What is ICT (In-Circuit Test)?
The In-Circuit Test (ICT) is a testing methodology used to verify the correct functioning of a printed circuit board (PCB) by checking its electronic components without the need to power up the board.
Why is ICT testing crucial?
In the world of electronic assembly, the ICT (In-Circuit Test) is an indispensable tool for ensuring quality and reliability. This test detects electrical faults that traditional functional testing might miss because:
- It identifies shorts and open circuits, which are otherwise difficult to detect.
- It ensures correct component assembly, reducing the risk of future failures, especially as electronic components are every day smaller in their sizes, making optical code reading increasingly difficult.
- It helps detect issues, especially in medium/low volume production, that may arise after the SMD mounting stage, possibly due to materials not ideally packaged for being automatic assembled.
This low investment cost in terms of Labour costs, can prevent unforeseen issues during the final use phase, avoiding unpredictable economic consequences.
Through specific machine programs tailored on each PCB code, the ICT checks the board according to the coverage rate specified or requested by the customer. At Nortech Elettronica, we have technical tools for DFT (Design for Testability) analysis, allowing us to assess during the design, what the resulting test coverage will be. These preventive analyses enable us to implement necessary actions during the design process to meet the customer’s expected test coverage goals.
As above said, the test coverage percentage is largely determined by the design characteristics of the circuit itself, and the actions performed during the test include:
- Component Testing:
Measurement of resistors, capacitors, inductances, diodes, and transistors directly on the board.
Checking connections between components to identify short circuits or open circuits.
- Partial Functional Testing:
The ICT does not fully verify the circuit’s operation as a complete Functional Test (FCT) would. However, it can conduct partial tests to confirm that signals are being transmitted correctly.
- Detection of Common Defects:
Missing or incorrectly mounted components.
Defective components.
Soldering issues, such as cold joints or solder bridges.
These inspections are carried out using dedicated machines, which, through a series of probes that make direct contact with the pads or test points on the boards, measure the electrical response to verify that it matches expectations and that there are no soldering or assembly errors.
At Nortech Elettronica, we can perform ICT test having Flying and Bed-of-Nails testing machines using SPEA systems, enabling us to meet the needs of both medium/low volumes and significantly higher volumes.
