by Sara McCaslin, PhD Sara McCaslin, PhD 1 Comment

Most Common Questions about Canted Coil Springs

Here are answers to seven of the most common questions asked about canted coil springs.

Where Are Canted Coil Springs Used?

Canted coil springs can be used in many different ways, but many are not aware of exactly how versatile they are. In the medical industry, they are used to shield equipment from crosstalk that could compromise the integrity of data. The automotive industry depends on canted coil springs to achieve solid mechanical and electrical connections while reducing weight and minimizing the complexity of assemblies. 

In the oil and gas industry, they are used to achieve both electrical and mechanical connections in the rugged environment of downhole tools. Canted coil springs protect sensitive equipment from lightning strikes in the aerospace industry. And those are just a few examples of how they can be used.

What is a Canted Coil Spring?

Traditional springs have all the coils perpendicular to their longitudinal axis. Canted coil springs, on the other hand, have the individual coils parallel to each other and at an angle to the longitudinal axis. Because of how the coils are oriented, these springs can effectively serve a wide range of uses that traditional springs cannot.

Are There Any Other Names for a Canted Coil Spring?

Yes, as a matter of face there are. Canted coil springs are also called slant coil springs and cant coil springs, both in reference to the angle (or cant) at which the coils are parallel to each other.

What Makes a Canted Coil Spring Special?

Because of the cant of the coils, these springs have a flat load curve when compressed–which is rather unusual for a spring. This means that the load generated as these springs are compressed is predictable through their wide deflection range. 

What Can Canted Coil Springs be Used For?

Canted coil springs have four specific areas of application in which they excel: energizers for spring-energized seals, mechanical connectors, multi-point electrical connectors, and EMI/RF shielding.

Spring-Energized Seals

Canted coil springs are one of the options when specifying a spring-energized seal. Spring-energized seals provide outstanding performance in spite of issues such as uneven mating surface,  hardware gaps, runout, eccentricity, out of roundness, and seal lip wear. 

In that context of spring-energized seals, canted coil springs generate a flat load curve that in turn keeps friction at a predictable, constant level. This is extremely important in sealing applications for which friction and torque are critical to the functionality of a seal. In addition, canted coils do not experience compression set. Canted coil spring energizers work best when there are moderate to high speeds involved and are ideal for situations where friction needs to be highly controlled.

Mechanical Connectors

First, canted coil springs work well for latching, or fastening two parts together so they can still be disconnected when needed. They also work extremely well at locking, where two parts are permanently “locked” together. Holding is another task for which canted coil springs excel: two parts can be aligned and retained, but with sliding possible. Sliding is highly controlled by spring force generated when the canted coil spring is deformed.

In this type of application, canted coil springs can be fine tuned to achieve highly specific insertion and removal forces. This is made possible by the nearly constant spring force that these springs generate over their deformation range.

EMI/RF Shielding

One of the more interesting applications of canted coil springs is their ability to provide EMI/RF shielding.  Their electrical properties can be adjusted to meet specific impedance requirements to achieve optimal shielding for certain ranges of interference, including both conductive and radiated. And they work extremely well at shielding from crosstalk.

These springs can easily adapt to even the most uneven and irregular shapes, allowing them to provide a consistent level of shielding, and can be used with connect/disconnect assemblies, waveguide flanges, rectangular electronics enclosures, and both radial and coax connectors.

Multi-point Electrical Conductors

Canted coil springs can also serve as multi-point electrical conductors. Because surface area provided by the canted coils, they provide a cooler operating temperature which can be critical in certain designs, including those where space is highly limited. Canted coil springs can serve as both conductors and grounds, in both static and dynamic applications. Their multi-point contact system means they can keep electrical contact even in extremely harsh conditions, including those where vibration and shock are common. 

What Kind of Materials Are Canted Coil Springs Available In?

The three most common materials for canted coil springs are:

  • Hastelloy
  • Inconel
  • Elgiloy
  • 300 Series Stainless Steel (e.g., 316, 316L, 302)
  • Copper alloys

In addition, they can be nickel, silver, or gold plated if needed. 

If there is going to be extremely high temperatures and/or exposure to corrosive media, Elgiloy is typically recommended. For shielding or use as a multi-point conductor, stainless steel and copper alloys work extremely well.

What Kind of Options Are Available for Canted Coil Springs?

The basic options for canted coil springs outside of those related to materials are …

  • Wire diameter
  • Coil size (width and height) 
  • Coil cant angle 
  • Number of independent coils
  • Inner and outer diameter of the spring

By adjusting these parameters and material selection, specific performance goals can be achieved.

