PCB Assembly is a challenging aspect in the PCB industry. PCB manufacturing has different stages, of which the PCB assembly is among. Every stage requires extreme attention and care. If you are a product engineer, electronics and electrical engineer, a designer, etc. it is important you understand what PCB assembly entails.
A printed circuit board has components that enable it to function. In this guide, we will be talking about PCB assembly and every important aspect of it. We will also talk about PCB assembly USA.
What is PCB Assembly?
PCB assembly is an integral aspect of PCB manufacturing that involves the attachment of different components. This process involves getting these components embedded via a process. PCB assembly is a well-detailed yet lengthy process. This aspect requires engineers to pay careful attention to details.
A PCB that has gone through this stage is referred to as an assembled PCB. The components attached to a PCB aren’t mere decoration, they serve a purpose. A circuit board won’t function well until you mount components on it. An assembled PCB is a board with components and this process is referred to as PCB assembly.
If you take a close look at a bare board, you will see copper lines. These copper lines are known as traces. They link components and connectors to each other. The process of a PCB assembly is a straightforward one. It requires various manual and automated steps. With every step, a PCB producer has both automated and manual options to choose from.
PCB Assembly Process
Before adding components to a board, you need to add solder paste. You attach this paste to parts of the board where solder is needed. These parts are component pads. This solder paste can be seen as a mixture of small solder grains and flux.
With the solder screen positioned onto the board and placed in the right position, a runner squeezes a small amount of solder paste via the holes and onto the board. The solder screen has holes on the solder pads and solder can be added on the solder pads only. You have to be careful of the amount of solder you add. This will ensure the joints have the appropriate amount of solder.
Pick and place
The circuit board which already has solder paste undergoes the pick and place process. In this step, the board is moved to automated machines for the mounting of components on their pads. The machine which is loaded with components picks the components from other dispensers and positions them in the right place on the board.
The solder paste holds the components on the board. This paste is enough to keep the components in place as long as the board isn’t jolted. In some cases, the pick and place automated machines add glue to keep the components on the board firm. Engineers inspect the board after mounting the components. This helps to ensure that all placements are correct before you begin soldering.
In this stage, the circuit board passes through the soldering machine. Soldering is the commonest approach for PCB assembly. Reflow soldering is more flexible than manual or wave soldering. Most times, reflow soldering is used for most components on a circuit board.
Some boards pass through wave soldering; this process is not common in today’s PCB industry. The main problem in this stage is that components have to resist high levels of heat for a prolonged time. This is unlike manual or wave soldering.
Inspection and quality control
After the circuit boards pass through soldering machines, they will be inspected. This helps to ascertain the reliability and quality of the PCBs. Inspection can be done manually, visually, or through the use of X-Ray. Manual inspection isn’t ideal for surface mount boards.
Automated optical inspection is a better solution. There are machines that can inspect PCBs and identify misplace components, poor joints, and other errors. An X-Ray detects problems in PCB assembly. The X-Ray image helps to know the root cause of a particular defect. Experts should perform inspection and quality control.
Testing PCBs for accuracy and effectiveness is important. Although inspections are performed after each stage of the PCB assembly process, carrying out a final test is necessary. The final test is carried out to detect any mechanical errors on the PCB. After they have been tested, the PCBs are packaged in a secure box for shipping.
PCB Assembly Techniques
There are three different PCB assembly techniques for a PCB designer.
Automated PCB assembly technique
This technique uses state of the art machines. For instance, the surface mount components are positioned using a pick and place machine. Reflow soldering is used for surface mount components. In this technique, engineers use automated solder stencil to apply solder paste on the circuit board. Here, high-tech inspection machines examine and verify the quality of the PCB assembly. This technique guarantees output consistencies, efficiency, and reduces defects.
Manual PCB assembly technique
This technique is ideal for through-hole parts that require manual placement on the circuit board. Wave soldering is commonly used in this technique. It is important you know that in the through-hole process, components are placed manually on the PCB. You will then solder the leads with wave soldering.
In PCB assembly USA, this technique is ideal if you intend to produce a limited number of printed circuit boards. It depends on human input during components placement. A designer can use tweezers to pick and place the electronics. The inspection procedure is visual in this technique.
However, one of the drawbacks of this technique is inaccuracy since humans are imperfect. There can be inconsistencies in the output. That is why this technique is only ideal for the production of a limited number of boards.
Electronic devices are becoming complex with the constant development in science and technology. It is rare for PCB assembly to use just one technique. Most PCBs have SMD components and Through-hole components which require the combination of manual and automatic PCB assembly technique. Therefore, it is common to see PCB assembly that involves mixed technology.
Factors to consider when hiring a PCB assembly company
People ask questions like how can I hire a standard PCB assembly company? The truth is that there are several PCB assembly companies. PCB assembly California and PCB assembly San Jose are known for offering the best PCB assembly.
Experience: This is an important factor you need to consider. Experience is important. You definitely need a company that has gained years of experience in PCB assembly. You need to make an inquiry about the number of years the company has been operating, the type of firms it partners with, and the types of products it has manufactured. You can get these pieces of information from the company’s website or ask the representative of the company.
Customer service: Customer care is very important. The customer support service of a company shows how the company cares for its customers. The customer support service tends to any questions or complaints promptly. A professional PCB assembly company will have great customer support concerned with solving customer’s issues.