Overview

A high precision wave spring is a compact compression spring made from a thin, flat metal annulus that is corrugated into a controlled wave pattern, delivering a specified load at a low operating height where a round-wire coil would be too tall. Photochemical etching produces the flat blank and its precise wave geometry from spring-temper stainless or copper alloy sheet without introducing burrs, residual stress or work-hardened edges; the blank is then press-formed to the final crest-to-crest profile. Because the geometry is defined by artwork rather than a die, wave count, crest height and gap are repeatable from the first article to volume production.

Typical high precision wave spring parts run on 0.05-0.60 mm 301/304/316L stainless or beryllium copper, with half-etched bend lines and coined crests that give predictable spring rates in bearing preload, connector and valve assemblies. For very small or high-cycle designs, precision electroforming in nickel offers a stress-free, fine-feature alternative that holds ±0.02 mm on width and gap. The result is a flat, burr-free, dimensionally stable spring that fits tight axial spaces and survives dynamic loading without the distortion a stamped part would carry.

Parameter Window

• Available Materials: 301/304/316L stainless (spring temper), beryllium copper, 17-7PH, electroformed nickel
• Material Thickness Range: 0.05-0.60 mm
• Tolerance: ±0.02 mm on wave width and gap, ±0.01 mm on electroformed parts
• Minimum Feature: 0.10 mm web, half-etched bend line depth to 30% of stock
• Surface Options: stress-relief anneal, passivation, electropolish, deburred edges
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Load & DFM Review - Translate spring rate, free height and solid height into wave count, crest geometry and web width for the chosen temper.
2. Alloy Selection - Choose 301/316L stainless, beryllium copper or electroformed nickel and confirm temper, flatness and grain direction.
3. Cleaning & Lamination - Degrease the strip and laminate dry-film photoresist on both faces for two-sided feature definition.
4. UV Exposure - Image the wave outline and half-etched bend lines from registered high-resolution film.
5. Development - Open the cut regions and inspect narrow webs and crests for resist residue before forming.
6. Controlled Etching - Etch through-cuts and half-etch bend lines in one pass, holding ±0.02 mm on width and gap.
7. Stripping & Forming - Remove resist, stress-relieve, then press-form the flat blank into the final wave profile.
8. Inspection & Packaging - Verify load-deflection, free height and flatness against the approved first article, then tray-pack.

Core Advantages

1. Burr-free, stress-free edges: Chemical removal leaves no stamped burr or work-hardened edge, so cyclic loads do not start cracks at the crest.
2. Low axial height: A wave profile delivers coil-like travel at a fraction of the installed height of a round-wire spring.
3. No hard tooling: A new spring rate is a new film, economical for prototypes and frequent rate revisions.
4. Repeatable spring rate: Artwork-defined wave count and crest height hold ±0.02 mm, so load-deflection stays consistent lot to lot.
5. Half-etched features: Coined crests and bend lines are formed in the same pass without secondary machining.
6. Material flexibility: A high precision wave spring can be etched from stainless, beryllium copper or electroformed to match the load and environment.

Typical Applications

• Bearing preload: Compact axial preload in motors and spindles.
• Electrical connectors: Low-profile contact force in board and circular connectors.
• Valve assemblies: Controlled return force in hydraulic and pneumatic valves.
• Medical devices: Small, clean springs for surgical and diagnostic tools.
• Optical mounts: Gentle, repeatable clamping of lenses and sensors.
• Aerospace mechanisms: Lightweight preload in actuators and latches.

Design Notes & Process Considerations

1. Load versus thickness: State spring rate, free height and solid height so wave count and crest geometry can be derived.
2. Web width: Keep the narrowest web at or above 1.2 times material thickness to avoid lifting during etch and forming.
3. Half-etch depth: Specify bend-line depth as a percentage of stock, since it controls forming force and fatigue life.
4. Grain direction: Align wave crests with the rolling direction where the design allows, improving fatigue resistance.
5. Flatness after forming: Call out post-form flatness and free height, as forming and stress relief both move dimensions.
6. Panelization: Nest multiple spring blanks on one sheet with shared registration marks to cut cost on repeat lots.