PCB is the most common name but may also be called printed circuit boards. It is a board that has lines and pads that connect various points together. In the picture above, there are traces that electrically connect the various connectors and components to each other. A PCB allows signals and power to be routed between physical devices. Solder is the metal that makes the electrical connections between the surface of the PCB and the electronic components. Being metal, solder also serves as a strong mechanical adhesive.

Printed circuit boards form the very core of all electronic and many electrical devices, they provide the fuel that allows them to function at desired standards. The earlier simple designs have evolved into complex, sophisticated circuit boards that are used to power an increasing variety of highly advanced and complex machines and equipments. As gadgets become more and more integrated into every aspect of human life, the need for PCB prototyping becomes even more important than ever. In some human applications powered by gadgets, like the healthcare the margin for error is nil, which increases the significance of PCB assembly and prototyping.

Printed circuit board assembly is essentially referred to the process of assembling or soldering electronic components onto a circuit board. The Assembling of a circuit board is not the same as manufacturing a circuit board. A circuit board is only manufactured once the design, prototyping and testing phases are over, but the assembling a circuit board happens both during the prototyping phase as well as post manufacturing of the circuit board.

The following is  some items critical for assembling a circuit board:
Circuit board
Electronic components for soldering
Equipments for soldering
Materials like solder paste and wire
Equipment for testing

There are several steps in the assembly of a PCB prototype, the most important ones being
Drawing up an Assembly Diagram
Adding Solder Paste
Component placement onto board
Board Reflow
Inspection
Final Assembly
Cleaning

Prototyping has always been an important step in any product development process. PCB prototyping is particularly important because different applications require different kinds of PCB assembly and unless you assemble a prototype to conduct an actual functionality test, you are likely to end up with a sub optimal product. PCB prototyping till some time back was a costly and time consuming process mainly because the assembly process had to be outsourced. But technological advancements have made it possible to conduct PCB assembly for prototyping on-site making the whole process significantly faster and far more cost effective.