Calculating Landed Cost Crossover between Flying Probe and Fixture Tooling
Landed cost crossover balances fixture NRE against probe runtime fees, shifting financial advantage to fixtures once batch volume savings offset tooling costs.
Flying Vector Test
Diagnostic Routine
Automated inspection routine is a software-driven inspection procedure used with robotic probe systems to verify the functionality of digital components without a fixed fixture. Applying flying vector test sequences allows moving probes to execute specific input patterns to stimulate logic gates and observe the resulting outputs. Automated routines provide fault coverage for complex integrated circuits on low-volume assemblies.
Signal Sequence
Engineers develop test patterns that exercise the internal logic of a device by toggling specific pins in a defined order. The flying vector test requires precise timing to ensure that the robotic probes maintain contact during the entire pulse sequence. Because the probes must travel between different component pins, the cycle time for this method is longer than that of a dedicated bed-of-nails fixture.
Digital models of the components enable the software to predict expected responses for comparison. Probes move with high acceleration to minimize the transition time between disparate test points on the circuit board surface.
Implementation Constraint
High-speed signals often face degradation due to the long wire leads and parasitic capacitance inherent in moving probe systems. Consequently, the flying vector test is usually performed at lower clock speeds than the actual operating frequency of the circuit. This limitation makes the technique best suited for checking connectivity and basic logic rather than full-speed timing verification.