The 6 Most Common PCB Quality Assurance Tests

The 6 Most Common PCB Quality Assurance Tests

PCB Quality Assurance, PCB Testing Methods, PCBs Manufacturing Services, pcb quality assurance

Printed circuit boards (PCBs) are used in nearly every electronic product manufactured today. In order to fit integrated circuits and other critical connections with smaller dimensions, designers continue to push the limits of PCBs.

Consequently, PCB assembly manufacturers must perform thorough quality assurance testing to satisfy increasing connectivity demands and rapid electronic manufacturing advancements. To detect defects in almost microscopic packages, manufacturers conduct tests such as in-circuit testing and X-ray inspections.

When a product’s characteristics definition is flawed, such as the power consumption or size, the result is both an impact on the individual board and a significant risk to both manufacturing and supply chains. The ultimate goal of a manufacturer is to achieve higher production yields at lower costs and with fewer defects. A defect can, therefore, undermine this goal.

In this article, we discuss various quality control testing methods used during the electronics manufacturing process.

PCB Quality Assurance Tests

1. In Circuit Testing (ICT)

The most common method of testing PCBs is the in-circuit test (ICT). This capacitance test involves inspecting both open and short circuits along with component values and IC operation.

To measure resistance, small spring-loaded pogo pins are pressed into various areas of the nail bed. By pressing the probes into the nail bed, the board’s solder connections are checked.

The board is pushed down on the bed of nails (bed of probes) to start the test. The design process will create pre-constructed access points on the board that allow the circuit testers to gain access to the circuit.

It is common for manufacturers to perform ICT on products with few revisions expected. If your board does not have the appropriate pads built with a design-for-manufacturing testing goal, ICT is not possible. It is not possible to switch to ICT halfway through production.

Failure is a costly event when you order PCBs. Manufacturing companies include PCB assembly testing methods as an integral part of their production process. In the following section, we will discuss six basic PCB testing methods.

PCB Quality Assurance Tests

2. The automated optical inspection (AOI)

An Automatic Optical Inspection is widely used in manufacturing environments because it provides faster and more accurate results than manual methods.

Using either 3D or 2D cameras, AOI takes photos of the PCB before comparing them to a detailed schematic. Technicians flag boards for inspection which do not match the schematic to a certain degree.

AOI should never be relied upon solely. PCBs cannot be powered up, and their coverage does not encompass all board components. Ideally, you should pair the functional test with a flying probe, in-circuit test, or in-circuit test.

AOI is particularly useful when placed at the end of the soldered-board manufacturing process. Here, it can help identify problems like loose solders in the production line. AOI testing can capture and resolve developing issues quickly before they impact subsequently manufactured PCBs.

PCB Quality Assurance Tests

3. The flying probe test

With this non-powered test, we check for open circuits, short circuits, capacitance, resistance, inductance, and diode problems. The test is performed with needles attached to a basic CAD grid probe. Once you have matched the circuit board and checked for errors, the test is complete.

In-circuit testing is more expensive than a flying probe, because it has to be designed to fit with the test fixture. The ICT test, however, is faster and less prone to error. Comparatively to the flying probe, ICT can also be more cost-effective for orders with higher volumes.

4. X-Ray Inspection (AXI)

For most electronics manufacturers, AXI is a valuable inspection tool. By inspecting the solder connections, barrels, and internal traces of the component, an X-ray technician can identify defects during the manufacturing process. X-rays come in both 2D and 3D formats.

With an X-ray test, hidden elements can be checked, for example, ball grid array packages with their solder joints underneath the chip package. An experienced operator is required to operate the X-ray test. In addition, it is costly and time-consuming.

Do you have questions regarding which material will best suit your needs? Contact us today, our professional staff is ready to help!

5. Functional Test

A functional test is used by manufacturers to make sure a product works properly. Test equipment and fixtures are necessary to perform it. Standard specifications (such as UL and MSHA) must also be followed.

Most manufacturers can assist customers in designing and developing functional tests by providing functional test plans and their parameters. Although functional testing takes time, it is worth the effort from a quality and longevity standpoint.

Your design team is able to identify components that need modification early by using PCB prototyping. It would be a time-consuming process to identify the causes of inadequate performance and other flaws without it, which could substantially extend the completion of your project.

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PCB Functional Testing

6. The burn-in test

Burn-in is an intensive PCB test for detecting failures in advance and determining load capacity. The intense nature of burn-in testing may result in the destruction of other components. This device continuously pushes power through your PCB for 48 to 168 hours, usually at its maximum capacity.

The term “infant mortality” is used by manufacturers to describe a board failure. Medical and military applications require this type of test, since boards with a high infant mortality rate are not ideal. Not all projects should undergo this test as it can reduce a product’s lifespan.


To make sure defective boards do not make it to assembly in mass production, PCBs must be tested during the manufacturing process. It is important to not overlook PCB prototyping, since it also acts as a test, allowing you to see your real product before your market does.

Omnidex Electrical and Electronics Manufacturing Services

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As a British-owned manufacturing facility in China and Vietnam, offering end-to-end solutions to our OEM customers in the areas of automotive, medical & healthcare, marine, aerospace electronics and more.

Whether you are an emerging start-up company or a blue-chip corporation, we are keen on providing the most adequate solution for your next project. Contact Us to discuss more details or learn more about our other manufacturing processes and services.

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