Different kinds of metal detector Inspection:
Metal detector
Security detectors
Fold walk through metal detector
Hand-held metal detector
Underground metal detectors.
Metal detector door
Transport metal detector

Some common factors for metal detector quality control:
Appearance check
Quantity check
Measurement of product
Packing check
Function test
sensitivity level check
Battery voltage check
Internal check
Product endurance test
Pull test for cord
Charging test
Hi-Pot Test