The Power of Flying Probe Test in PCB Testing

The technology underlying the Flying Probe Test (FPT) and its contribution to improving PCB testing are examined in this article. It goes into FPT’s background, workings, and advantages over conventional testing techniques. The article also explores FPT’s many uses, including its use in numerous industries and the various PCB types it can test. The paper also emphasizes the value of FPT in assuring PCB quality and dependability and lowering the possibility of product failures. The future of FPT and its potential to keep changing the PCB testing scene is discussed as it comes to a close.


A key element in the production of electronics is the PCB or printed circuit board. It is a flat board with conductive tracks and pads on one or both sides that allow for the exact positioning and connection of components. The substrate is non-conductive (mainly fiberglass). Almost all electronic devices and applications require PCBs, and the total performance of the finished product depends greatly on their quality and reliability. Various testing methods, from hand inspection to automated testing procedures, are utilized to assure the quality of PCBs.

The Flying Probe Test is one of the most efficient automated testing methods used in PCB manufacture. Robotic probes are used in this non-intrusive electrical testing technique to check PCBs for flaws and make sure they adhere to the necessary standards and requirements. In this article we will cover in-depth knowledge about the Flying probe test, how FPT works, and why and where is it used in industry.

What is Flying Probe Test?

Flying Probe Test (FPT) is a type of automated test equipment used for testing printed circuit boards (PCBs) for faults or defects. It works by using a set of probes that fly over the surface of the PCB, making electrical contact with the circuit nodes, and performing tests to check for functionality and potential issues. The FPT technology was first developed in the 1980s by Digital Test, a company based in the United States. The first FPT machine was launched in 1989, initially, it was used to test bare boards by testing electrical resistance between connected paths. The technology quickly gained popularity due to its speed, accuracy, and flexibility and became an industry standard for the quality assurance of bare PCBs. Technological advances in recent years have expanded the use of FPT for testing PCBs populated with passive components.

Figure 1 Flying Probe Test : Testing of populated PCB
Figure 1 Flying Probe Test: Testing of populated PCB

FPT has become a crucial technique for testing PCBs in several industries, including automotive, aerospace, medical devices, telecommunications, and consumer electronics. Its use has increased globally. From small single-sided boards to big multi-layer boards with complicated geometries, FPT machines are made to test a variety of PCB sizes and complexity.

How the Flying probe test works

Flying Probe Test (FPT) is a non-invasive technique employed in the electronics sector to examine printed circuit boards (PCBs) and ensure they adhere to the appropriate industrial standards. This test procedure is commonly used in the production of Surface Mount Technology (SMT) PCBs and is crucial for quality assurance. PCBs can be precisely and effectively tested during the test procedure with the aid of specialized test equipment (Figure 2). The FPT apparatus comprises a collection of probes fitted on a moveable head. Passive testing and component placement verification are only a couple of the tests that may be carried out with these probes in contact with the PCB.

The FPT test process consists of several steps, the machine employs an x-y grid that it extracts from ASCII or ODB machine files for basic CAD. The circuit board’s coordinates are programmed into the computer. The inclination of the needles’ descent is 45 degrees. The prober has to connect to two access points on the board. The value is determined and set by the machine programmer. The machine then validates that value for various points on the PCB, checking for continuity, resistance, and capacitance, among other parameters. Due to the flexible nature of FPT, it has become an Industrial standard for most low-volume applications.

Figure 2 Flying Probe Test Station EMERIX Technologies
Figure 2 Flying Probe Test Station EMERIX Technologies

Application of FPT in Industry

FPT technology is commonly used in the PCB production process to perform various tests, including continuity, isolation, capacitance, and resistance. Unlike Bed-of-nails testing, FPT does not require the use of test fixtures, making it a faster and more efficient option. FPT can also test complex circuit boards with fine-pitch components and non-functional pads.

Where to use FPT?

FPT is especially helpful for high-mix, low-volume production, prototype testing, and small-batch manufacturing. It can immediately spot flaws and errors, enabling producers to make the necessary adjustments before beginning mass production.

 The capacity of FPT to increase manufacturing efficiency is one of its main advantages. FPT is quick to set up and simple to automate, which lessens the need for manual labor and test setups. In consequence, this can drastically lower testing costs and accelerate manufacturing as a whole.

FPT can enhance product quality by spotting flaws early in the manufacturing process. Early fault detection allows producers to fix problems before they get more serious and cost-prohibitive product recalls or customer returns occur. FPT can also ensure that products meet industry standards including IPC 9252A which is an industry standard to check electrical conductivity on printed circuit boards. By making sure these rules are followed, producers may avoid fines, ruin their reputations, and produce high-quality goods that meet ISO 9001 requirements.

FPT is a valuable technology for PCB testing that offers many benefits over traditional testing methods such as Bed-of-nails testing. Its ability to improve production efficiency and product quality makes it a preferred testing option for many manufacturers. As the demand for PCB testing automation continues to grow, FPT is likely to become even more essential in the production process.

Figure 3 Bare-board testing for PCBs using Flying Probes
Figure 3 Bare-board testing for PCBs using Flying Probes

Comparison with other Test methods

When it comes to PCB testing, there are several methods available, each with its own set of benefits and drawbacks. Two of the most commonly used methods are Flying Probe Test (FPT) and In-Circuit Testing (ICT). In this article, we will compare the FPT and ICT methods and discuss their benefits and drawbacks.


