What is PCBA?
PCBA stands for Printed Circuit Board Assembly, it refers to circuit boards assembled with electronic components such as diode, transmitter, capacitors, resistors, and ICs with SMT, DIP, and soldering assembly technology. All electronic devices have PCBA, and electronic devices are everywhere. They range from smartphones to microwave ovens and from laptops to cars.
It is a technology that mounts electronic components on the surface of a PCB directly. SMT is suitable for assembling tiny and sensitive components such as transistors onto the circuit board. This technology helps to save more space as there is no need to make drilling that also benefits to speed up the production progress. In addition, by applying surface-mount tech, the electronic components can be assembled on the surface closely, so both sides of the PCB can be utilized.
Another method is Thru-Hole Technology, which is used by people earlier than SMT. THT is a technology that the electronic components are plugged into the circuit boards through holes, and manufacturers need to solder the extra part of wire on the board. It takes more time than SMT, but it still has some advantages. For example, by using through-hole technology, the electronic components are bonded to the board strongly. Therefore, this technology is suitable for large electronic components such as coils and capacitors, which can withstand high power, high voltage, and mechanical stress.
The PCBA Manufacturing Process in MOKO
Before we start learning the manufacturing process, let’s talk about some basic knowledge about PCBs. All types of PCBs contain the following layers:
- Substrate: A primary material for PCBA manufacturing that gives the rigidity to the circuit board.
- Copper: Each side of all circuit boards contain a conductive layer of copper foil.
- Solder Mask: Green or Yellow color of PCB is due to solder mask. Why we use it? You will learn in detail ahead!
- Silkscreen: This is the uppermost layer of all PCBs. It contains components or board information in textual or symbolic form.
Let’s understand the manufacturing process of PCBA in details:
Solder Paste Stenciling
First and foremost, the PCBA company applies a solder paste to the printed circuit board. In this process, you need to put solder paste on certain portions of the board. That portion holds different components.
The solder paste is a composition of different tiny metal balls. And, the most-used substance in the solder paste is tin i.e. 96.5%. Other substances of solder paste are silver and copper with 3% and 0.5% quantity respectively.
The manufacturer mixes paste with a flux. Because flux is a chemical that helps solder in melting and bonding to the board surface. You must apply solder paste at the precise spots and in the right amounts. The manufacturer uses different applicators for spreading paste in the intended locations.
Pick and Place
After the successful completion of the first step, the pick and place machine has to do the next job. In this process, manufacturers place different electronic components and SMDs on a circuit board. Nowadays, SMDs are accountable for non-connector components of boards. You will learn how to solder these SMDs on the board in the upcoming steps.
You can use either traditional or automated methods to pick and place electronic components on the boards. In the traditional method, manufacturers use a pair of tweezers to place components on the board. Contrary to this, machines place components on the right position in the automated method.
After placing the components in the right place, manufacturers solidify the solder paste. They can accomplish this task through a “reflow” process. In this process, the manufacturing team sends the boards to a conveyor belt.
The conveyor belt has to pass from a large reflow oven. And, the reflow oven is almost similar to a pizza oven. The oven contains a couple of heaters with different temperatures. Then, the heaters heat the boards at different temperatures to 250o C. This temperature converts the solder into solder paste.
Similar to heaters, the conveyor belt then passes through a series of coolers. The coolers solidify the paste in a controlled manner. After this process, all electronic components sit on the board firmly.
Inspection and Quality Control
After mounting the components in the reflow process, you need to inspect the board for flaws. In this process, manufacturers also test for the functionalities of the board. During the reflow process, many boards come with poor connections or become short. In simple words, there can occur a lot of connection problems during the previous step.
So there are different ways to check the circuit board for misalignments and errors. Here are some remarkable methods of testing:
Even in the era of automated manufacturing and testing, manual checking still has significant importance. However, manual checking is most effective for small scale PCB PCBA. Therefore, this way of inspection becomes more inaccurate and impractical for large scale PCBA circuit boards.
Besides, looking at the miner components for so long is irritating and optical fatigue. So it can lead to inaccurate inspections.
Automatic Optical Inspection
For a large batch of PCB PCBA, this method is one of the finest options for testing. In this way, AN AOI machine inspects PCBs using plenty of high-powered cameras.
These cameras cover all angles to inspect different solder connections. AOI machines recognize connections’ strength by the reflecting light from solder connections. The AOI machines can test hundreds of boards in a couple of hours.
It is another method for board testing. This method is less common but more effective for complex or layered circuit boards. The X-ray helps manufacturers to examine lower-layer problems.
Using the aforementioned methods, if a problem exists, the manufacturing team either sends that back for reworking or scrapping.
If the inspection finds no mistake, the next step is to check its workability. It means testers will check if it works as the requirements or not. So the board might need calibration to test its functionalities.
Insertion of Through-Hole Component
The electronic components vary from board to board depending on the type of PCBA. For example, the boards might have different types of PTH components.
Plated through-holes are different types of the hole in the circuit boards. By using these holes, components on circuit boards pass the signal to and from different layers. PTH components need special types of soldering methods instead of using only paste.
This process is very simple and straightforward. At a single station, one person can easily insert one component into an appropriate PTH. Then, the person will pass that board to the next station. There will be many stations. At each station, a person will insert a new component.
The cycle continues until all components are installed. So this process can be lengthy that depends on the number of PTH components.
