Inspection Procedures Used by Elite to Produce Quality PTH Circuit Boards
Inspection of phototools to ensure they are correct in terms of both scale (i.e. no stretching, shrinking, or distortion of design parameters) and completeness.
Inspection after drilling to ensure the correct base laminate has been used, no holes have been missed, all are the correct size, in the correct place, and are clean and clear (free of debris).
Inspection after electroless copper and panel plate to ensure the plating through the holes is clean and continuous (total copper coverage right through each hole).
Inspection after dry film laminating, exposure, and developing to ensure the circuit images are complete and free from residues.
Inspection after pattern plate and dry film stripping to ensure the circuits are free from residues.
Inspection after etching and etch resist stripping to ensure circuitry is free from shorts and opens, andtrack widths and copper thicknesses are correct.
Inspection after soldermask to ensure all pads are positioned correctly and clean.
Inspection after hot air solder level (HASL) or selective plating to ensure continued absence of shorts on circuitry.
Inspection after component location has been added to ensure it is complete and aligned correctly.
Inspection after routing or scoring to ensure board dimensions and any specified non-plated holes have been added and are correct.
Final check and pack having ensured the PCBs are cosmetically acceptable and the quantity ordered is the quantity despatched as scheduled to arrive by the promised delivery date.
N.B. All of the above also apply to the manufacture of quality multilayer circuits, of course, plus the inspections required when preparing and bonding layers, plus desmearing the drilled panels prior to through hole treatment for electrical conductivity.