FPT and ICT are both used to test the electrical connections and components on PCBs. However, they use different testing methods to achieve this goal. FPT uses a set of probes that move over the PCB, making contact with various points to test for continuity, shorts, and other faults. In contrast, ICT uses a bed-of-nails fixture to contact multiple points simultaneously, allowing for more comprehensive testing of the board’s functionality.

Benefits and Drawbacks of FPT:

Flying Probe Test (FPT) is a popular and versatile technique used in PCB testing assembly to identify and locate electrical faults in printed circuit boards (PCBs). It offers numerous benefits over traditional Bed-of-nails testing, making it a preferred testing option for many manufacturers.

One of the main benefits of FPT is its flexibility. It does not require test fixtures, allowing it to test PCBs with non-functional pads or fine-pitch components. FPT is also faster and more efficient than ICT, making it a better option for small-batch production and prototype testing. However, FPT may not be as comprehensive as ICT since it tests each point individually and may miss some faults that only become apparent when multiple points are tested simultaneously. FPT may also be more expensive than ICT for high-volume production due to the time required to test each board.

Benefits and Drawbacks of ICT:

ICT is a more comprehensive testing method than FPT since it can test multiple points simultaneously. This makes it better for high-volume production where speed and efficiency are critical. However, ICT requires a test fixture to make contact with the PCB, making it less flexible than FPT. ICT fixtures are also expensive and time consuming to design, making ICT a more costly option than FPT for small-batch production and prototype testing.

Cost of PCB Testing:

The cost of PCB testing depends on several factors, including the complexity of the board, the type of testing method used, and the volume of production. FPT is generally more expensive than ICT for high-volume production since it requires more time to test each board. However, for small batch production and prototype testing, FPT may be a more cost-effective option since it does not require the use of test fixtures.

In conclusion, both FPT and ICT have their own set of benefits and drawbacks. FPT is more flexible and efficient than ICT, making it a better option for small-batch production and prototype testing. However, ICT is more comprehensive and efficient than FPT, making it a better option for high-volume production. Ultimately, the choice between FPT and ICT will depend on the specific requirements of each production process, including the complexity of the PCB, the required testing coverage, and the volume of production.

Limitations of FPT

Flying Probe Test (FPT) is a popular method of testing Printed Circuit Boards (PCBs) in the electronics industry. However, like all test methods, FPT also has its challenges and limitations. In this section, we will discuss the challenges and limitations of FPT and how new advances are being used to overcome these challenges.

One of the primary challenges of FPT is testing speed. FPT has a relatively slow test speed compared to other test methods, such as In-Circuit Test (ICT) or Automated Optical Inspection (AOI). This is because FPT uses probes to make contact with the PCB, and the probes must move to each test point individually. Another challenge of FPT is the complexity of the PCB being tested. As PCBs become more complex, it becomes more difficult to access all the test points, which can lead to incomplete testing. Additionally, the high component density of Surface Mount Technology (SMT) PCBs can make it challenging to accurately place probes on the PCB.

FPT is also limited in its ability to detect certain fault types, such as intermittent faults or faults that occur under specific conditions. This is because FPT tests each point on the PCB individually, and intermittent faults may not occur during the testing process.

Advances in FPT Technology

While FPT has its challenges and limitations, new advances in FPT technology are being used to overcome these limitations. New Flying Probe Test Stations are equipped with multiple sets of probes that can reduce the overall testing time. Additionally, some vendors provide the option for attaching magnetic test pins on the bottom plate of the tester so that both the top and bottom sides of the PCB can be tested at the same time. The addition of these features reduces the overall testing duration per PCB using modern FPT stations. Another top feature is the inclusion of multiple test types in addition to FPT to increase the overall reliability of the quality procedure. FPT stations now come equipped with other forms of tests like the Automated Optical Inspection (AOI) test, using more than one test further ensures the quality of the products.

In conclusion, Flying Probe Test (FPT) is a widely-used method of testing Printed Circuit Boards (PCBs) in the electronics industry and new advances in FPT technology ensure increased accuracy, precision, more comprehensive test programs, and flexible test fixtures and assembly-making FPT a viable tool for industries across the globe.

Which is better FPT or ICT?

FPT is vital for ensuring that PCBs meet the required specifications and perform as intended. The flexible nature of this test makes it useful for areas where there’s a wide variety of different products.

Whereas ICT provides a more comprehensive test including a functional test of populated PCBs, it is faster and a more reliable test as compared to FPT.

Both tests have their field of use. Low-volume builds benefit significantly from the flying probe. Low volume is generally defined as a couple of hundred boards per year or something in that range. ICT, meantime, requires a significant amount of PCBs to be profitable.


In the electronics industry, quality is of utmost importance, and FPT is a critical tool for achieving that quality. By utilizing the latest FPT technology, manufacturers can ensure that their products meet the required specifications and perform reliably, reducing the risk of product recalls and improving customer satisfaction. In conclusion, FPT is an essential part of the electronics industry, and its evolution will continue to drive innovation and excellence in PCB testing.

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