Canted Coil Spring for EMI Shielding

Canted coil spring for EMI shielding provide consistent contact force, superior conductivity, and long service life. Learn how they work, key advantages over fingerstock, material options, installation design, and typical EMI shielding applications.

Canted Coil Spring for EMI Shielding

Electromagnetic interference (EMI) has become a critical challenge in modern electronic systems. As operating frequencies increase and devices become smaller, reliable EMI shielding solutions are essential to ensure signal integrity, regulatory compliance, and long-term product performance. Among various shielding technologies, the canted coil spring for EMI shielding stands out as a high-performance, durable, and design-flexible solution.

Unlike traditional fingerstock or foam-based gaskets, canted coil springs offer constant contact force, excellent electrical conductivity, and outstanding mechanical resilience, making them ideal for demanding environments and high-cycle applications.

This article provides a comprehensive overview of canted coil springs for EMI shielding, explaining how they work, their advantages, material options, installation considerations, and common applications.

What Is a Canted Coil Spring?

A Schrägzugfeder—also known as a slant coil spring, wire wound spring, or slanted coil spring—is a precision-engineered spring made by winding round or flat wire into coils that are intentionally angled (canted) rather than perpendicular to the spring axis.

This unique geometry allows the spring to compress with a flat load-deflection curve, meaning it delivers nearly constant force across a wide range of deflection. Unlike traditional compression springs that increase force rapidly as they compress, a canted coil spring maintains predictable and stable contact pressure.

Originally developed as an energizer for seals such as U-cups, canted coil springs are now widely used in EMI shielding applications, where consistent electrical contact is crucial.

How It Works in EMI Shielding

In EMI shielding, the primary goal is to create a continuous, low-resistance electrical path between mating surfaces—typically between an enclosure and a cover or between two conductive housings.

When used as an EMI shielding element, a canted coil spring:

• Is installed in a machined groove or channel
• Compresses when two conductive surfaces come together
• Maintains constant contact force even with tolerance variations
• Ensures reliable electrical grounding and shielding effectiveness

Because of its angled coil structure, the spring can absorb dimensional variations, thermal expansion, vibration, and repeated opening/closing cycles without losing contact force.

The result is stable EMI shielding performance across the product’s entire service life, even in harsh or high-cycle environments.

Advantages Over Fingerstock

Traditional EMI fingerstock gaskets are widely used, but they have inherent limitations. Canted coil springs offer several key advantages:

1. Constant Force Over Wide Deflection

Fingerstock typically exhibits increasing force with compression, which can cause assembly issues or excessive wear. Canted coil springs maintain nearly constant force, reducing stress on mating components.

2. Superior Durability and Cycle Life

Canted coil springs are designed for millions of compression cycles, making them ideal for applications requiring frequent engagement and disengagement, such as access panels or modular enclosures.

3. Improved Contact Reliability

The continuous spring geometry provides mehrere Kontaktstellen, ensuring consistent conductivity even if minor contamination or surface irregularities exist.

4. Better Tolerance Compensation

Canted coil springs easily accommodate misalignment, flatness variation, and thermal expansion, where fingerstock may permanently deform or lose effectiveness.

5. Lower and Controlled Mating Force

Because the force remains stable, designers can achieve effective EMI shielding while maintaining low insertion and breakout forces, especially important in handheld or serviceable equipment.

Typische Anwendungen

Canted coil springs for EMI shielding are used across a wide range of industries where reliability, performance, and longevity are critical:

• RF and microwave enclosures
• Telecom base stations and networking equipment
• Aerospace and defense electronics
• Medical diagnostic and imaging devices
• Industrial control cabinets
• Automotive electronics and EV systems
• Semiconductor manufacturing equipment
• Ruggedized outdoor or marine electronics

They are particularly suitable for high-speed rotary systems, sliding interfaces, and applications requiring tight control of friction and consistent grounding.

Material-Optionen

Material selection plays a crucial role in EMI shielding effectiveness, corrosion resistance, and mechanical life. Common material options include:

Beryllium-Kupfer (BeCu)

• Ausgezeichnete elektrische Leitfähigkeit
• Outstanding spring memory and fatigue resistance
• Ideal for high-performance EMI shielding
• Commonly plated for enhanced corrosion resistance

Rostfreier Stahl

• Good mechanical strength
• Suitable for harsh or corrosive environments
• Often used where conductivity requirements are moderate

Beschichtungsoptionen

To enhance performance, canted coil springs can be plated with:

• Tin (Sn) for improved conductivity and solderability
• Silver (Ag) for low contact resistance
• Gold (Au) for high-reliability, low-signal applications

Custom materials and plating combinations are available to meet specific environmental and electrical requirements.

Installation & Groove Design

Proper installation and groove design are essential for optimal EMI shielding performance.

Groove Design Considerations

• Groove width and depth must allow sufficient compression
• Avoid sharp edges that could damage the spring
• Ensure conductive surfaces are clean and properly finished

Compression Recommendations

• Typical working compression ranges from 10% to 30%
• Over-compression can reduce cycle life
• Under-compression may lead to insufficient contact force

Installationsmethoden

Canted coil springs can be:

• Installed as continuous rings
• Supplied as linear lengths
• Customized to fit complex geometries

Their design flexibility allows easy integration into both new designs and retrofit applications.

Product Description

Canted Coil Spring for EMI Shielding
Our canted coil springs are precision-manufactured to provide reliable EMI shielding performance in demanding applications. Featuring a slanted coil geometry, these springs deliver constant contact force over a wide deflection range, ensuring stable electrical conductivity even under vibration, thermal cycling, and repeated use.

Available in custom sizes, materials, and plating options, they are ideal for use as EMI shielding gaskets, grounding elements, and conductive contacts in high-reliability electronic systems.

FAQs

Q1: What makes canted coil springs suitable for EMI shielding?
Their constant force, multiple contact points, and excellent conductivity make them ideal for maintaining reliable electrical grounding.

Q2: How do canted coil springs compare to fingerstock gaskets?
They offer longer service life, better tolerance compensation, and more consistent contact force.

Q3: Can canted coil springs be customized?
Yes. Custom diameters, wire sizes, materials, and plating options are available.

Q4: Are they suitable for high-cycle applications?
Absolutely. Canted coil springs are designed for millions of compression cycles.

Q5: What industries commonly use them?
Telecommunications, aerospace, medical devices, industrial electronics, automotive, and semiconductor equipment.

For more info.,please email to: sale01@handashielding.com