Calibration Procedure of Metal Detection Machine (9 Points Calibration) | ©AllaboutQMS

Calibration of Metal Detection Machine

Conveyor detectors should be calibrated to 1.0-1.2 mm/customer’s standard ferrous object detection.

The 9 Point calibration ensures that the equipment is functioning correctly and operating at the correct sensitivity (1.0, 1.2mm or as per customer’s standard).

• The 9 Point calibration must be done a minimum of 2 times per shift or every time when the machine is out of power/switched off by a certified and trained operator. It is recommended to do it every hour.

• Proper documentation of calibration should be maintained.

Tools Required For Calibration

Metal/ needle detector test card and stand

The procedure of Metal Detection Calibration

1. The 9 Point Calibration check on the detector is done by dividing the metal detector conveyor belt into 3 zones.

2. The Calibration Card, supplied by machine vendor, should be passed through each of these zones at three different height levels.

                Left Center Right
Top           A7      A8      A9
Center      A4     A5       A6
Bottom      A1     A2      A3

3. The Detector sensitivity must be set at a level which is less than the customer’s requirement (1,1.2mm etc.).

4. The Calibration Card should be placed on the conveyor belt and passed through each zone and A, B and C readings to be recorded on a 9 Point Calibration Report.

Recording Results

The 9 Point Calibration Report should be marked as follows

Y /ok/✓- if the needle detection activates (alarm sounds, the light activates and the machine stop or reverses the card ) when the Ferrous Calibration Card is passed through the search head.

N/Not ok/X – if the needle detector has no reaction (no alarm sound/light/reverse movement of belt) when the Ferrous Calibration Card is passed through the search head.

• If there is no reaction during the 9 point Calibration procedure and report is fail (even a single reading/result fails) the operator must stop the machine and call the supervisor. The product should not be tested with such a machine.