Commercial Threshold
Contractual parameters and technical boundaries define a bare board procurement specification to govern the transfer of printed circuit boards from a merchant fabricator to an electronics manufacturer. Commercial terms establish liability for copper thickness violations, dielectric constant drift, and warp tolerances before any physical delivery occurs. Technical limits set the acceptable threshold for copper plating voids in through-holes, microsection grain structure, and solder mask adhesion strength.
Fabrication Metric
Dimensional accuracy demands precise control over etch factor allowances, laser direct imaging offsets, and drill wander parameters. Copper weight tolerances dictate how much base foil reduction is permitted during outer layer etching cycles. Laminate resin content controls dielectric spacing between inner layers to prevent impedance mismatch during high frequency signal propagation.
Dielectric thickness measurements verify that core materials and prepreg layers meet pressed height targets within specified percentage margins.
Acceptance Boundary
Visual inspection criteria regulate maximum allowable resin recession, weave exposure, and copper smear following mechanical routing operations. Electrical test parameters define isolation resistance floors and continuity resistance ceilings for net verification routines. Automated optical inspection equipment detects inner layer copper shorts and opens by comparing scanned panel data against reference Gerber files.
Final shipment release depends entirely upon passing thermal stress float testing without delamination or barrel cracking.
