Overview

An etched titanium leaf spring is a flat, compliant part cut from commercially pure titanium or Ti-6Al-4V foil by photochemical machining, chosen where weight, corrosion resistance and non-magnetic behaviour matter more than raw stiffness. Titanium's elastic modulus is roughly half that of steel, so a spring of the same geometry deflects further at a given load, while its passive oxide gives long life in chloride, bodily fluid and marine environments. Stock is typically Grade 1, Grade 2 or Grade 5 between 0.05 mm and 0.50 mm, with profile tolerance held to ±0.02 mm.

Producing an etched titanium leaf spring is chemically more demanding than etching stainless. The TiO2 passive film resists most etchants, so fluoride-bearing chemistry, careful activation and tightly controlled temperature are needed to get a uniform cut; the same bath can also drive hydrogen into the metal, which embrittles a flexure that must cycle for years. Qualified lines therefore combine validated etchant windows with vacuum degassing or controlled stress-relief, and verify hydrogen content alongside force-deflection behaviour. The result is a burr-free, stress-free spring that can be anodised for colour coding or left passivated for implantable and aerospace use.

Parameter Window

• Available Materials: titanium Grade 1/Grade 2 commercially pure, Ti-6Al-4V (Grade 5), beta-titanium alloys
• Material Thickness Range: 0.05–0.50 mm
• Tolerance: ±0.02 mm on profile, ±10% of thickness on half-etched depth
• Minimum Feature: 0.10 mm line width, 0.15 mm slot at 0.15 mm stock
• Surface Options: passivation, anodised colour coding, electropolish, vacuum degassing, formed and pre-loaded
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Service Environment Review — Define medium, temperature, deflection, cycle life and whether the part is implantable.
2. Grade Selection — Choose CP Grade 1/2 for formability or Grade 5 for strength, and lock the foil heat.
3. Artwork Compensation — Apply a titanium-specific etch factor to the outline, slots and half-etch boundaries.
4. Cleaning & Activation — Remove the passive oxide in a controlled fluoride pre-dip, then laminate dry-film resist.
5. Exposure & Development — Expose through registered film and develop, inspecting narrow flexures for residue.
6. Controlled Etching — Spray fluoride chemistry under logged temperature and time to limit hydrogen pickup.
7. Stripping & Degassing — Strip resist, then vacuum degas or stress-relieve to bring hydrogen back within spec.
8. Verification & Packing — Check force-deflection, flatness, hydrogen content and surface finish, then pack in clean trays.

Core Advantages

1. High specific strength: Titanium gives more deflection per gram than a stainless spring of the same outline.
2. Corrosion immunity: The passive oxide survives chloride, bodily fluid and marine exposure without plating.
3. Non-magnetic and biocompatible: Suitable for MRI-adjacent hardware and implantable mechanisms.
4. Burr-free flexures: Chemical cutting leaves no sheared edge to initiate a fatigue crack at the bend root.
5. Colour-coded anodising: Anodic films identify force ratings or sizes without paint or ink that could shed.
6. Controlled hydrogen: A qualified etched titanium leaf spring is degassed and lot-tested, so embrittlement does not appear in service.

Typical Applications

• Implantable device clips: Passivated springs for surgical tools and long-term implant mechanisms.
• Aerospace latch springs: Lightweight, non-magnetic flexures for access panels and connectors.
• Marine and chemical sensors: Springs exposed to salt spray or aggressive media without protective coating.
• MRI and laboratory fixtures: Non-magnetic compliant parts for imaging and analytical equipment.
• Battery and fuel-cell contacts: Corrosion-resistant springs in humid, electrochemically active assemblies.
• Precision optical mounts: Low-hysteresis flexures for lens and mirror adjustment stages.

Design Notes & Process Considerations

1. Modulus-based sizing: Because titanium is about half as stiff as steel, recalculate thickness and arm length rather than copying a steel design.
2. Slot width versus thickness: Keep narrow slots at 1.5 × stock thickness or wider to resist distortion during etching.
3. Hydrogen limit: State a maximum hydrogen content and require a degassing record with each lot.
4. Etchant and activation control: Fluoride chemistry attacks the passive film unevenly if temperature drifts; lock the window at qualification.
5. Half-etch depth: Call out residual thickness at the flexure, since force scales roughly with the cube of thickness.
6. Surface specification: Define passivation or anodising colour and the cleanliness level; a well-controlled etched titanium leaf spring should arrive free of embedded abrasive and fluoride residue.