Conclusion

Canted coil springs are useful in so many different applications, and their performance is fully proven in the field. Whether you need highly reliable spring-energized seals for use in vacuum conditions, locking components for orthopedic implants, a way to protect rectangular electronics enclosure from a specific range of interference, or a multipoint conductor that also serves as a latching connector, canted coil springs are an excellent option.

And remember that Advanced EMC offers FlexForceTM canted coil springs. Our engineers can work with you to find the right combination of characteristics and properties to meet the needs of your application. Contact us today!

 

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

7 Things to Know About FlexForce Canted Coil Springs

FlexForce canted coil springs have special characteristics that make them useful in a variety of applications, ranging from locking components together in an orthopaedic implant to providing an energizer for mission critical aerospace applicants. In this blog post, we will introduce seven key facts about FlexForce canted coil springs that you need to know.

Are a Specific Design for Springs

Canted coil springs, also known as slant coil or cant coil springs, are springs that have the individual coils set at an angle to each other, rather than having them all parallel. This coil configuration significantly impacts the performance of these springs and makes them ideal for a wide range of uses.

What makes canted coil springs different from other types is the fact that they have a flat load curve when they are compressed. Because of this, canted coil springs generate predictable loads throughout their wide deflection range.

Can be Used as Mechanical Connectors

Canted coil springs are ideal for applications that involve latching, locking, or holding to connect two components (also known as detent mechanisms). Latching involves fastening two parts together so that they can still be disconnected when needed. Locking creates a permanent connection that can only be broken by damaging the sea. Holding, on the other hand, both retains and aligns parts and makes sliding possible via the controlled spring force. 

Canted coils are commonly used to connect two mating surfaces in a highly predictable, repeatable fashion thanks to the flat load curve. When canted coil springs are used, the insertion/removal force can be engineered to a high degree of accuracy.  And when used as a latching, locking, or holding connector, FlexForce canted coil springs provide a lightweight, high strength option that can be used for practically an infinite number of cycles.

Can Provide Exceptional EMI/RF Shielding

One of the common uses of canted coil springs is their ability to effectively provide EMI/RF shielding. Furthermore, the electrical properties of these springs can be customized to provide more optimal shielding against certain ranges of conductive and radiated interference.  

Add to this the fact that they can adapt to irregular and uneven shapes to provide consistent shielding, and it is easy to see why they are a common choice for applications that need to be protected from harmful electromagnetic and radio frequency crosstalk interference.

Can Act as a Multiple Point Electrical Conductor

Some designs depend on multiple electrical contact points, which a canted coil can provide. Using a canted coil spring for electrical connections results in a reliable connection that results in a cooler operation temperature. It allows engineers to manage more power in compact spaces and provides both conducting and grounding capabilities in both static and dynamic applications. In addition, canted coil springs as electrical conductors can perform in some of the harshest operating environments that may involve vibration and shock. It should come as no surprise that canted coil conductors are often used in medical applications inside the human body.

Can be Used with Spring Energized Seals

Canted coil springs work extremely well as the energizer in spring-energized seals. Because of the energizer, spring energized seals are able to maintain contact with the sealing surface, even if issues such as out of roundness, uneven mating surface, runout, hardware gaps, eccentricity, or seal lip wear are present. 

The flat load curve of these springs also means that friction stays fairly consistent in dynamic sealing applications. This makes them ideal for sealing situations that involve critical friction and torque specifications. In addition, canted coil springs are very unlikely to experience compression set. 

Available With a Range of Options

There are several options for canted coil springs. They are available in varying levels of spring force: light, medium, and heavy. And canted coil springs come in both standard and custom sizes. As to the spring wire itself, they are available in wire diameters between 0.25 mm (0.010 inches) and 1.50 mm (0.059 inches). As to the coil width, they come in sizes ranging from 1.5 mm (0.039 inches) and 15 mm (0.591 inches). However, designs can be highly customized if needed.

Finally, the three most common wire materials are Hastelloy, stainless steel (usually 300 series), and copper alloys. For use as a conductor or EMI/RF shielding, stainless steel is recommended. For applications that involve high heat and corrosive media, Hastelloy and Elgiloy may be recommended. Also keep in mind that these canted coil springs can be obtained with nickel, silver, or gold plating.

