Manufacturing of Amorphous Metals

Manufacturing of Amorphous Metals

  • Molten Metal Feed through small nozzle slot onto rapidly moving, water cooled substrate.
  • Rapid Solidification - 106 Deg Centigrade.
  • Approx 100 kmph speed of the line.
  • Continuous operation with multi hub indexing winder.
  • Careful raw materials and melt chemistry control.
  • In line sensing and control.
  • No Load Losses constitutes of 2 parts
    • Hysterisis Loss – 1/3rd
    • Eddy Current Loss – 2/3rd

Amorphous gains high magnetic properties since it is quenched (rapid solidification) from a very high temperature and thus the hysterisis losses are drastically reduced.

The laminations comprise of Thin Ribbons and the thickness of the sheet is about 1/10th that of the CRGO grade (i.e) 0.023 mm. Eddy current losses are proportional to the square of the thickness of Laminations and in this case these losses are also reduced. Thus Amorphous is a better technical product than any existing Transformer Core Grade.

Core Making in Amorphous Core Transformer

Amorphous Ribbons comprise of Thin Ribbons and the thickness of the sheet is about 1/10th that of the CRGO grade (i.e) 0.023 mm. Stage wise process chart for forming amorphous cores is as under

Pre Spooling and cutting

  • The Amorphous Ribbons are purchased from Metglas USA and they come in 5 ply arrangement. Each ply is 0.023-0.025 mm thick.
  • The 5 ply ribbons are then loaded on to 3 'de spoolers/de coilers ' on a fully automated cutting machine, the total ribbons now being 15 (3 x 5 ply). This machine has on line sensor controls to synchronise the speed of all the 3 de coilers.
  • Cutting for all the 15 Ribbons with different lengths (Perimeter of the exterior ribbon being highest) with a High Speed Tungsten Carbide Blade which is specially made for a life of 20,000 cuts. These blades are again ground for reuse.
  • The auto stacker present in the cutting machine carefully stacks all the cut amorphous ribbons and the material is sent further for the forming process.

Spooling and cutting

Lacing and Forming

  • The stacked cores are then placed on the specially made forming table which consists of a pneumatic fixture to hold the mandrel of the stacked ribbons and a hydraulic tool.
  • The stacked ribbons are then laced over a rectangular mandrel which forms the inner core dimensions. The core is then slowly built ('laced') layer by layer to form a rectangular shape as shown above which is almost similar to wound core making with conventional steel.
  • The exterior sheet of the core is protected by a Silicon Steel Strip of the exact width as that of the amorphous core ribbon. This is primarily done to support the flexible amorphous ribbon core structure. A highly skilled workman then spot welds the silicon steel strip and places a mandrel around the silicon steel strip with the inner core also supported by the rectangular mandrel throughout the process.
  • These pre formed cores are then sent in the Continuous/batch furnace and annealed at a controlled temperature with a strong magnetic field for 8 hours and then cooled to room temperature. Following this epoxy compound is applied on cores to bind them together and to have an edge finish.
  • The cores are then taken in for Core coil Assembly stage.

The rest of the process in AMDT is similar to Conventional Core Transformers.