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What are ICT tests and what are their effects on pcb?

What are ICT tests and what are their effects on pcb?

At present, there are many types of testing technologies used in electronic product processing and testing. Commonly used are Manual Visual Inspection (MVI), In-Circuit Tester (ICT), and Automatic Optical Testing ( Automatic Optical Inspection (AOI), Automatic X-ray Inspection (AXI), Function Tester (FCT), etc.
The general side test can be classified into two categories according to whether the PCBA board is powered by power: one is electrical testing technology, the other is non-electrical testing, and the separation of PCBA can be divided into two major categories: one is contact. The end of the test, one is the non-contact test technology.
The online tester (ICT) is also called the flying probe (probe, needle bed) tester. Its principle is to check the electrical performance and electrical connection of the PCB components in the SMT chip processing to check the manufacturing technology for lack of money and components.

assembly process
The on-line tester uses a special flying probe to contact the components on the soldered PCBA board and conducts discrete isolation tests with a current of several hundred millivolts and a current of 10 milliamps to accurately measure the installed resistance and inductance. , capacitors, diodes, triodes, thyristors, window effect transistors, integrated blocks and other general and special components such as missing, mis-installed, parameter value deviation, solder joint welding, circuit board open circuit and other faults, and the fault is Which component or open-circuit is located at which point is accurately positioned.
The biggest advantage of the flying probe test is that the market responds quickly, but the detection speed is slow, suitable for test samples and small batch orders. If the customer asks for a sample, the flying needle test can be selected until the customer makes a large-volume order and then does the needle bed test. This eliminates the customer change process or cancels the needle bed production cost of the order.
The strength of ICT is electrical defect testing, such as the function of the device is not normal or wrong. Online testing can effectively find the various defects and failures that occur during the assembly process, but it does not fully evaluate the electrical performance of the PCBA.

assembly process
ICT requires the customer’s PCB design to meet ICT testability design requirements, and it is more cumbersome to implement for the diverse levels of PCBA processing customers. In addition, the more nodes the PCBA tests, the higher the cost will be, mainly in the design and manufacture of the needle bed or flying needle, and there are difficulties in testing. When the number of nodes exceeds the ICT requirement, the problem will be more difficult to resolve when the physical size of the PCBA exceeds the ICT requirements.
The miniaturization of electronic products has directly led to the miniaturization (high-density integration) of PCBA board design, and the value of PCBA design to ICT testing will disappear. This means that manufacturing will face a large number of potential problems. PCBA assembly will directly enter the final inspection, which will not only lead to a decline in the pass rate, but also increase the cost of repair and troubleshooting, and will also cause delays in production.

Mar-13-2019

FASTPCBA