What Is a Spring? Its Types and Manufacturing Process
A spring is a mechanical component that stores energy and releases it to provide a stable, continuous force. Depending on its design, a spring can extend, compress, twist, or rotate to support the movement of a device
Springs are essential in countless machines and everyday equipment – such as automobiles, lifting systems, medical beds, furniture hardware, and industrial automation. In these applications, the spring is not an accessory; it is a core functional element that keeps mechanisms moving smoothly and safely.
Types of Springs
Springs come in many forms, each with its own structure and function. Their performance depends heavily on the spring material and the manufacturing method used.
Wire-based springs
Wire-based springs are usually made from steel spring wires. Wires for springs are drawn to precise diameters and hardened for elasticity. Common wire-based spring types include:
- Compression springs– resist compression; used in shock absorbers and mechanical switches.
- Extension springs– stretch under load; used in automotive components and machinery levers.
- Torsion springs– apply twisting force; used in hinges, clips, and door mechanisms.
Strip-based flat spiral springs
Strip-based flat spiral springs are usually made from high-carbon steel strips or stainless steel strips, including:
- Power springs– store torque when wound and release it gradually to generate smooth rotary motion. Common in seat-belt retractors, timers, toys, and hose reels.
- Constant force springs– deliver nearly uniform pulling force across the entire stroke. Ideal for retractable cords, height-adjustable mechanisms, and linear motion devices.
- Constant torque springs– provide stable rotational torque while winding and unwinding. Used in cable reels, motor return systems, and controlled–rotation mechanisms.
- Prestressed power springs– wound under internal pre-stress to store more energy and offer more working turns than standard power springs. Common in fall arresters, heavy-duty hose retractors, and automotive safety systems.
- Variable force springs– deliver a force that changes with extension – typically light at the beginning and stronger as it extends. Used in retail display pushers, product feeders, and POP merchandising systems.
How Springs Are Made
To ensure structural stability, fatigue resistance, accuracy, and long service life, spring manufacturing undergoes several key stages:
Cold Coiling / Cold Forming
Most springs are shaped at room temperature to preserve the material’s hardness and elasticity.
- Wire springs are cold-coiled into helical shaped using mechanical or CNC coiling machines.
- Flat spiral springs are cold-wound around an arbor to form a tight spiral.
Their ends may be shaped into tabs, holes, or hooks depending on the design. This step requires strict control of coil spacing, curvature, number of turns, and overall dimensions to ensure consistent force output.
Heat Treatment (Tempering)
After cold forming, springs undergo tempering to relieve internal stress. This improves:
- toughness
- elasticity stability
- fatigue resistance
Without tempering, springs may deform permanently or break under repeated use.
Surface Protection - Zinc Plating
A zinc coating is applied to protect the spring from corrosion, especially when exposed to air, humidity, or industrial environments.
Anti-Rust Coating or Oil Treatment
A final anti-rust layer or protective oil is added to strengthen corrosion resistance. This is especially important for springs used in:
- outdoor applications
- high-humidity environments
- long-term storage
Partner with Teng Yao for Flat Strip Spring Solutions
As a specialist in flat spiral spring manufacturing, Teng Yao offers durable materials, accurate force tuning, and fully customizable designs to match your application.
If you’re designing a new mechanism or improving an existing one, contact us to explore tailored flat strip spring solutions for your project.