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Thermal bonding machines
Creating high-strength windings with selfbonding wire

Windings need to be of high strength. For this reason, under no circumstances may any of the windings be allowed to chafe against each other. This would result in the insulation being damaged or destroyed over time!

Windings must form a highly stable unit.

Which procedures are available?

  • Bandaging
  • Impregnation
  • Drizzeling
  • Vacuum impregnation
  • and thermal bonding

Thermal bonding uses selfbonding wire with a coating that liquefies at a defined temperature. On a coil, the individual windings, wound with selfbonding wire, initially lie loosely against each other. Although the windings touch, they are not yet connected to each other:


To bond the windings together, the coil is heated to the temperature at which the adhesive layer melts around the entire copper wire.

As soon as the required temperature is reached, the adhesive layers bond at the points of contact. The coil is then cooled down again.

The result is a stable unit in which the windings no longer have a chance to move against each other – perfect!

The coils/windings are thermally bonded to each other.

How do you perform the heat-up process?

  • with hot air blowers – but is this a stable and reproducible process? No.
  • in a heating oven – but is this fast? No.
  • by current heating – but can this be reproduced quickly and reliably? Yes!

Heating with electric current is ideal for the very well controllable and fast process. Only the target temperature has to be specified – the bonding system heats the wire fully automatically and reliably.
As soon as the bonding temperature is reached, the adhesive layer melts and the individual wires adhere/bond to each other.

The thermal bonding process could be stopped abruptly as soon as the set target temperature is reached. After all, the prescribed temperature has been reached, which enables the wires to be bonded.
But staying at the target temperature for some time afterwards can also be advantageous. The temperature distribution in the winding can thus become even more homogeneous, with the result that the resist wires are connected to each other at as many contact points as possible.


  • Bonding systems with direct current
  • Bonding systems with alternating current
  • up to 2,500 A
  • up to 1,000 V
  • Bonding systems in combination with testing technology, such as surge voltage test, high voltage test, partial discharge test, …
  • Mechanical bonding cells or rotary switching tables, if required with:
    • Winding head shaping
    • Winding head press
    • Grooving mandrel
    • other custom additional attachments

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