Basic Knowledge of In-Circuit Testing: What is the Difference Between Fixture-Based and Flying Probe Testing?

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There are two probing methods for in-circuit testing (electrical inspection of printed circuit boards): fixture-based and flying probe. **Fixture-based** A test fixture with embedded contact probes makes contact with the test board, allowing all probes to simultaneously touch designated test points on the board. In this state, inspections of each electronic component are performed while switching the measurement lines with relays. The boards to be inspected require a program that combines each inspection and the production of a dedicated fixture, which presents challenges in terms of cost, speed, and storage space. **Flying Probe** Multiple arms holding probes perform probing at any point on the board. While probe movement time is required, resulting in longer inspection times compared to the fixture-based method, it does not require a fixture and can be set up simply by changing the program. This leads to time and cost savings when viewed from an overall process perspective. It is also suitable for inspecting boards in low-volume, high-variety production. The coordinates of the test points can be arbitrarily changed, making it easy to accommodate partial design changes to the board. It is also used for prototype board inspections and failure analysis.

Measurement and Inspection