What Is PCB Assembly?

PCB assembly is a complex process that involves the building of circuit boards. Circuit boards are typically made from plastic and require a high level of precision. The process of assembly is often performed by hand. However, some circuit boards are so intricate that a machine is required to handle them. This process can be costly and time-consuming.

Printed circuit board assembly

Printed circuit board assembly is an essential process in the creation of electronic devices. It is a process in which printed circuit boards are placed onto a non-conductive substrate. Then, components are attached to the PCB. Depending on the type of board and its application, different processes are used.

One of the most important factors in PCB assembly is the component footprint. Ensure the footprint matches the datasheet exactly. Otherwise, the component will be positioned improperly and receive uneven heat during the soldering process. In addition, a wrong footprint can cause the component to stick to one side of the PCB, which is not desirable. Moreover, the wrong land pattern can cause problems when using passive SMD components. For example, the width and magnitude of the tracks connecting pads can affect the soldering process.

The process of PCB assembly starts with printing a circuit board design onto copper-clad laminate. This is followed by etching the exposed copper to leave a pattern. Upon placement of the components, the circuit board is then placed on a conveyer belt. After the board is placed in a large over, it undergoes reflow soldering. Reflow soldering is an important step in PCB assembly. The reflow process involves placing the circuit board on a conveyor belt, and then putting it inside a heated chamber. During this time, solder melts and shrinks.

Techniques

There are several different techniques for PCB assembly. One of these techniques is automated optical inspection, which incorporates a machine with cameras to examine the boards from various angles and detect any errors. Another technique is visual inspection, which involves a human operator checking the boards manually. These techniques are useful for PCBs made in small quantities, but they have their limitations.

Orienting the parts in the same direction is another technique for making the PCB assembly process faster and easier. This method helps minimize the chances of cross-connecting components, which can lead to soldering problems. Another technique is placing the edge components first. The reason for this is to guide the layout of input connections on the board.

Costs

The costs of PCB assembly vary greatly between companies. This is because the basic materials used to manufacture PCBs are expensive. In addition, some companies will charge much more than others for the same PCB assembly services. However, the quality of the finished product remains unaffected. So, if you are unable to afford the high cost of PCB assembly, you can always look for cheaper alternatives.

PCB assembly costs are dependent on the volume of PCBs that you need assembled. Low-volume orders will incur higher costs, while medium-sized orders will incur lower costs. Moreover, the quality of the design and components used in the PCB assembly process will also play a role in determining the overall cost.

Downfalls of manual pcb assembly

Manual PCB assembly is a labor-intensive process that requires skilled technicians. It also takes a lot of time and has high risk of human error. For this reason, manual assembly is not recommended for large-scale PCB assembly projects. It is also not an ideal option for some components, such as fine-pitch pins and dense SMT parts.

Another disadvantage of manual PCB assembly is the lack of automation. Even the most seasoned hands will struggle to achieve the same level of precision as a machine. It is also difficult to achieve consistent and residue-free soldering. As a result, hand-made boards have inconsistent quality. Moreover, smaller components are more difficult to assemble by hand.

In-Circuit testing

In-Circuit testing (ICT) is a process in which the PCB is put through a number of steps in order to ensure that all components are properly seated. It is a very useful test, but has some limitations, such as limiting test coverage. Some PCB components are too small for this method, or have a large number of components. Nevertheless, this method can provide high levels of confidence in the build quality of the board and its functionality.

PCBAs can be tested in many different ways, including in-circuit testing, which uses electrical probes attached to specific points on the board. The probes can detect component failures such as lifts, shifts, or bad soldering. They can also measure voltage levels and resistance, as well as other related factors.