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Canted Coil Springs For Conduction

Flexforce Canted coil springs, can be used as effective electrical conductors. They can provide reliable current conduction despite challenges such as vibration, dynamic conditions, and shock loadings where other conductor solutions would fail.

Situations That Pose a Challenge for Conduction

Certain operating conditions can make it challenging to achieve a solid connection for conduction. For example, vibration and shock loadings, such as those experienced in downhole tools for the petrochemical industry, can cause more traditional electrical connections to eventually work loose and risk the integrity of signal and power transfer. 

Any time there is a high probability of motion, such as EV/HEV battery pack connections, there is also a risk that the integrity of the electrical connection could be compromised. In the power industry, issues can arise with heat and reliability for high-current applications that perform conduction, grounding, and isolation.

Rotating parts, high temperatures, and variations in loadings are also challenging for maintaining electrical connections and common to wind energy applications involving turbines. In addition, rotating parts in robotic end grippers and similar automation equipment pose similar issues. 

Implantable devices, such as neurotransmitters and pacemakers, require electrical connections that must also be highly reliable, lightweight, and compact. In addition, lightweight design approaches are critical for many applications, including unmanned vehicles that must be lightweight to maximize their battery-constrained range. 

And some applications, such as semiconductor fabrication, need to take advantage of solutions that can perform multiple purposes, such as conduction combined with latching/holding/locking or EMI shielding.

Canted Coil Springs

Our Canted coil springs, also known as slanted or slanting coil springs, are often used as electrical conducting springs to achieve high integrity connections for applications such as those just described. However, several factors make these springs different, starting with their ability to maintain consistent force over a wide range of deflection. 

The Individual coils that make up these springs maintain contact with the mating surface despite surface irregularities, misalignment, tolerance variations, and dimensional changes. In addition, they experience little to no compression set and are ideal for oddly shaped cross-sections.

When used as electrical conducting springs, the individual coils serve as multiple contact points for electrical conduction and grounding; essentially, each coil is a contact point. As long as one coil remains in contact with the surface, then the electrical connection is maintained.

Benefits of Canted Coil Springs for Conducting

There are numerous advantages over more traditional approaches when canted coil springs are used for electrical conduction. For example, canted coil springs can be designed to meet specific electrical requirements in addition to being manufactured from materials with high conductivity. Varying parameters such as spring diameter, wire diameter, coil height, canted angle, and the number of turns make it possible to tune amperage and electrical resistance for optimized solutions. In addition, platings such as gold or silver can be used to achieve ultra-low impedance.

Because of the extensive surface area of canted coil springs, they can transmit high power levels while generating less heat than traditional solutions. As a result, they provide outstanding heat-to-current carrying capacity even in extremely high temperatures. This same aspect is also essential in implantable devices where heat generation must be minimized for patient safety. In addition to their conducting capabilities, canted coil springs can serve as excellent EMI/RF shields for applications such as downhole tooling in oil exploration.

Canted coil springs support SWaP (space, weight, and power) requirements while reducing system complexity. This system simplification is often seen when they are used for mechanical fastening (latch, lock, or hold) in addition to electrical conduction. They make it possible to achieve far greater contact densities in smaller spaces than equivalent conductivity solutions. And one of the outstanding features of canted coil springs, as alluded to earlier, is their ability to provide specific force levels for fastening that include low force insertion.

As discussed in the previous section, these springs are able to maintain contact with surfaces despite factors such as impact and shock loadings, angular misalignment vibration, dimensional changes, and mating surface irregularities. In addition, they maintain performance in other harsh conditions by using materials and platings that are corrosion resistant. And canted coil springs, when designed and installed correctly, can reduce the possibility of conductor fatigue failure in relation to multiple insertion/removal cycles. Their minimal compression set also contributes to their extensive operational life.

Finally, canted coil springs are easy to clean and sanitize if needed for medical, pharmaceutical, food, and beverage applications. 

Conclusion

Canted coil springs are used as highly reliable electrical conductors in industries such as medicine, transportation, aerospace, semiconductor fabrication, industrial, energy, and defense. From surgical bones saws to guided weaponry, canted coil springs have provided dependable, effective conductivity solutions. 

 

Advanced EMC FlexForce Canted Coil Springs

For economical, reliable, SWaP-friendly conductivity solutions, Advanced EMC FlexForce canted coil springs may be the answer. The experts here at Advanced EMC can help you determine if a canted coil spring conductor will meet your design specifications and constraints. And if it does prove to be what you need, they will be there every step of the way until you have the conductor your design requires.

To learn more, you can also read 7 Things to Know About FlexForce Canted Coil Springs.

