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  • Writer's picturePhillip Tran

PCB Construction and Assembly Intro

Electronic components are found all around us in every aspect of our daily life. From advanced technological devices to common consumer products, most electronics need a central system of communicating instructions to make them operate. This communication is typically accomplished with a printed circuit board or PCB.

Printed circuit boards are typically easy to identify. They come in various sizes of green boards with copper segments and lines that are inside disassembled electronic equipment. These boards are constructed from fiberglass, copper, and other metal components. Epoxy holds the components together, and a solder mask provides insulation. That distinctive green hue originates from this solder mask.

Traces are the copper lines that link connectors and components electrically on the board. The traces allow for communication between the components; without them, the assembled PCB would not function. No matter the size of the PCB the traces can go from direct lines to intricate pathways allowing direct connection.

As impressive as the board is, it is the strategic placement of the components that allows it to function. An assembled PCB refers to one after it has all of the components installed on it, while PCB assembly, or PCBA, refers to the steps and technology that make up the process. At iTech eServices, we employ innovative machinery and skilled technicians to efficiently assemble prototypes and low to medium volume, high mix production.

There are a variety of methods for creating a final board. For most manufacturers, it is an integrated approach of both technitian aided steps and autonomous machine operations. Below, we've broken down each stage of the PCBA process so you can better comprehend it from beginning to end.

Constructs and Variations of PCBs

The initial board is made up of many layers and is the base for the PCB. Each aspect of the board's makeup is essential to the final components' ability to work properly.

• Substrate: A PCB's foundational component. It ensures the stiffness of the PCB.

• Copper: Each functional side of the PCB is covered with a thin layer of conductive copper foil, either on both sides for double-sided PCBs or just one side for single-sided PCBs. This stratum contains copper traces.

• Solder mask: The solder mask, placed on top of the copper layer, gives each PCB its distinctive green hue. The solder mask insulates the copper traces and other conductive materials to prevent accidental contact, which can cause a short. This insulation from the solder allows everything to function properly. Solder is applied through holes in the solder mask to adhere the components to the board. The solder mask is essential to preventing unintended connection of components.

• Silkscreen: The top layer of a PCB board is a white silkscreen print that adds characters and symbols to the PCB as labels on this layer.

Except for the substrate, these components and materials are largely the same for all PCBs.

Various Types of PCBs

• Rigid PCB: The most common PCBAs utilize rigid PCB bases. A stiff PCB's solid core gives the board its rigidity and thickness. These rigid PCB bases are made of a variety of substances. The most used material is fiberglass, sometimes known as "FR4". Epoxies and phenolics, which cost less to produce than FR4, are used to create less durable PCBs.

• Flexible PCB: Compared to its more rigid competitors, flexible PCBs allow for more possibilities of applications when a PCB has to fit within a particular design build. Most of these boards are built of a flexible, high-temperature plastic called Kapton.

• Metal Core PCB: If a board utilizes more heat-sensitive components, then a Metal Core PCB can be used to increase heat dispersal. Compared to the standard FR4 board boards with a metal core, tend to disperse heat more effectively.

During the assembly process, there are two main methods of adhering components to a PCB, Surface Mounted Technology and Thru-Hole Technology. Surface Mounted Technology, referred to as SMT, is used for small, delicate parts such as resistors and diodes. SMT is typically utilized with integrated circuits and tiny components (ICs).

Thru-Hole Technology, referred to as THT, is a method effective for mounting components that require leads or wires to be threaded through holes in the board. These leads are then soldered on the board's opposite side. On PCBA's that combine bulky components like capacitors and coils, THT is utilized.

Design factors and prototype analysis effect which processes and technologies are needed. Then the final assembly for manufacturing can be strategized for utilization of THT, SMT, and mixed technologies. Working with professionals experienced in prototyping and high mix, low to medium volume production, like iTech eServices, is essential to determining the best approach to your project's PCB assembly.


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