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.
Board Strain Flexure
Mechanical Deformation
Circuit assemblies endure physical displacement during manufacturing stages like depaneling, connector insertion or final housing installation. Board strain flexure quantifies the degree of physical curvature a printed circuit board undergoes when subjected to these external forces. Excessive bending creates tensile or compressive stresses that propagate through the substrate to sensitive component interfaces.
Solder joints crack under this persistent loading because intermetallic layers possess limited elasticity. Precise characterization of this behavior prevents latent failures in hardware field operations.
Test Methodology
Measurement begins with the application of strain gauges placed near components prone to failure under load. These sensors capture the change in resistance caused by substrate elongation and convert those values into microstrain units. Technicians perform the verification during the physical handling steps that present the highest risk of board distortion.
Data acquisition systems record the peak deformation values to confirm they remain below established safety thresholds. Consistent monitoring ensures that manufacturing processes maintain alignment with structural integrity requirements.
Risk Threshold
Assembly guidelines dictate specific limits for deformation to ensure long-term product reliability. Engineers define these limits based on the solder alloy composition and the package size of mounted integrated circuits. Ceramic capacitors frequently sustain damage when the local board curvature exceeds a set value for a given distance from the solder joint.
Tight adherence to these boundaries eliminates mechanical fatigue before units exit the factory floor. Proper process design minimizes the frequency of induced board strain flexure.