Suction Mechanism
Pressure-differential clamping system holds a circuit board securely against a test interface using atmospheric force. A vacuum fixture creates a seal around the perimeter of the board and removes the air from the cavity beneath it. This pressure difference pulls the board down onto test probes with a uniform force.
Such systems are common in high-volume production environments where fast cycle times are necessary.
Seal Integrity
Vacuum maintenance depends on the quality of the gasket material and the flatness of the board surface. If a vacuum fixture has a leak, the downward force will be insufficient to compress the test probes, leading to intermittent contact. Operators must inspect the seals for wear and debris that could prevent a tight fit.
High-flow vacuum pumps are used to compensate for small leaks caused by through holes or unpopulated vias in the circuit board.
Testing Throughput
Production efficiency is improved by the rapid engagement and release of the board from the fixture. When a vacuum fixture is used, the time required to secure the board is reduced to a few seconds. This allows for higher testing rates compared to mechanical clamping systems.
Automated handlers often use these fixtures to move boards through the functional test stage without human intervention.
