Why Canted Coil Springs Provide Constant Force Over a Wide Deflection Range

Canted coil springs deliver near-constant force across a wide deflection range. Learn how their unique geometry, mechanics, and materials outperform traditional springs in demanding applications.

In many mechanical and electromechanical systems, maintaining a stable and predictable force throughout movement is critical. Traditional compression or extension springs often produce a rapidly increasing or decreasing load as they deflect, which can lead to inconsistent performance, excessive wear, or premature failure of mating components. This limitation has driven engineers to seek alternative spring technologies that offer smoother, more controlled force behavior.

Kantige Schraubenfedern have emerged as a preferred solution in applications requiring nearly constant force over a wide deflection range. Their distinctive coil geometry fundamentally changes how load is generated and distributed during compression. As a result, canted coil springs are widely used in electrical connectors, EMI shielding, latching mechanisms, medical devices, aerospace assemblies, and high-cycle industrial systems.

This article explains why canted coil springs provide constant force, focusing on their geometry, mechanical behavior, material characteristics, and real-world performance advantages.


What Are Canted Coil Springs?

Canted coil springs are helical springs made from round or shaped wire, but unlike conventional springs, their coils are intentionally angled—or “canted”—relative to the spring axis.

canted coil springs--handa

Key characteristics of canted coil springs include:

  • Angled coil orientation
  • High flexibility with controlled stiffness
  • Smooth load transfer between coils
  • Ability to function as both mechanical and electrical components

This unique structure is the foundation for the constant-force behavior that distinguishes canted coil springs from traditional designs.


Understanding Force and Deflection in Traditional Springs

To understand why canted coil springs behave differently, it is helpful to first examine how conventional springs generate force.

Compression Springs

In a standard compression spring:

  • Force increases linearly as deflection increases (Hooke’s Law)
  • Spring rate is fixed by wire diameter, coil diameter, and number of active coils
  • Small changes in deflection can result in significant force variation

This behavior is often undesirable in applications requiring gentle contact force or consistent electrical conductivity.

Limitations of Traditional Spring Behavior

Traditional springs often lead to:

  • Overloading at maximum deflection
  • Insufficient force at minimum deflection
  • Sensitivity to tolerance stack-up
  • Uneven wear on mating surfaces

These challenges highlight the need for a spring design capable of maintaining stable force over movement—an area where canted coil springs excel.


The Geometry Behind Constant Force in Canted Coil Springs

The defining feature of canted coil springs is their coil angle, which fundamentally alters how the spring responds to compression.

Angled Coils and Load Distribution

In canted coil springs:

  • Each coil contacts adjacent coils progressively
  • Load is distributed across multiple contact points
  • Coils roll and slide rather than stack directly

This rolling contact reduces the effective spring rate change as deflection increases, allowing force to remain relatively constant.


Coil Engagement Mechanism

Unlike compression springs where coils compress axially, canted coil springs experience a combination of:

  • Bending
  • Torsion
  • Controlled sliding

This multi-mode deformation absorbs deflection without a steep increase in load.


Mechanical Explanation: Why Force Remains Constant

The constant-force behavior of canted coil springs can be explained through several interacting mechanical principles.

1. Progressive Coil Engagement

As the spring is compressed:

  • New coils gradually engage
  • Load is shared rather than concentrated
  • The effective number of active coils changes smoothly

This prevents sudden increases in stiffness.


2. Controlled Friction Between Coils

The angled geometry introduces controlled friction between adjacent coils. This friction:

  • Dampens load spikes
  • Smooths force transmission
  • Enhances stability under vibration

While excessive friction is undesirable in many designs, the controlled friction in canted coil springs is a functional advantage.


3. Reduced Stress Concentration

Because load is distributed along the coil length:

  • Peak stress is lower
  • Fatigue resistance is improved
  • Performance remains consistent over many cycles

This contributes to stable force output throughout the spring’s service life.


Force–Deflection Behavior: Canted Coil vs. Compression Springs

The table below compares typical force-deflection characteristics:

Feder TypForce Change Over DeflectionLoad Stability
Compression SpringRapid, linear increaseLow
Extension SpringRapid increase after preloadLow
Canted Coil FederMinimal change over wide rangeHigh

This comparison explains why canted coil springs are often chosen for precision applications.


Wide Deflection Range: A Key Advantage

One of the most valuable attributes of canted coil springs is their ability to operate over a wide deflection range without loss of function.

Why Wide Deflection Matters

Wide deflection capability allows for:

  • Tolerance compensation
  • Thermal expansion and contraction
  • Misalignment accommodation
  • Long-term wear compensation

Canted coil springs maintain consistent force even as system dimensions change.


Performance Under Repeated Cycling

Canted coil springs are designed for high-cycle applications, often exceeding hundreds of thousands—or even millions—of cycles without significant force degradation.

This makes them ideal for:

  • Connectors with frequent mating cycles
  • Latching and locking mechanisms
  • Dynamic EMI shielding interfaces

Material Selection and Its Impact on Force Consistency

While geometry drives the primary behavior, material selection plays a supporting role in force stability.

Common Materials for Canted Coil Springs

MaterialKey BenefitTypical Applications
Rostfreier StahlKorrosionsbeständigkeitIndustrial, medical
Beryllium-KupferElectrical conductivityElectrical contacts
Elgiloy / MP35NHigh fatigue strengthLuft- und Raumfahrt
Inconel / HastelloyHigh-temperature stabilitySemiconductor equipment

The right material ensures that canted coil springs maintain consistent force under environmental stress.


Role of Manufacturing Precision

Achieving constant force is not only a design challenge but also a manufacturing one.

Critical manufacturing factors include:

  • Precise control of coil angle
  • Consistent wire diameter
  • Uniform heat treatment
  • Accurate ring forming (for closed springs)

High-precision CNC coiling equipment is typically required to produce reliable canted coil springs.


Applications That Benefit from Constant Force

The constant-force behavior of canted coil springs enables performance improvements across many industries.

Electrical and Electronic Applications

  • Stable contact force ensures low and consistent contact resistance
  • Reduces signal loss and intermittent connections
  • Ideal for high-density connectors

EMI / RFI Shielding

In EMI shielding applications:

  • Consistent force maintains continuous electrical grounding
  • Compensates for enclosure tolerances
  • Improves long-term shielding effectiveness

Canted coil springs are often preferred over fingerstock for this reason.


Mechanical Latching and Retention

For latching and locking systems:

  • Constant force provides predictable engagement
  • Reduces wear on mating components
  • Improves user feel and reliability

Design Flexibility Enhances Performance

Another reason canted coil springs provide superior force control is their design flexibility.

Engineers can fine-tune:

  • Coil angle
  • Wire size
  • Free height
  • Ring diameter

This flexibility allows canted coil springs to be optimized for specific force targets without compromising deflection capability.


Summary: Why Canted Coil Springs Excel

The ability of canted coil springs to provide constant force over a wide deflection range is the result of:

  • Angled coil geometry
  • Progressive coil engagement
  • Controlled friction
  • Distributed stress
  • Precision manufacturing

Together, these factors create a spring that behaves predictably, resists fatigue, and adapts to real-world conditions.


Schlussfolgerung

For applications where force stability is critical, schräge Schraubenfedern offer a clear advantage over traditional spring designs. Their unique geometry enables near-constant load across wide deflection ranges, reducing sensitivity to tolerances, wear, and environmental changes.

Whether used in electrical connectors, EMI shielding systems, or mechanical retention assemblies, canted coil springs improve reliability, extend service life, and enhance overall system performance. As engineering demands continue to increase, canted coil springs remain a proven solution for delivering consistent force where it matters most.

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