulating part of the substrate. The common raw materials are bakelite board, fiberglass board, and various plastic boards. PCB manufacturers generally use an insulating part composed of glass fiber, non-woven material, and resin, and then press it with epoxy resin and copper foil.
Common substrates and main ingredients:
FR-1 ─ Phenolic tissue paper (higher economy than FR-2)
FR-2 ─ Phenolic Tissue Paper
FR-3 ──Cotton paper
FR-4 ──Woven glass
FR-5 ─ Glass cloth, epoxy resin
FR-6 ─ Frosted glass, polyester
G-10 ─ Glass cloth, epoxy resin
CEM-1 ─ Tissue paper, epoxy resin (flame retardant)
CEM-2 ─ Tissue paper, epoxy resin (non-flame retardant)
CEM-3 ─ Glass cloth, epoxy resin
CEM-4 ─ Glass cloth, epoxy resin
CEM-5 ─ Glass cloth, polyester
AIN – Aluminum Nitride
SIC – Silicon Carbide
PCB Metal Coating
In addition to the wiring on the substrate, the metal coating is also the place where the substrate circuit and electronic components are soldered.
In addition, different metals also have different prices, which will directly affect the cost of production. Different metals also have different solderability and contact properties, as well as different resistance values, which also directly affect the performance of components.
Commonly used metal coatings:
copper
tin
Lead-tin alloy (tin-copper alloy)
gold
silver
Types of PCBs
The main types of PCBs include:
Single-layer PCBs are the simplest type of PCBs and are coated with a single layer of conducting material and a layer of solder mask. The PCB’s components are marked with a silkscreen.
Double-layer PCBs have a layer of conducting material on both the top and bottom of the board, which gives them more flexibility and a smaller size than single-layer PCBs.
Multi-layer PCBs have more than two conductive layers and are used in more complex applications.
Other common types of PCBs include flexible PCBs, rigid PCBs, and flex-rigid PCBs.
Applications
smart phone
touch panel
computer
eBook
digital camera
medical system
industrial control
data storage device
satellite system
LCD TV
LED lighting
What Is the Definition of PCBA?
While PCB refers to a blank board, a PCBA is a completed PCB assembly that contains all of the electronic components needed to make the board function as required. PCBA may also refer to the process of assembling the board with the necessary components.
The most dominant methods used by PCBA manufacturers for PCB assembly:
SMT(Surface Mounted Technology)
Surface mount technology mainly uses the placement machine to mount some tiny parts on the PCB board. The production process is as follows:
PCB board positioning
printing solder paste
placement machine placement
Reflow oven
Made inspection
With the development of technology, SMT can also mount some large-sized parts, for example, some larger-sized mechanical parts can be mounted on the motherboard.
Current Situation of PCB Industry
Since the production of printed circuit boards is in the second half of electronic equipment manufacturing, it is called the downstream industry of the electronics industry. Almost all electronic devices require the support of printed circuit boards, so printed circuit boards have the highest market share in the global electronic component products.
At present, Japan, China, Taiwan, Western Europe and the United States are the main PCB manufacturing bases.
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