Overview

An etched stainless steel spring is a finished, functional elastic component — a flat spiral, cantilever blade, latch arm, constant-force strip or EMI finger — produced by photochemical machining from spring-temper stainless foil. Because the metal is dissolved rather than sheared, the part arrives flat, burr-free and free of a work-hardened bend root, which is why its measured force matches the design intent instead of drifting with die wear. Buyers specify these springs in 301, 304, 316L or 17-7PH from 0.05 mm to 0.60 mm, usually with a force band rather than a single target value.

The practical concern with an etched stainless steel spring is verification of the finished part, not the chemistry. A supplier should deliver a force-deflection curve measured on the formed and plated component, a fatigue result at the agreed deflection, flatness data and a surface-finish record, since all four change during forming, passivation and plating. Packaging also matters: thin, high-force arms nest and tangle easily, so tray or liner packing and a clear orientation mark protect the free height through shipping and automated placement. Those deliverables are what turn a well-etched blank into a spring that drops into an assembly without adjustment.

Parameter Window

• Available Materials: stainless steel 301/304/316L spring temper, 17-7PH, 430
• Material Thickness Range: 0.05–0.60 mm
• Tolerance: ±0.02 mm on profile, ±10% on force band, ±0.05 mm on free height
• Minimum Feature: 0.10 mm line, 0.15 mm slot at 0.20 mm stock
• Surface Options: passivation, electropolish, formed and pre-loaded, anodised-free marking, tray or liner packing
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Functional Specification — Agree force band, deflection, cycle life, envelope, mating part and assembly method.
2. Spring Form Selection — Choose spiral, cantilever, latch or finger geometry and simulate the load case.
3. Material & Temper Lock — Reserve alloy, temper and rolling direction so later lots match the qualified sample.
4. Cleaning & Lamination — Degrease and laminate dry-film resist on both faces under controlled heat and pressure.
5. Exposure & Development — Expose through registered film, develop, and inspect narrow arms for residue.
6. Etching & Half-Etching — Cut the outline while timing reduced-depth flexure zones in the same controlled bath.
7. Forming & Finishing — Strip, passivate or electropolish, then form to free height and stress-relieve.
8. Finished-Part Verification — Measure force-deflection, fatigue, flatness and free height, then tray-pack with orientation.

Core Advantages

1. Ready-to-assemble flatness: Burr-free blanks seat on the mating face without secondary deburring or shimming.
2. Predictable force band: Whole-sheet etching plus controlled forming keeps measured force inside the agreed window.
3. Complex finished shapes: Spirals, fingers and asymmetric arms are produced as one piece, not welded assemblies.
4. Stable fatigue behaviour: No sheared edge or hardened bend root to initiate early cracking.
5. Traceable finishing: Passivation, electropolish and forming records accompany each lot for audit.
6. Protected delivery: A qualified etched stainless steel spring ships in trays or on liners with orientation marks, so free height survives transit.

Typical Applications

• Flat spiral and clock springs: Compact rotational return elements in retractors and mechanisms.
• Cantilever switch blades: Snap-action flexures for micro switches and relay contacts.
• Latch and retention arms: Springs that hold a cover, module or connector without a separate clip.
• EMI shielding fingers: Grounding contacts along enclosure seams that tolerate repeated opening.
• Constant-force strips: Long, low-force springs for counterbalances and cable retractors.
• Medical and instrument clips: Passivated, burr-free springs for small disposable mechanisms.

Design Notes & Process Considerations

1. Slot width versus thickness: Keep narrow slots at 1.5 × stock thickness or wider to avoid warped walls.
2. Force band, not a point: State acceptable minimum and maximum force at a defined deflection, not a single number.
3. Free height after forming: Define free height and its tolerance on the formed part, since flat-foil dimensions do not predict it.
4. Fatigue test conditions: Specify cycle count, deflection amplitude and allowable force loss after cycling.
5. Finishing effects: Passivation and electropolish remove material; re-verify force after finishing, not before.
6. Incoming inspection plan: Define sampling, test fixture and acceptance records; a controlled etched stainless steel spring programme ships with force and flatness data the buyer can re-measure on receipt.