Micro Coil Winding for Medical Devices

One of the major challenges facing the mechanical designer of invasive medical devices is the need for miniaturization. Miniaturization serves several purposes; reaching otherwise inaccessible regions in the body, minimizing disruption of regular body functioning, minimizing energy consumption, and increasing the lifetime of implanted components.

These size constraints pose multiple challenges, both in the manufacturing and in the connecting of these components to each other and their support systems. Many of the designs of these devices rely on micro coils which in turn require advanced techniques for their winding and connections.

Medical Micro Coil Winding

Standard equipment used to wind regular-sized coils cannot be used to serially wind micro coils, necessitating the development of specialized equipment. With in-house engineering, Benatav has developed state-of-the-art methods and equipment that enable the winding of micro coils to an unprecedented extent.

To manufacture a micro coil with as many as 2000 turns, the wire thickness needs to be greatly reduced. The thinnest available copper wire currently measures 8 microns (0.0003 inches). Benatav is one of the few companies in the world working with such fine wires and is even working on producing insulated wires smaller than 8 microns.

Benatav has developed advanced methods for handling wires of any diameter, down to the finest serially manufactured size of 59 AWG (9 microns, 0.00035 inches). Handling wires that may be 5-10 times thinner than a human hair poses a significant challenge, especially when the desired shape of the wound coil is constrained by various physical and environmental factors, as well as strict tolerance requirements.

Using our custom micro-machining technologies, we manufacture coils with over 1000 windings that are smaller than the head of a pin. However, connecting the ultra-fine wires that make up these tiny coils presents further challenges.

Connecting Micro Wires

As micro coils are just one component in a larger system, their electrical connection to these systems poses additional challenges. Traditional solder-based connections are inadequate for the task, as they result in undesired side effects such as oxidation, inferior conductivity, and low durability.

Ultra-fine wires are too thin to be welded or soldered using traditional methods, as this would destroy the wires. To overcome these problems, Benatav has developed a proven, cutting-edge thermo-pressure technology that enables precise soldering with tight tolerances at very high temperatures.

Benatav’s innovative thermo-pressure bonding technology provides highly reliable, corrosion-free, and strain-free connectivity without the drawbacks associated with soldering. This simplifies manufacturing processes and reduces costs. Thorough testing of the technology in a wide variety of customer environments, along with its implementation in several production processes, has proven its readiness for integration into mass serial production while meeting the standards required by medical applications, including both disposable products and lifelong implants.

Typical Medical Micro Coil Use-cases

A miniature coil manufactured by Benatav for example, may serve as the navigation component in a cardio-vascular catheter performing cardiac ablation which serves as a key element in a disposable catheter. This micro coil must be mass-produced with high and predictable quality at a reasonable cost.

Our technologies for winding micro coils and connecting them open up a vast array of possibilities to medical device designers. Miniature coils, for example, can be used to provide capabilities such as:

• Transferring control, monitoring, and logging data to/from miniature implants
• Transferring energy to implants requiring battery charging or electrical charge input to activate and operate their systems
• Radiating energy for RF treatments, heat treatments, or electromagnetic radiation-based treatments
• In-vivo magnetic navigation, employing a local or external magnetic field

Medical Micro Coil Applications

The applications that can benefit from miniature coils technologies and ultra-fine wire connectivity technologies include:

• Diagnostic applications: wireless communications with miniature implants serving as sensors, whether physiological (blood pressure, heartbeat), glycemic, or flow (blood, respiratory)
• Active implants applications: monitoring/controlling of miniature implanted pace-makers, or deep brain stimulation components in pain management implanted devices
• Therapeutic applications: end devices in electrophysiology treatments (cardiac, neural, brain) or electricity-based ablations (microwave and RF)
• Navigation and orientation applications: targeted drug delivery, targeted radiation catheters, stents positioning, highly-accurate ablations, implanted markers, inter-body tagging, as well as endoscopic, gastroscopic, colonoscopic, laproscopic, and other similar procedures
• Temperature measuring applications: chromel-constantan miniature thermocouple (type E), based on thermo-pressure molecular bonding technology
• Hearing aids: connecting micro-coils to their operating system on a PCB, using a mediating thicker wire, which can withstand soldering

Contact us to discuss your micro coil requirements

Benatav’s specialist technologies open up a limitless range of possibilities for designers of miniaturized medical equipment and other industries. Discover the benefits of Benatav’s unique medical micro coil winding technology. As awareness of our thermo-compression bonding grows, we anticipate that its applications will become increasingly widespread.

Whatever your micro coil requirements, our extensive specialist experience in micro coil technology means that we have likely already solved any issues that may prevent us from producing your coils at highly competitive rates