PROCESS   
 
Hard Ferrite/Ceramic magnets can be produced with either isotropic or anisotropic properties. Anisotropic properties are derived from the high magneto-crystalline shape anisotropy of the ferrite particles. Physical orientation of the ferrite particles is necessary in the pressing process to achieve magnetic alignment.

Hard Ferrite magnets have excellent corrosion resistance and have normal operating capabilities between -40°C and +250°C. As temperature increases, remanence decreases by 0.2%/°C whereas coercively increases by 0.3%/°C. At very low temperatures there is a risk of permanent demagnetization in magnet systems with low working points.

The excellent and consistent magnetic and physical characteristics of GPEL`s ferrite magnet are established by integrated manufacturing process, which is evolved through long experience ,unique technology and know-how acquired from a world leader like TDK Corporation ,Japan.

Innovative manufacturing technology continuous involvement of process control and new TQM initiatives enable GPEL maintain high level of quality at the most competitive prices in the world.

The following shows the manufacturing sequence from raw material input through to the final inspection.
 

RAW MATERIAL
Purity of raw material is largely responsible for the magnetic properties of the products. Different grades of raw materials are procured either from local source or from sources abroad to produce magnets as per customer requirements.

MIXING
The Wet mixing process adopted by GPEL ensures homogeneity which is very essential for the next process i.e. calcining process.

CALCINATIONCALCINATION
This is the pre-firing process which produces the basic magnetic characteristic in the raw materials. Calcination is done in a Rotory Kiln where the temperature is controlled in a very narrow band.





MILLING
The coarsed milled powder which is obtained from Vibro Mills are into Attritors for fine milling. Necessary additives to enhance magnetic properties are added at this stage.

KNEADINGWATER REMOVAL AND KNEADING
The thin slurry from Attritors is passed through filter press and is well kneaded to form homogenous slurry for wet press moulding.

MOULDINGMOULDING
Thick slurry after dewatering and kneading is pumped into the die cavity by a high pressure filling device. During the process of compaction a magnetic field is applied to align the particles in the desired direction. The water that comes out during the process of compaction is removed by vacuum. The green product thus formed inside the die cavity is de-magnetised before removal from die cavity. 



SINTERINGSINTERING
The green magnets from the moulding press are passed through a dryer and the sintering furnace which is basically a Roller Hearth Kiln with stringent temperature control facilities.






GRINDING, CLEANING AND PACKING
The sintered magnets are ground in double disc grinders, incase of loud speaker ring and in multi spindle segment grinders incase of arc segments. Thereafter they are cleaned in ultrasonic bath, dried and packed.

INSPECTION AND SHIPPING
Our well trained Q.A. inspectors monitor the process through- out and also carry out a release inspection prior to dispatch of finished goods to the customers.