It is an automated way of soldering. However, the process of soldering is completely different in this technique. In this method, the boards pass through an oven after putting on a conveyor belt. The oven contains molten solder. And, the molten solder washes the circuit board. However, this type of soldering is almost not practicable for double-sided circuit boards.
Testing and Final Inspection
After the completion of the soldering process, PCBAs pass through the final inspection. At any stage, manufacturers can pass circuit boards from the previous steps for the installation of additional parts.
Functional testing is the most common term used for the final inspection. In this step, testers put the circuit boards through their paces. Besides, testers test the boards under the same circumstances in which the circuit will operate.
For example, testers test the board on different voltages, signals, and currents. If boards show fluctuation or unwanted behavior, the circuit boards fail the test. So manufacturers can recycle or scrape the circuit boards.
How to Design and Select the Electronic Components for Your EMS PCBA Optimization?
The design of the circuit depends on the circuit parameters. Before starting the design, the manufacturing team looks for general and optimal choices. To get precise and high-quality results, you should go for optimal choices.
For example, if someone chooses a component footprint as a design parameter. Then, the generic choice for the manufacturer will be a general package footprint. However, you can ask for the specification of a component manufacturer for footprint as an optimal choice.
Minimum spacing can be a generic choice for spacing and clearance design parameters. However, maximum spacing can be the optimal choice for spacing and clearances.
But who will decide the optimal choice? Different experts of the circuit board’s manufacturing companies decide or suggest the optimal choice.
Electronic Components Selection
Here are some important parameters to select different electronic components for EMS PCBA optimization:
- Through-hole or SMDs: Both contain the different mounting process. Besides, there are different steps need to complete the process. So you can reduce the completion process by choosing any of the two.
- Verify Component Availability: Choose components wisely. Because more components can extend the steps and make the process complex as well.
- Component Selection: Never choose those components that can easily take on moisture. If you fail to solder them properly, it can lead to the explosion of components.
- Temperature Bearable Components: Try to select those components that can bear up to 80-degree centigrade. Choosing temperature-sensitive components can result in breaking of the circuit connection.
Different China PCBA manufacturers use x-ray for testing purposes. So components mustn’t be sensitive to x-ray radiations. Otherwise, an x-ray can damage the components.
Why Choose MOKO Technology?
It is very difficult to choose the best of the best PCBA company for your valuable products. Your single wrong decision can lead you to the massive loss. Because the circuit board is the heart of electronic devices. So its failure is the failure of the circuit board.
Are you looking for a professional and trustworthy PCBA company? MOKO Technology is the finest option for you. They are one of the leading China PCBA manufacturers. They provide excellent quality boards at the lowest possible price.
The company offers a very touchable purchasing process for the clients. That’s why they don’ have any hidden charges.
The company has many professional and highly trained workers. So you will buy circuit boards built under the scrutiny of expert engineers. So they give valuable advice to the customers and assist them in choosing suitable boards of their needs.
MOKO Technology designs all types of circuit boards according to the requirements of clients. For huge order, you will get a special discount offer. Do you have an idea? You can actualize that with the help of MOKO Technology!
Excellent PCBA Production Capacities
Before placing an order, you must be familiar with the production capacities of a company. The facilities at MOKO are well equipped, below are listed some of our equipment that helps us to deliver high-quality products effectively:
Manufacturing and Testing Machines for PCBA
Many useful machines make the manufacturing process very straightforward and easy. Below are some remarkable machines:
- Machine for Solder Paste Inspection: The PCBA factory uses this machine to inspect circuit boards after applying solder paste. It tells the manufacturing team whether paste is at the precise location on the board or not.
- Glue Dispensing Machine: Makers use this machine to apply many dots of glue on the circuit boards before placing the components.
- Pick and Place Machine: After placing glue dots, companies use this machine to pick and place different components on the circuit board.
- Reflow Soldering Machine: It is another important machine for making a PCBA circuit board. The most important part of this machine is a conveyor belt. You have already learned about the conveyor belt in the previous section.
- Wave Soldering Machine: Manufacturers use this machine as an alternative option to the previous machine. When manufacturers need to pass circuit boards from the wave of molten solder instead of simple heaters, they utilize this machine.
Complete PCBA Production Lines
Whatever your requirements are, MOKO Technology is capable to configure PCBA lines for you with 5 SMT lines, 3 DIP production lines and another 3 production lines for the enclosure assembly. Present your requirements and get complete guidance from the experts of the company. So it is straightforward for you to get a quote on SMT lines according to your needs.
The Scope of Our PCBA Service
This company offers all types of circuit boards range from through-assembly to SMT surface mount assembly. Further, you can find prototype PCB assembly to short-run project assembly in our PCBA factory. You can find low to medium to high volume circuit boards at a fair price.
• SMT PCB assembly
• Through-hole PCB assembly
PCB Design and Layout
With over 13 years of experience, the company provides premier PCBA services and is renowned for its excellent PCB design and layout capabilities.
MOKO Technology stands out among all China PCBA manufacturers and in the world. They have a quick turn project. Besides, they are adept in the Complex PCB Project. If you have a price-sensitive project, you should consult this company. In nutshells, you can ask for the least simple to the most complex design. And, the company will provide you 100% satisfactory design within the due date. Besides, the company offers leaded and lead-free PCB assembly. You can also utilize the water clean or no-clean flux option.