Micro-coil winding technology is the core process to manufacture electromagnetic micro-coils. Apart from building the micro-coils, this process is also responsible for generating an electromagnetic interaction within the micro-coils.
If you are not familiar with micro-coils, these coils are essential components of many modern electronics and medical devices due to their electromagnetic properties.
A coil manufacturer should employ the coil winding technology in a proper way to meet ultra-strict tolerance limits and high-quality standards for the coils. Let’s learn about micro-coil winding technology in detail-
Micro-Coil Winding Technology
Micro-coil winding technology involves twisting or winding an extremely thin electrically conductive wire around a core, pin, or any geometrical support. Considering the importance of maintaining the tiny size of the micro-coils, coil manufacturers use ultra-fine wires of 8 to 9 microns in diameter.
Another thing that manufacturers need to be careful about is that the ultra-fine wire should never touch itself during the winding process. By using supports or cores of different geometrical shapes, manufacturers can shape the micro-coils differently, such as round, rectangular, and helix-shaped coils.
Before winding the ultra-fine wires around a core, manufacturers insulate or coat the wires by using a specific coating material. This insulation will prevent a wire from coming into contact with itself. Manufacturers then wind the insulated wires according to the requirements.
Polyamide is commonly used to insulate ultra-fine copper wires. Apart from copper wires, manufacturers also use other metal wires, such as gold, platinum, aluminum, etc., depending on the required breakdown voltages and resistance to high temperatures.
Different Coil Winding Methods
Micro-coil winding methods can be of different types. Manufacturers can use different procedures to build micro-coils depending on the application area, orthocyclic winding method and helix coil winding method.
The winding of helix coils involves switching directions after every layer, whereas orthocyclic coils are wound by placing the wire of the upper layers in the channels between two wires of the lower layer.
Depending on the required electrical values of the coils, manufacturers can shape the coils differently., such as elliptical, round, and rectangular. Besides designing the shape of the coils, manufacturers also need to precisely decide on the inner and outer dimensions to maintain a proper size for the coils.
Challenges and Solutions
Micro-coils are critical components of tiny medical devices. These devices require miniature coils. For instance, in the case of inserting medical sensors inside the veins of a person, micro-coils have to be very small to fit into the tiny sensors.
While it is essential that medical coils have a diameter below 0.8 mm, only the use of ultra-fine wires (0.8 microns in diameter) can solve this size constraint. Joining two ultra-fine wires is again a big challenge that coil winding specialists face.
Whereas traditional connectivity methods are ineffective in joining tiny ultra-fine wires and cause several issues like wire damage, extreme heat spreading, corrosion, strain, etc., the Thermo Compression Bonding method offers the ideal connectivity for ultra-fine wires and offers reliable, strain-free, and corrosion-free joints.
Manufacturers should also use specialized and built-in-house equipment to conduct the coil winding process properly.
