Ferrites India

On-line Magnet Testing & Sorting Machine

Functions and Special Features

The equipment is designed to test and sort alnico magnets in three groups 'GOOD', 'AVERAGE' and 'BAD'. The magnets with axially symmetric magnetization (cylindrical or rectangular) and magnets in 'C' shape, both, can be sorted. It has separate stations for mounting magnetizing and testing heads for these two types of magnets allowing permanent mounting of fixtures removing major source of error in sorting. The machine has stations available to introduce recoil testing of magnets if so desired in future. The machine offers sorted magnets ready for packing. It thus offers compatibility for further automation. There are separate stations for three qualities of sorted magnets. The machine can be easily adopted for any permissible different shape and size of magnet with minimum modifications because of its modular design of slots and mounting arrangements for the test fixtures.


The equipment has a ten-station turntable. The magnets loaded at Station I are carried to subsequent Stations. At Station III or IV the magnet is magnetized and the flux generated is measured. The limiting values for the sorting are set on the panel thumbwheels. The flux measured at Station III or IV is compared with limits set on the panel and quality of test piece is assessed. At Station VI the test piece is demagnetized and at Station VII, VIII & IX it is sorted as per the assessed quality at Station III or IV. Thus the magnets are available correctly sorted, totally demagnetized, ready for packing. Stations II and X are left to ensure removal of wrongly loaded or sorted test piece.

Operating Controls

The equipment has following control switches, buttons & settings:

  • START STOP control for the turntable
  • AUTO / MANUAL operation mode control
  • Two three digit thumbwheel settings for sorting limits
  • Separate switches to operate magnetizer and demagnetizer in MANUAL mode
  • Emergency STOP
  • RESET switch for software operation Selector Jumper Settings for selection of Station option (refer 'Operational Features ')

The equipment if furnished with following indications:
  • AUTO / MANUAL mode indicator lamp Alphanumeric display for the measured flux values of the test piece being sorted
  • Lamp indication for the group testpiece is being sorted to Indicating lamps for the status of magnetizer & demagnetizer operation
  • Waiting indicator
  • Additional features
  • Machine has following features already incorporated
  • Counters for magnets sorted
  • Speed of sorting: up to 20 pieces per minute
  • Size of magnets: a. Axially oriented: 15W X 15B X 25L mm or 15 ID X 30L mm max b. Horse shoe type: 20W X 30L X 20H mm max These sizes have to be confirmed with reference to your drawings while placing the order
  • Magnetizer and fixture at Station III & IV: Magnetizer is impulse type. Fixture is fitted with flux sensing sensor
  • Demagnetizer and fixture at Station VI: Demagnetizer is impulse type. The fixture is suitable for both types of magnets
  • Loading Station: Designed to push the test piece available on its platform in the turntable slot. Operates pneumatically. It is with facility for attaching a vibratory feeder for continuous supply of magnets under test
  • Flux sensing: Signal from flux sensor mounted in the fixture at Station II is processed and compared with set limits on the thumbwheels. ADC resolution 12 bit
  • Maximum reading counts 4000 Reproducibility of readings under same conditions = + - 2.7 % Comparator Set limit: three digits
  • Sorting: Done through operation of two pneumatically operated cylinder and push mechanism at station VII, VIII & IX
  • Indications on the panel: a. Lamps: AUTO/MANUAL mode of operation. Group of magnet being sorted. Status indication for the magnetizer & demagnetizer operation Wait indicator b. Digital Display: eight digits alphanumeric for measured flux values. Also gives other messages
  • Input Power: 230 +/- 15 volts three phase supply. Maximum loading 15 Amps
  • Air Supply required: at 6 bar pressure approximately 0.5 litres/min
  • System is fitted with all necessary safety interlocks and fuses.
The system offered here does not include vibratory feeder. Attachments on turntable slots are considered for only two sizes of alnico magnets.

Criteria for Inspection and Acceptance of On-line Magnet Testing & Sorting Machine

The equipment is designed to operate for the range of sizes and shapes of magnets mentioned in specifications given above. The present offer, however, includes necessary fixtures for only one size and shape of the magnet. All tests during inspection should be taken on the prior approved shape and size of the magnet. The reading and sorting accuracy and reproducibility of sorting for 15 nos. of samples should be seen over the operation of eight hours. The sorting done by the equipment should not be compared with the sorting done by any other method. In such cases where the sorting by other methods is showing different results our views should be considered as final. For the mechanical operation the equipment can be inspected for workmanship and safety but not for any design changes. The mechanical operation if desired can be seen discussed prior to execution of the order.

Hystersis Loop
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