printed circuit board assembly meaning
Printed circuit board assembly (also named PCB assembly, or PCBA) is a process of installing various types of electronic components on the PCB board, connecting to conductive pathways of the board and solidified those component onto the board.
printed circuit board assembly process
Step 1: Solder Paste: Solder paste would be printed through a stainless steel stencil onto the surface of the PCB board.
Step 2: place components: Automatic machine pick up and place SMDs onto the surface of the PCB board, the place already printed with solder paste in the previous step. With this automatic pick and place machine, printed circuit board assembly work become far more efficient.
Step 3: Reflow Soldering: Printed circuit board with solder paste and SMD components would be transfer to a conveyor belt. The conveyor belt would pass the circuit board go through an oven with temperature around 480 degrees Fahrenheit (250 degree Celsius). Afte go through the oven the solder on the board would melt, then transfer the printed circuit board to an cooler to let the solder cool down and solidify again. Then the SMDs component would be fasten on the surface of the circuit board.
Step 4: Quality Inspection: Quality inspection involve to several inspection methods such as manual Checking, Automatic Optical Inspection, X-ray Inspection. The purpose is to check whether any component missing, movement, poor or lack connection.
Step 5: Inserting Through-Hole Components: Through-Hole Component with long lead, its lead must inert into the hole of the printed circuit board. The automatic machine can’t finished, so these components only can be insert into PCB hole by manually.
Step 6: Soldering Through-Hole Components: Usually through hole compontes would be soldered by manual or wave soldering machine.
Step 7: Final Inspection : The inspection would simulating normal working environment to let the board operate, let the simulated signal go through the printed circuit board, test all of its function to check whether all of them work normal. If found the defective, would take out to repair, if can repair would be scrapped.
printed circuit board assembly testing
How we control the quality of printed circuit board assembly for you, there several testing methods, we use to test PCB board quality in our production.
Flying probe testing
It is cheaper testing method. It can test diode, inductance, capacitance, resistance, shorts, opens. Though flying probe test is cheaper than ICT, but ICT is more reliable than Flying probe testing.
In-circuit testing is the most common type of testing for PCBs. The high price of this type of testing is due to various factors, such as the fixture size and board type.
An in-circuit test, also known as an ICT, is a type of testing that powers up and activates the individual components on a board. In most cases, it is designed to provide 100% coverage. However, in some cases, it can provide up to 85% coverage. This type of testing is completely free of human error.
This type of testing involves using fixed probes that are designed to match the design of the board. The bed of nails tester then pushes the board down to start the test. The ICT testing probes then connect to the circuit using access points that are pre-designed in the board. These points are designed to ensure that the connection stays intact.
AOI (Automatic optical inspection)
Using either a 2D or 3D camera, an automated inspection program known as Aoi takes detailed photos of your board. It then compares the images to a detailed diagram. If the board doesn’t match the diagram, it will be flagged for maual inspection.
Unfortunately, this program doesn’t automatically power up the board and can’t inspect all parts. It can be useful in identifying issues early, but it might not cover all parts. So this test would joint with other test method work together. Such as AOI and functional testing, AOI and in-circuit test (ICT), AOI and flying probe.
In addition to being used to test PCBs, burn-in testing is also a type of testing that involves exposing parts to load capacity. This method can cause severe damage to the parts being tested.
In burn-in testing, the power is pushed through the board at its maximum capacity, and failure rate lower the better. This method can be used in medical or military applications.
Although burn-in testing isn’t ideal for every project, it can be used in certain circumstances to prevent dangerous or embarrassing products from being introduced to the market.
One of the most important factors that you should consider when it comes to using burn-in testing, lifespan of the product might be shortened. And the test puts the board under excessive stress, it can cause it to break down.
X-ray testing can be used to check the hidden elements underneat a chip array package, such as connections between the ball grid and the chip package. However, this procedure can be very useful, but the operator must have the necessary experience and training.
Although an X-ray machine can sometimes detect internal defects in a board, This inspection may not involve every
layer of PCB board. This is a costly process, using this testing method, might increase your cost.
PCB manufacturer would use this testing method to check whether the board can work normal. This testing need some things: testing standard such as MSHA, UL, PSE, CE etc, Fixture, and some other facilities. This testing consume long time, if you need PCB board urgent, it may not suitable for your project. But in order to let you get a good quality PCB product, this testing is necessary.
Why you need printed circuit board assembly prototype?
The assembly of PCBs is a vital component of modern electronics. Even the slightest mistake in the manufacturing process can lead to fatal errors, which can result in the failure of the project to get underway. One of the most important factors that a PCB assembly company should consider when it comes to addressing its design issues is the use of prototyping. This process allows them to identify potential problems early on and prevent them from affecting the project. Make PCB assembly prototype you can enjoy benefits below:
Eliminate design error
While it is generally beneficial to handle the production of PCBs in-house, doing so can lead to some design errors that are not obvious to you. For instance, if you are planning on doing a quick turnaround on a project, you might end up with a manufacturer who doesn’t have the necessary expertise in one area. Having a third-party service provider help you identify these design errors can help minimize the risk of failure.
Make out better product
Even if your printed circuit board can be made to market quickly, it is very important that the final product is functional. Prototyping is the best way to ensure that your product is ready to be marketed. It allows you to iron out any potential issues and improve the quality of your finished product, which will help you gain an advantage over your competitors. Rapid testing and prototyping can also help you bring your better qualilty product to market faster, which will give you an edge over your competitors.
method of save time and cost
Although creating PCB prototype would consume your time and energy, it take the time still far less than your whole product design. If your product without prototype and with unfound defetitive to launch out into market, it may cause you a huge amount of time and money lose.
Besides in order to prevent you from extending your budget or getting stuck with additional projects and save time, we can adopt some actions like making more prototypes and test different stages to find out PCB problem quickly. That would prevent defective PCB going into mass production or market, cause your huge lose.
Test components part rapidly
Printed circuit boards are often complex and involve intricate designs. With the help of prototype design, you can test and verify the functions of PCB single component part and their single function, before they are integrated into the final product. That would let the work become simple, rapid and efficient, help you to save time and cost.
Difference between printed circuit board and printed circuit board assembly
There are two common types of electronic parts: a printed circuit board (PCB) and a printed circuit board Assembly (PCBA). A blank circuit board is a type of electronic device that does not have any electronic components attached. On the other hand, a PCBA is a finished assembly that contains all the necessary components to function properly.
Compared to the production of a completed PCBA, the process of manufacturing a blank board is more simple. However, it is also more expensive to produce a finished PCBA. PCB manufacturing is the initial step in the process, while printed circuit board assembly production further steps.
One of the biggest differences between the packaging of PCBs and PCBs is how they are handled. For instance, while PCBs are usually packaged in vacuum-based packaging, PCBs are usually packed in anti-static or compartmental packaging.
PApplication of printed circuit board assembly
Printed circuit board assembly (PCBA) are widely used in consume product, medical equipment, industrial control system, military devices, automobile etc, the follow equipment are all installed with PCBA.
- Satellite systems
- Storage equipment
- Telecom towers
- Industrial controls
- Machine Management systems
- Medical systems
- Lighting systems
- Home Appliances
- Cell phones
- washing machine
- vending machine
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