All PCBs (Printed Circuit Boards), whether single-layer or multi-layer, should work flawlessly when designed and fabricated. This is crucial to make certain that PCBs are working according to their set criteria without any failure because, as in many electrical applications, lives may be on the line.
It is crucial to ensure PCBs’ performance, reliability, and functionality because there is always a chance of flaws and human error, even when following rigorous design and manufacturing procedures.
The PCB inspection services play an important role. While certain procedures are used in the early stages of PCB development, additional methods exist to test the PCBs as they are printed, mounted on a physical board, and prepared for final product assembly.
Advantages Of PCB Testing
Due to the benefits it offers, PCB testing is viewed as a “must-do process” by many businesses. Here, we have the following features:
Early Bug Detection: The primary advantage of PCB testing is the early detection of design, manufacturing, or functionality-related issues. PCB problems may result in difficulties with the finished product.
Fewer Returned Goods: Businesses that choose the “every module tested” strategy are less likely to sell damaged or substandard goods. On the other hand, it will improve brand recognition and client satisfaction. Additionally, it will save the money that would have been used to pick up the defective product from the customer’s doorstep or to send a service member to the customer’s location to repair the defective product.
Increased Safety: Because many PCBs are used in vital electrical devices, their failure can result in serious problems. For example, a faulty PCB could cause a fire, electric shocks, or any other accident.
An essential step in the PCB manufacturing process is PCB testing. Our first aim should be to lessen the likelihood that the final product will fail and to retain client happiness. Therefore, it is crucial to test the PCB using an appropriate and efficient method. One can object that there is no need to test the PCB card distinctly because it will eventually be tested along with the finished product. However, the testing phase that occurs throughout the manufacturing process will catch mistakes early rather than later when the deadline for the product’s delivery is approaching.
What PCB Testing Is Required:
A PCB could be simple or complicated and often consists of several components. Still, to prevent any regulatory violations, the following primary components and factors must be tested on every PCB:
Lamination on PCB: Testing the laminate’s resistance by laminating a PCB.
Copper Plating: To produce a strong copper connection from layer to layer, copper plating is done.
Component orientation and polarity.
Capacitors: Voltage is used to test the capacitor’s ability to perform properly.
Diode: It is used to stop current flowing in the wrong direction. It is a very delicate and small component.
Resistors: The resistors are tested using an ohmmeter.
In addition to the metrics described above, solderability, hole wall quality, and cleanliness are other critical considerations when inspecting the PCB.
Different PCB Testing Techniques:
After demonstrating how crucial it is to inspect the PCB, we will now go over each testing method in depth so that you may choose the one that best suits your project’s needs:
Manual Visual Inspection
This manual testing method calls for skilled individuals to carry it out. Here, the tester uses magnification glasses to examine the board. According to its components, they look for different kinds of problems. A common checklist can include items like excess soldering, dry soldering, installing components properly, and more. Since no special tools are needed, this is the easiest task to complete.
In-circuit Testing
This testing strategy uses a fixture, software, and an in-circuit tester. We may test for current flow, leakage, openings, resistance, shortage, and capacitance, among other things, using the aforementioned “testing combinations.” We may also examine the polarity and orientation of ICs and diodes. Individual components can also be tested in this scenario, regardless of whether they are connected to another component. Typically, we think of evaluating analog circuits in this way.
Flying Probe Examination
This form of test, often referred to as a fixtureless in-circuit test, uses a flying test probe that moves from one test point to a different test point in response to commands from the software program. It does not require a special fixture. These probes have cameras to examine the orientation and polarity of various components. As a result of its capacity to evaluate intricate and densely packed boards, this type of test has emerged as the standard for testing PCB.
Automatic Optical Inspection
It can be categorized as visual inspection techniques using a camera to take pictures of circuits from various angles and lighting situations. The “Expected Image” is then compared to these photographs. In testing terminology, this expected image is sometimes called a “Golden” image or board. This method’s drawback is that it occasionally can’t fully uncover hidden connections.
Test Of A Functional Circuit
As the name implies, the objective of this testing is the operation of the circuit. It might be regarded as the “last step” of any inspection procedure. In this test approach, the circuit is electrically energized before we observe the results, such as how LEDs, buzzers, and other indicators behave. Additionally, it can evaluate power absorption, current leakage (if any), voltage given to specific components, etc. Functional testing verifies that the PCB is fault-free and operating perfectly.
A PCB can have many problems; components may occasionally be out of alignment, and connections may sometimes be missing. On the other side, short circuits and bridge circuits can be brought on by dry soldering and excess soldering. Regardless of the PCB testing technique adopted, testing should be able to pick up 90–100% of abnormalities and other malfunctions, allowing us to pinpoint any potential flaws before the final product is produced.
