Winding technology is a crucial part of the manufacturing of electromagnetic coils.In order to prepare electromagnetic coils, a conducting wire is wound around a core in the shape of a helix or spiral. However, depending on the purpose of the use, manufacturers determine the design of the shape and dimensions. There are also some parameters that can influence the design of the coils such as the strength of the magnetic field, inductance, and resistance.Depending on the winding process, electromagnetic coils can be of two types such as bifilar-wound coil and trifiler-wound coil. When there are two parallel windings in a coil, the coil is the bifilar wound-coil. Manufacturers use two insulated conductors in this winding process.
In order to make the electricity flow in the same direction and to magnify potential differences, some bifilar coils consist of adjacent coils.On the other hand, another winding processisused so that the electricity flows in the opposite direction.Therefore, these two winding processes generate equal and opposite magnetic fields so that the net magnetic field becomes zero. Through this neutralization of the negative effects, the self-inductance of the coil becomes zero.The reception and transmission magnetics of Ethernet cables use this arrangement and you can see this arrangement in laptop power supply, USB, and HDMI cables. Due to negligible parasitic self-inductance, bifilar wound-coils act as wire-wound resistors for construction.On the other hand, three strands of wire are spooled together in order to manufacture a trifiler-wound coil.
The Advantages of Bifilar and Trifilar-wound Coils:
You should always choose bifilar and trifiler wound coils for several reasons such as-
- When your device requires electricity flow in both equal and opposite directions, these bifilar and trifiler-wound coils are effective.
- Compared to a wire-wound resistor, a bifilar-wound coil is more effective.
- In the stray magnetic flux, when there is a requirement for the removal of energy stored.
The Manufacturing Challenges:
The demand for micro-coils is increasing due to the need for miniaturized modern equipment. However, in order to make bifilar and trifilar wound coils, manufacturers are facing several challenges such as-
- The need for profitable mass production.
- It is a challenge for the manufacturers to prepare oxidization free highly reliable connections.
- There can occur damage in the wind isolation and therefore, manufacturers need to take care of the safety of the manufacturing process.
- It is also important to provide tight tolerance in the micro-coils.
- Manufacturers also need to provide continuity in the physical and electrical characteristics of the micro-coils.
- High quality needs to be maintained in the manufacturing process for the longevity of the micro-coils.
- Manufacturers also require to develop automated manufacturing processes in order to minimize human errors.
In order to prepare miniaturized bifilar and trifilar coils, it is important to wind ultra-fine wires around the core. Traditional soldering-based connection methods are not effective to provide oxidization-free connections. Therefore, modern manufacturers use thermal compression bonding to connect two ultra-fine wires of similar and different diameters.