Buying a Metal Detector: Installation, Calibration, and What to Confirm Before You Order

Once configuration (gravity-fall or inline conveyor), sensitivity, and IP rating are settled, the remaining decision is which supplier installs it correctly and keeps its detection performance verified over time. For contamination-detection equipment specifically, ongoing calibration matters as much as the initial spec — here's what to confirm.

Installation and Commissioning

For gravity-fall detectors, installation covers aperture alignment into the material fall path and integration with the reject mechanism below it. For inline conveyor detectors, it covers belt speed matching, opening clearance around your actual package dimensions, and reject system timing (pneumatic pusher, air-blast, or divert conveyor, matched to your line speed and product weight).

Commissioning should verify detection sensitivity against certified test pieces for your product — ferrous, non-ferrous, and stainless steel — at your actual production speed, not a static bench test. If your line runs mixed SKUs, commissioning should also confirm product memory settings are correctly stored and load automatically per SKU, since this is exactly the detail that prevents the kind of sensitivity drift that causes a failed contamination audit.

Calibration Is Not a One-Time Event

A metal detector's detection sensitivity can drift with vibration, electrical interference, and component aging — which is why ongoing calibration matters more here than on most other equipment types. Before you order, confirm:

• Calibration frequency recommended for your application — annual is a minimum for most food and industrial applications; quarterly or monthly may be appropriate for regulatory-critical or export-facing lines.
• What documentation you receive — a proper calibration should produce a written certificate showing equipment identification, reference test pieces used, before/after readings, pass/fail determination, and next due date. Without this documentation, you have no audit trail if a customer or regulator asks for one.
• Whether third-party equipment is covered — if you already own a metal detector from another supplier, confirm whether your new supplier can calibrate it too, since consolidating calibration under one provider simplifies your maintenance schedule.

ENZAC provides calibration services for metal detectors, checkweighers, and magnetic separators — both equipment it supplies and third-party equipment of the same type — with a written calibration certificate and is working toward SIRIM accreditation, with procedures aligned to ISO 17025 principles.

After-Sales Support to Confirm Before You Sign

• Spare parts — sensor coils, reject mechanism components, and control electronics are the parts most likely to need eventual replacement. Confirm stock availability and lead time.
• Service and maintenance — scheduled inspection catches reject mechanism wear and sensitivity drift before they become a compliance issue. Confirm response time for a breakdown callout, since a failed metal detector often means a line stoppage until it's resolved or bypassed.

Warranty Terms

Confirm coverage (detection head, control electronics, reject mechanism) versus exclusions, the warranty period, and whether it starts at commissioning sign-off or shipment. Also confirm whether initial calibration and certification are included in the purchase price or billed separately — this is a detail worth clarifying before, not after, the quote is accepted.

Sizing the Decision to Your Actual Audit Risk

If your business has already faced or is trying to avoid a failed metal contamination audit, the conversation with your supplier should go beyond sensitivity specs to include product memory management, documented calibration cadence, and — where sub-threshold contamination is a real risk — a grate magnet separator paired upstream to catch what the detector's own sensitivity floor can't.

Review the full Metal Detector equipment page for configuration and specification detail.