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.
Component Level Rework
Thermal Extraction
Component level rework is a corrective manufacturing procedure used in printed circuit board assembly to remove and replace defective or out of tolerance surface mount packages without damaging neighboring circuitry or the base laminate. Advanced infrared and forced convection systems apply localized heat profiles to melt solder joints beneath the targeted device while a vacuum pickup tool extracts the faulty part from the pads. Technicians must clean residual solder from the exposed site using desoldering braid and flux before applying fresh paste or preforms for the replacement package.
Metallurgical Recovery
Reattachment relies on precise thermal control to form acceptable intermetallic compound layers between the component termination and the substrate pad without inducing copper delamination or thermal shock within the internal layers of the multilayer board. Excessive dwell time at reflow temperatures causes solder joint embrittlement and pad lifting, whereas insufficient heat prevents complete wetting and creates cold joints that fail during subsequent vibration screening. Inspection following the replacement cycle involves X-ray imaging to verify void percentages beneath grid array packages and optical inspection to confirm proper fillet formation on peripheral leads.
Yield Verification
Functional testing and electrical bench verification determine whether the repaired circuit assembly meets the original performance criteria established for the production run. Reworked modules undergo automated optical inspection and boundary scan testing to detect bridging or open circuits resulting from misaligned placement during the second reflow operation. Quality assurance protocols dictate that repeated corrective cycles on a single location are prohibited due to cumulative thermal stress degradation on the copper traces and laminate resin systems.