Everything to Know about Coil Winding Process

The Basics of Coil Winding Process:

The coil winding process is the heart of the micro-coil manufacturing process. The process involves the winding of an ultra-fine wire around a core. An ultra-fine wire can be wound to prepare micro-coils of different shapes. Initially, through the insulation process, the ultra-fine wire is coated or isolated in order to ensure the protection of the wire. Then the isolated wire is wound around a pin or core. This winding procedure develops an electromagnetic induction.

To prepare micro-coils, most winding processes involve insulated copper wire. For the insulation process, the extremely effective material is a polyamide base material. However, there are many other materials that can provide effective resistance to temperatures and breakdown voltages.

The shape of the Coils:

Depending on the purpose of use, the shape of the micro-coils can be different. This is because of the fact that different shapes of micro-coils provide different electrical values. When you are designing the shape of a micro-coil, the measurement of the inner and outer dimensions is critical. The winding process can provide different shapes of the micro-coils such as round, elliptical, and rectangular.

Winding Process for Medical Sensors:

Size is the most important parameter for the winding process of medical-grade coils. In order to insert the coils in several body regions, the coils have to be very tiny in size. For instance, the insertion of a coil into the vein requires a coil that is smaller than 0.8 mm, including the insulation of the wire. Due to this tiny size, highly specialized and built in-house machinery is essential.

With the help of the winding process, an insulated copper wire around a pin or core prepares a coil. However, the micro-coils can be coreless and self-bounded this means during the winding process, the coil is tied to itself. The winding process can occur around rectangular or cylindrical support. Then after the completion of the process, removal of the rectangular support results in a rectangular shaped coil.

Due to the size constraint, manufacturers need ultra-fine wires that are smaller than 8 microns. This will help to prepare thinner and suitable coils for medical applications.

Manufacturing Process of Micro-Coils:

When you are developing coils for miniature sensors, you should have-
i) a great understanding of the winding process for miniature coils,
ii) specialized equipment to conduct the winding process.

You can not just buy the machinery for winding micro coils from the market. Instead, depending on the requirements, you need to design a machine and develop that from scratch. Therefore, whether you require machinery for the soldering process or wire terminals, you need to create in-house and special machinery for everything related to miniature coils.

In order to provide connectivity within tiny medical devices and to produce inductive components, it is essential to use ultra-fine wires in micro-coils. On the other hand, handling ultra-fine wires require several innovative technologies. These technologies involve a variety of methods in order to work with copper and other metal wires. As the diameters of the ultra-fine wires are very small and it can be up to the size of 59 AWG (9 microns or 0.00035 inches) that is five to ten times thinner compared to human hair, therefore, handling these tiny wires involve non-trivial challenges. The main challenge of the manufacturing process is that the final product should fulfill strict tolerance requirements. Apart from this, there are also several physical and environmental factors that create constraints for the final shape of the micro-coil.

The machinery that is used during the winding process should be able to control and monitor the position and tension of the wires. For this reason, manufacturers need to develop custom-made machinery that involves a control system and state-of-the-art micro-motion technology.

Thermo-Pressure Bonding Technology:

An important part of the manufacturing process is the connection of ultra-fine wires. It has been proven that the traditional soldering methods are not useful to connect ultra-fine wires. Due to this reason, an innovative modern technology, thermo-pressure bonding technology is developed. With the help of this technology, manufacturers can effectively join two ultra-fine wires. Even if the ultra-fine wires differ in diameters or metals, this technology is useful for ultra-fine wire connections. This technology not only helps to provide durable and reliable joints but also offers strain-free and corrosion-free joints.