The manufacturing of electromagnetic coils involves the winding method of an electrically conductive wire. In the winding process, the wire is given the shape of a helix, spiral, or coil. However, the determination of the dimension and shape depends on the particular purpose that the coil has to serve. The design of the coils also relies on some important parameters such as resistance, inductance, and magnetic field strength.
The applications that involve the interaction between the magnetic field and electric current, require electromagnetic coils. Electromagnets, inductors, transformers, and sensors are useful devices for these applications that involve electromagnetic coils.
Either electric current generates a magnetic field when passed through the wire of the coil, or an external magnetic field helps to generate the electric current in the wire by passing through the interior of the coil.
Machinery for Coil Winding Method
It is impossible to wind the coils by hand. To prepare the electromagnetic coils in a huge quantity, automated machinery with mass production ability is useful. Depending on the geometry and type of the coils, coil winding can be of different types such as orthocyclic, jumble, and helical.
As creating layers in a helix coil requires switching directions, therefore, the machines for helix coil winding should have the ability to move forward and backward. However, the manufacturers need to use ultra-fine wires for the preparation of these coils because, after certain layers, the structure becomes really tight.
The most optimal process for coil winding is orthocyclic winding where the upper layer wires take place in the groove of the lower layer wires. Manufacturers also focus on reducing the required space and material for the coil winding process in order to increase the efficiency of the coils. There should also be a good distribution of electromagnetic field strength and heat conditions across the coils.
Challenges for Winding Process:
The limited physical size of the devices is the most significant challenge that the manufacturers have to deal with. As the manufacturers have to fit the micro-coils within the devices, the coils must be very tiny. This occurs mainly with medical devices.
The other challenges for the coil winding process are-
- Insulation of the wires in order to avoid reaching the breaking point
- Tight spaces for winding the coils
- The machines should be able to manufacture the coils with high speeds
- To handle the wires that are not straight
Winding of the micro-coils requires near about 2000 turns and therefore, it is essential to reduce the thickness of the wire as much as possible in order to minimize the size of the coil. For this reason, most manufacturers use ultra-fine copper wire of 8 microns diameter. However, handling this type of thin wire is not an easy task. For instance, in order to connect two wires, the manufacturers can not depend on the traditional method of soldering and welding wires. Therefore, the manufacturers should use the Thermo compression bonding technology to have precise soldering at very high temperatures. Above all, the manufacturers need to use specialized equipment and state-of-the-art methods for the micro-coil winding process.