PCB Assembly Technologies

The most common assembly technologies used in PCBA include surface mount technology (SMT) and through-hole technology (THT). These technologies are used to mount electronic components onto a PCB and create a functional circuit.

Surface Mount Technology (SMT)

SMT is the most widely used assembly technology in the PCBA industry. It involves mounting electronic components directly onto the surface of the PCB. The components used in SMT are smaller and lighter compared to through-hole components, making it possible to create smaller and more compact PCBs. SMT components are typically soldered onto the PCB using solder paste, which is applied to the PCB pads before the components are placed. The PCB is then heated to melt the solder paste and create a strong electrical connection between the components and the PCB.

Through-Hole Technology (THT)

THT is an older assembly technology that involves mounting electronic components through holes drilled in the PCB. Through-hole components have leads that are inserted into the holes and soldered on the opposite side of the PCB. This technology provides a stronger mechanical connection between the components and the PCB, making it suitable for applications that require high durability and reliability. THT components are typically larger and bulkier compared to SMT components, which can limit the size and compactness of the PCB.

Mixed Technology

In some cases, a combination of SMT and THT is used, known as mixed technology assembly. This allows for the use of both SMT and THT components on the same PCB, taking advantage of the strengths of each technology. For example, SMT components may be used for smaller and more densely packed components, while THT components may be used for larger and more robust components.

Other Assembly Technologies

There are also other assembly technologies used in PCBA, such as Ball Grid Array (BGA), Chip-on-Board (COB), and Flip Chip. BGA is a type of SMT where the electronic components have solder balls on the bottom instead of leads. COB involves directly mounting bare semiconductor chips onto the PCB without using a separate package. Flip chip technology involves mounting the bare semiconductor chip face-down onto the PCB. Each of these technologies has its own advantages and applications.

You should consider the specific requirements of your project when selecting the appropriate assembly technology. Factors such as component size, space constraints, durability, and electrical performance should be taken into account. Consulting with an experienced PCB assembler can help you determine the best assembly technology for your needs.

Files You Need for PCBA Manufacturing

In order to ensure a successful PCBA manufacturing process, there are several files that you need to provide to the manufacturer. These files include the Bill of Materials (BOM), Gerber files, and the First Article Test (FAT) report.

Bill of Materials (BOM)

The BOM is an Excel sheet that lists all the necessary components for the PCBA. It is essential to choose a reliable manufacturer who thoroughly inspects the BOM to ensure that the correct components are used during assembly. 

Gerber Files

The Gerber files, on the other hand, contain the information needed to fabricate the PCB and the necessary SMT stencils for assembly. These files provide the manufacturer with a detailed representation of the PCB layout, including the copper traces, pads, and other features.

First Article Test (FAT) Report

In addition to the BOM and Gerber files, the FAT report is also crucial for the PCBA manufacturing process. The FAT is a test that helps identify any potential glitches or issues before mass production. During the test, a technician uses a probe to measure parameters such as resistance and voltages on every device of the PCBA. The test results are then analyzed, and a test report is created for the client to review. Once the client approves the batch manufacturing based on the test report, production of the PCBAs begins.

Select the Electronic Components for Your PCBA

When selecting electronic components for your PCBA, there are several important parameters to consider for optimization. Here’s an enhanced guide to help you make informed decisions:

Through-Hole or SMDs

Choose between through-hole or Surface Mount Devices (SMDs) based on the mounting process and the complexity of the assembly steps. This decision can impact the completion process and overall efficiency.

Component Availability

Verify the availability of components before making your selection. Choosing components that are readily available can streamline the manufacturing process and prevent delays.

Moisture Resistance

Avoid selecting components that are susceptible to moisture damage. Improper soldering of moisture-sensitive components can lead to circuit failures or component explosions.

Temperature Tolerance

Opt for components that can withstand high temperatures, ideally up to 80 degrees Celsius. Choosing temperature-sensitive components can result in circuit connection failures or damage.

X-Ray Sensitivity

Consider the sensitivity of components to X-ray radiation. Some PCBA manufacturers use X-ray testing for quality control purposes. Components that are sensitive to X-ray radiation may be damaged during the testing process.

Analyze the Cost of PCBA

Collaborating with your PCBA manufacturer and design team to identify cost-saving opportunities and optimize your budget while ensuring the quality and functionality of the final product is critical for every PCBA project.

Analyzing the cost of PCBA involves considering various factors that contribute to the overall cost. These factors include labor costs, tooling and setup charges, turnaround time, quantity, technology, and packaging. Let’s take a closer look at each of these factors:

Labor Costs

The cost of labor plays a significant role in determining the overall cost of PCBA. This includes both human labor and automated factory labor. Labor costs can vary depending on the country where the manufacturing takes place. Some countries may offer cheaper labor, but it’s important to consider the quality expectations associated with those labor costs.

Tooling and Setup Charges

Custom shapes and builds may require additional tooling and setup, which can add to the overall cost of PCBA. In contrast, standard PCB designs can help avoid these setup charges, resulting in cost savings.

Turnaround Time

The time required to complete the PCBA process can impact the cost. Factors such as the time of the year, country of manufacturing, customer expectations, and more can influence the turnaround time. Expedited shipping or extra work time may incur additional costs.

Quantity

The quantity of PCBA units required can affect the cost. Higher volumes often lead to economies of scale, resulting in lower unit costs. Customers usually need to decide and balance between quantity and cost-effectiveness.

Technology

The technology used in PCBA, such as Surface Mount Technology (SMT) or Through-Hole Technology, can impact the cost. SMT, for instance, is a highly automated process that can save costs compared to other technologies.