4 Key Features to Look for in a Miniature Coil Supplier

ECN Magazine published ‘4 Key Features to Look for in a Miniature Coil Supplier’ The article reviews four key areas of focus OEMs need to review with a potential supplier to ensure the company is the right choice for their specific project. Click the link below to view the full article.


With the increasing popularity of miniature coils made with ultra-fine wire winding, finding a supplier that can suit all of a medical device manufacturer’s needs can be significant to reduce time to market and save costs.

Miniature coils made with ultra-fine wire winding are quickly growing in popularity in the medical device industry. With gauges ranging from AWG 45 (.0018”) to AWG 60 (.000309”), these wires can be as small as 1/10th the diameter of a human hair, allowing for noteworthy miniaturization in charging and receiving devices.

Miniaturization provides significant benefits to design engineers. In addition to real estate savings and enhanced design flexibility, the use of ultra-fine wire makes it possible to create smaller and more accurate computer assisted surgery and medical device navigation technologies for intervention or tracking. These smaller technologies  are:

  • Less invasive or implantable
  • Safer
  • More precise
  • Capable of enhanced sensing

As one might anticipate, the precise winding, handling and manufacturing of wire so small and delicate that it is invisible to the human eye requires significant technical expertise. Even the smallest of technical missteps can create significant performance issues.

To identify a miniature coil supplier who offers the very latest in ultra-fine wire capabilities for maximum design flexibility while also meeting the strict performance parameters required to ensure success with these extremely delicate components – be sure to identify companies who provide each of the four key features below.


58 AWG Wire Expertise


While there are many providers worldwide who work with “ultra-fine” wire in the 45 AWG to 55 AWG range, there are only a select few who have the technical expertise and specialized machinery required to work with 58 AWG ultra-fine wire. Every aspect of handling and assembling technology of this size requires very specialized technology and training.

The ability to use ultra-ultra fine 58 AWG wire provides important benefits for design engineers. Specifically, 58 AWG ultra-fine wire generates up to 50% space savings when compared to the use of 52 AWG wire and up to 30% space savings when compared to the use of 55 AWG wire. These real estate savings allow for the creation of smaller medical technologies and also provide engineers with significantly enhanced options in the design of new navigation technologies.


Quality-Focus: Experience, Facilities and Processes


Is essential to identify a partner with a top-to-bottom commitment to state-of-the-art quality. A good way to do this is to take a close look at a prospective supplier´s experience, facilities and processes.


A supplier with deep expertise in the medical device industry gives you the peace of mind of knowing they have an understanding of the strict requirements performance standards required. Ask a prospective miniature coil supplier how many medical device companies they have worked with? Have they worked on global projects? Do they have material selection to integrated component expertise on a wide number of projects? The more extensive their expertise, the better.


When dealing with sensitive ultra-fine wire that is as small as 1/10th the diameter of a human hair, state-of-the-art clean room facilities are a must. It is best to identify suppliers with clean rooms that are not only top-of-the-line, but also highly flexible to meet your evolving needs. Be sure to ask about ISO certifications, clean room classification as well as flexibility (can the room be divided in two for example with each part working at different classification). It is also helpful to ensure the clean room is flexible and scalable with significant equipment redundancy to ensure capacity for quick turnarounds.


It is also key to ensure that a prospective miniature coil supplier has an established project management method designed to ensure optimal outcome. Inquire into their process to ensure it allows for proper quality checks as well as for flexibility when required for your unique project.


Associated Expertise


To ensure optimal performance, a quality supplier must provide more than ultra-fine wire winding capability. They must also provide the associated skills necessary to handle, solder, test and process such immensely delicate coils. In particular, look for a supplier who offers the following:

Specialized Machinery

Inquire as to whether a potential supplier has created ultra-precise winding and dereeling equipment specially designed to handle ultra-fine wire. It will also be important that they have cutting-edge microscopic soldering technology and CCD camera equipped microscopes to provide top quality inspection, training and dimensional conformity verification at 40x to 50x magnification.


In addition to ISSO 9001:208 and ISO 13485:2000 certifications for medical device manufacturing, it is very helpful to make sure personnel at a prospective supplier have undergone extensive training in ultra-fine wire handling. Look to see that employees have J Standard Solder/NASA Soldering: ISO 14644 certifications. The best suppliers will not only have personnel qualified in handling ultra-fine wire- they will also have certified instructors in expert handling on their staffs.

Extensive Capabilities and Value Added Services

Due to the highly specialized nature of handling ultra-fine wire, a quality supplier of miniature coils will offer not only coil production but also extensive related capabilities and value-added services including:

  • Testing
    • Full range of electrical tests for optimal quality and performance including resistance, dielectric, phase, inductance testing.
  • Range of Product Options
    • A wide range of termination and connection options including surface mount / PCB, wire to wire and wire to cable.
    • Multiple primary wire and jacket filar materials including ETFE, PFA, FEP, PEEK, Polyethylene, and Polyurethane
    • Helically wound micro-gauge coils for superior flexibility, allowing multiple paths for cameras, ablations, fluids, air, etc.
    • These diverse options should be accompanied by significant stock on hand for rapid prototyping in order to speed time to market.
  • Value Added Services
    • The ability to reduce costs and streamline supply chains by incorporating miniature coil design, assembly and packaging into a single supplier. This requires in-depth expertise of the entire production process from material selection to completed component integration for optimized supply chains and manufacturing performance.

Cutting Edge Winding Capabilities: Angular Winding


Finally, it is key to ensure that a prospective supplier is up to date on the very latest in ultra-fine wire winding. Today´s top suppliers not only provide 58 AWG ultra fine wire- they also offer advanced angular wire winding configuration.

Angular winding configuration features wire at up to a 55° angle (known in the industry as the “magic angle”) to the coil axis which has been proven to improve signal intensity for optimal sensing performance.This unique configuration greatly simplifies design processes. Previously, miniature coils required the addition of some element that would position the coil precisely at a 55° angle to the coil axis. Now the real-estate and cost associated with this extra element are no longer required as the wire itself is already wound at a precise 55° angle to the coil axis. Removing the need for an additional angling element ensures superior performance as

less components provide fewer areas for error. It also makes multidimensional sensing possible with a single axis coil.


In summary, miniature coils provide design engineers with a large number of design and performance benefits. The highly delicate nature of the wire requires finding a provider with the highest level of specialized technical knowledge. Be sure to investigate whether potential suppliers offer 58 AWG wire, have state-of-the-art clean room facilities, possess demonstrated expertise in all related technologies and processes, and are up to date with the very latest developments (like angular wire winding). Diligent research into these four key areas will uncover a miniature coil supplier who can provide optimal performance and design flexibility.

About the Author

David Anderson


Specialties: Application engineering, full understanding of manufacturing process related to design.

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