When configuring metal detection, first define the detection points. Common practice is to place inspection at raw material intake, after critical processing steps and before finished-product packaging, with pre-packaging inspection particularly important because product form is stable and the reject zone is easier to define. For long lines or multiple product types, detection can be set by risk level at one or several points, matching conveyor speed and product flow to avoid accumulation or posture changes affecting results.
Equipment selection should match product characteristics. Foods with high moisture, salt content or aluminum foil packaging place different demands on phase and frequency settings, so buyers should provide actual product samples for testing. Needle detectors suit textiles and light industrial goods, while food lines typically use metal detectors or X-ray inspection; X-ray can identify metal, glass and bone but requires evaluation of product density and packaging. Reject devices, alarm modes and data logging also matter.
Installation, commissioning and routine verification determine actual performance. Equipment should avoid vibration sources and high-power motors, and conveyor belt joints and rollers should be checked regularly. Use standard test pieces at fixed intervals to verify sensitivity, record results and integrate them into the quality management system; reconfirm parameters after product changes. Test reject devices regularly to ensure nonconforming products are separated, and keep inspection and verification records for traceability and audits.