A Metal detector is used to find out and remove small pieces of ferrous, non-ferrous, and SS during tablets compression in pharmaceuticals. Such types of metal entered into the product during the batch process, such as worm sieve wires. The metal detector comes into the role at this time where it removes such types of contaminants. However, the Metal Detector Challenge Test is done to check the sensitivity of the metal detector. It automatically detects and removes the contaminants without harm to the tablets and capsules during the manufacturing process. The pneumatic solenoids activate the reject flap and remove the contaminants.
Principle of metal detector
An electromagnetic Induction Metal detector contains one or more inductor coils used to interact with metallic elements on the ground. A pulsing current is applied to the coil to which induces a magnetic field. When a magnetic field of coil moves across metal, the field induces electric current (eddy current)in metal.
Eddy current induces their magnetic field, which generates an opposite current in the coil, which induces a signal indicating the presence of metal. The metal detector consists of an oscillator that produces an alternating current. It also contains a receiver coil.
The modem of metal detector based on:
- VLF-Very low-frequency
- PI-Pulse Induction
- BFO-Beat Frequency oscillation
- VDI-Visual discrimination indicator
- Sensitivity of Metal detector:100 Food grade plastic flap Sensitivity, timer, and phase setting
Metal detector challenge test kit
- Fe (Ferrous)- 0.15 mm
- NFe (Non-Ferrous)- 0.25mm
- SS( Stainless steel AISI 316)- 0.25mm non-magnetic
- Dummy: Without metal particle and has no diameter
Challenge test Procedure for Metal Detector:
Switch on power supply, now passes the dummy sample. It should be a pass.
Then pass SS, Fe, and Non-ferrous one by one. It should be rejected.
Note: if the metal detector test failed, immediately stop the machine and inform to head of the department and QA and raise a request or breakdown. Put a breakdown label on the metal detector.
Frequency of challenge test:
- At the start of batch and then every two hours alternatively by production and QA.
- End of a batch by Production and QA.
- After the breakdown.
Metal detector challenge test for Capsule:
Metal Use to do challenge test for the Capsule is:
- Fe (Ferrous)- 0.60 mm
- NFe (Non-Ferrous)- 0.80mm
- SS( Stainless steel AISI 316)- 1.00mm non-magnetic
- Dummy: Without metal particle and has no diameter