Used in a Wide Range of Industries and Applications

Canted coil springs are being used in a diverse group of industries and applications, including oil & gas, renewable energy, aerospace, defense, fluid power, transportation, semiconductor manufacturing, and medical devices

  • As a mechanical connector, canted coil springs are often used to lock together frame assembly of a ventilator cart or to hold components together in wind turbines.
  • As a multiple contact point conductor, canted coil spring assemblies are often used in active implantables such as pacemakers or neurotransmitters. 
  • As EMI/RF shielding, canted coil springs can be found in electrical enclosures or used with data transmission cables.
  • As a part of a spring energized seal, canted coil springs are used in critical aerospace applications and dangerous petrochemical environments involving extreme heat and corrosive materials.

Conclusion

FlexForce canted coil springs can be used as detent mechanisms, EMI/RF shields, multipoint electrical conductors, and energizing springs in seals. They are available in a number of options and can be fully customized to meet user needs. In addition, their reliable performance has already been proven in number industries and applications. If you are interested in FlexForce canted coil springs, contact us at Advanced EMC today.

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

How Canted Coils Springs are Used in Medical Applications

Canted Coil Springs

There are several distinct benefits to be had from using canted coil springs in place of more traditional springs. Because of this, it should come as no surprise that these springs are used extensively in medical applications. 

Canted Coil Springs Are Effective Electrical Connectors and Contacts

Canted coil springs are being used more and more for electrical contacts and connectors. Canted coil connectors make it easier to replace leads and lead segments without harming the patient, and lead interface solutions based on canted coil springs can significantly reduce risk to the patient. In some applications, the procedure time and the patient’s recovery time can be reduced through the wise application of canted coil springs. Canted coil springs also provide high contact power density with a minimal amount of temperature rise. In many instances, they can also reduce the size of the medical device and provide multi-channel connections.

Canted Coil Springs Can Provide EMI and RF Shielding

Another benefit of canted coil springs is their ability to provide shielding from harmful EMI and RFI interference in applications such as ultrasound equipment and vital signs monitors. Many times the medical data being transmitted cannot afford a compromise in its integrity of the disruption of the data flow. Canted coil springs can actually be tuned to meet specific impedance specifications so that medical equipment and devices can be protected from dangerous crosstalk interference.

Canted Coil Springs Can Be Used in Spring-Energized Seals

Canted coil springs can be used in spring-energized seals in medical equipment and external devices as well as implantable devices. Spring-energized seals are often used to maintain a seal when there are problems with hardware gaps, runout, eccentric contact surfaces, and vacuum pressures. In short, spring-energized seals can provide an effective seal where other seals would fail, and when canted coil springs are used then a far more consistent spring force can be applied. 

Canted Coil Springs Serve as Reliable Mechanical Connectors

 

Canted coil springs can provide a reliable connector in three specific ways: 

  • Holding and retaining two parts in alignment with customized forces, often used for surgical instrumentation
  • Securely fastening two parts together while allowing them to still be unlatched (where the latching force can be customized), which is also being used with surgical instrumentation
  • Permanently locking two parts together, including use during orthopedic implant surgery

Unlike most mechanical connector solutions, canted coil springs can achieve these connections with strength, reliability, and incredibly high precision. In addition, when canted coil springs are used as mechanical connectors, there is an option to customize the forces for insertion and breakaway. 

Medical ventilator

Medical Applications of Canted Coil Springs

There are a host of specific medical applications where canted coil springs have proven invaluable. The following is just a sampling:

  • Cochlear implants
  • Implantable medication pumps
  • Insulin delivery systems
  • Orthopedic instruments
  • High-speed surgical power tools
  • Neurostimulators
  • Ultrasound equipment
  • Pain management devices
  • Vital signs monitors
  • Hemodialysis equipment
  • Defibrillators
  • Cardiac rhythm management devices

Conclusion

Canted coil springs are used in connection with everything from neurostimulators to orthopedic implant surgery. Their ability to serve as electrical connectors/contacts, shield from EMI and RF interferences, serve as the energizer in spring-energized seals, and provide tailored mechanical connections make them ideal solutions for many different medical devices and implantables.

 

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Canted Coil Springs: Benefits for Medical Applications

What is a Canted Coil Spring?

Canted coil springs (also known as cant or slant coil springs) are not your typical spring, and this becomes obvious when you take a look at the three different types of tasks they support:

  • Acting as a mechanical connector
  • Energizing seals for better performance
  • Providing EMI/RFI shielding
  • Serving as a multiple contact point conductor

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