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Canted Coil Springs for EMI/RF Shielding

Canted coil springs are an effective, reliable solution for some of the toughest EMI/RF shielding challenges. But what makes them different from other options, like wire mesh over polymer and finger springs?

 

What Are Canted Coil Springs?

Sensitive electronics need protection against EMI (Electromagnetic Interference) , RF (Radio Frequency), and crosstalk, and they need to avoid interfering with other electronics. Among the EMI/RF shields on the market are canted coil springs. These springs get their name from the angle at which the individual coils are set. This allows them to achieve a consistent, highly predictable force once installed, which makes them ideal for latching, locking, and holding as well as spring-energized seals. As just mentioned, they also provide highly reliable EMI/RF shielding made possible in part because each coil serves as a contact point for conduction or grounding. 

Where Canted Coil Springs Are Used for EMI/RF Shielding

Canted coil springs are used in a variety of applications where they provide shielding for data and signal transfer, including 

  • Antenna bases
  • Power management systems
  • Electronic enclosures
  • Waveguide flanges
  • Cabling
  • Connect/disconnect assemblies
  • Coaxial and electrical connectors

Whenever EMI/RF shielding is involved, there are critical national and international standards that must be complied with. These standards come from several different organizations, including the following:

  • CISPR (Comité International Spécial des Perturbations Radio), dealing with emission and immunity as well as test methods and the equipment used for testing
  • IEC 61000 (International Electrotechnical Commission) focusing on EMC (Electromagnetic Compatibility)
  • ISO (International Organization for Standardization) standards specifically for automotive EMC concerns and covers road vehicles, earthmoving equipment, and forestry and agricultural machines
  • SAE (Society of Automotive Engineers) EMC Standards Committee
  • EN (European Norm) standards concerning unwanted electrical emissions and immunity to unwanted electrical emissions
  • FCC Part 15 (Federal Communications Commission) for unlicensed radio-frequency transmissions
  • MIL-STD 461, 464, and 469 (Military Standard)

For a product to be sold on either the national or international market, it must be in compliance with relevant standards. To learn more about canted coils, click this link to read the most common questions about canted coil springs.

 

Benefits of Canted Coil Springs for EMI/RF Shielding

There are several advantages to using canted coil springs for EMI/EF shielding, starting with their ability to serve two or more different purposes in a single design. 

Multipurpose Mechanical and Electrical Solution

Canted coil springs can be used for multiple purposes in a single application: they also perform latching, holding, and locking functions. They do so with highly predictable forces and almost no compression set. When they are designed correctly, these springs can provide precise insertion and breakaway forces. Canted coil springs perform these mechanical functions without the use of tools and can significantly simplify a design when used as a multipurpose solution (i.e., latching and EMI shielding).

Lightweight and Flexible

Canted coil springs are extremely lightweight and compact, which can make them an excellent option for SWaP (Size, Weight, and Power) constrained applications. Their flexibility allows them to be used with many geometries other than circular that would be otherwise challenging to shield. 

Geometric Options

Standard spring wire is available in wire diameters from 0.25 mm (0.010 inches) to 1.50 mm (0.059 inches). Standard coil widths range from 1.5 mm (0.039 inches) to 15 mm (0.591 inches). However, there are custom options available for wire diameter and coil width. The angle at which the coils are oriented can also be specified. Finally, the coil pitch can be varied, and is usually quite dense for EMI/RF applications.

Material and Plating Options

There are several different material and plating combinations available for canted coil springs. The most commonly used spring materials include …

  • Stainless steel
  • Beryllium copper
  • Zirconium copper
  • Inconel
  • Hastelloy
  • Platinum iridium.

These materials can be combined with platings such as nickel, silver, gold, and tin. Platings are especially useful when the springs may be exposed to corrosive environmental conditions.

Impedance Tuning

While canted coil springs already work across a very broad spectrum of EMI interference, they can also be tuned to very specific impedance specifications. This can aid not only in device performance but in achieving compatibility with the appropriate EMC/RF standards.

Reliability

Because canted coil springs can provide a near-constant force, they will remain in contact with surfaces extremely well. This is true even when subject to vibration, shock, and impact loads as well as dimensional changes due to temperature fluctuations. Canted coil springs do an excellent job of compensating for hardware variations, surface irregularities, and angular misalignment, leading to highly reliable performance even in difficult operating conditions.

Conclusion

If you are looking for an economical, effective, and reliable EMI/RF shielding solution, consider the use of canted coil springs. And the experts here at Advanced EMC can help you choose the right spring options, tune it to the impedance you need, and ensure that your design will comply with the right standards. Contact us today to learn more about our Flex-Force canted coil springs.