Springs

Spring forming coils wire into precise elastic components for force, motion control, and energy storage across compression, extension, and torsion applications at scalable volumes.

Overview

Spring manufacturing forms round wire into helical shapes to create compression, extension, and torsion springs with defined force–deflection behavior. Coiling, heat treatment, and finishing steps control free length, spring rate, solid height, and fatigue life. Shops can handle a wide range of wire diameters, from fine instrument springs to heavy-duty industrial parts, in carbon steel, stainless, and specialty alloys.

Choose springs when you need repeatable force, motion control, or energy storage in a compact package. They work well from prototypes through high-volume production, and they integrate easily with turned, stamped, or molded components. Tradeoffs include limits on extreme miniaturization, very tight tolerances on rate or load without cost increases, and geometry constraints set by coiling tooling and wire diameter. Very high temperature, highly corrosive, or ultra-high-cycle applications may require premium alloys and careful fatigue design, which increase cost but significantly improve reliability.

Common Materials

  • Music wire (ASTM A228)
  • Stainless steel 302
  • Stainless steel 17-7PH
  • Phosphor bronze
  • Beryllium copper
  • Inconel X-750

Tolerances

±0.005" on key diameters and free length; ±2–10% on spring rate and load at height, depending on size and material

Applications

  • Compression springs in valves and actuators
  • Torsion springs in hinges, clips, and latches
  • Extension springs in garage doors and counterbalances
  • Battery contacts and electrical spring contacts
  • Return springs in switches and pushbuttons
  • Vibration isolation and suspension springs

When to Choose Springs

Use springs when you need predictable force or torque over a deflection range using coiled wire, in a compact, repeatable, and easily assembled form. They suit anything from prototype runs to very high volumes, especially where adjustment, preload, or compliance is needed in the mechanism. They are ideal when standard wire sizes and helical geometries can achieve your force, travel, and life requirements without excessive complexity.

vs CNC machining

Choose springs over machined flexures or compliant features when you need larger travel, higher energy storage, or lower part cost at volume. Coiled springs also simplify tuning force by adjusting wire diameter, coil count, or free length instead of re-machining solid parts.

vs Stamping

Use coiled springs instead of stamped flat springs when your design needs long stroke, round-wire contact surfaces, or multi-directional deflection with minimal stress concentration. Stamped springs fit best for flat geometries and very high volume; coils are more flexible for tuning and packaging in cylindrical spaces.

vs 3D printing

Select conventional spring forming over 3D-printed springs when you need reliable fatigue life, known material properties, and low cost per part. Printed springs are useful for complex prototypes, but coiled wire springs deliver far better durability and price for production loads and cycles.

vs Plastic injection molding

Prefer metal springs over molded plastic springs when you need high cycle life, stable spring rate over temperature, or high stress capability in compact geometries. Plastic springs work for low loads and corrosive environments, but metal coils handle higher forces and more demanding fatigue requirements.

vs Gas springs

Choose wire springs instead of gas springs when you want simple, maintenance-free force elements without seals, pressure loss risk, or orientation constraints. Wire springs suit smaller strokes and lower forces with tight packaging, while gas springs fit large strokes and near-constant force profiles.

Design Considerations

  • Specify operating loads and deflections (min, nominal, max) rather than just spring rate so the shop can optimize coil count, wire size, and free length
  • Use standard wire diameters and materials wherever possible to reduce lead time and setup costs
  • Avoid extremely tight coils (low index) and sharp bends near hooks or legs; they drive up stress and scrap rates
  • Keep dimensional tolerances realistic, especially on free length and solid height; request tighter spring rate only where functionally critical
  • Clearly define environment, temperature range, and expected cycle life so the right alloy, finish, and heat treatment can be selected
  • Standardize end types (closed and ground, closed only, open, specific hooks) and provide clear assembly constraints to prevent interference at solid height