Overview

An etched titanium spring is a photochemically machined flexure, cantilever or contact spring produced from thin titanium sheet, where a burr-free beam and a controlled spring rate matter more than bulk strength. A photoresist mask is exposed from film, developed, and the unprotected metal is dissolved so beam widths, slots and gaps are formed in one pass without the roll-over or residual stress a punch leaves. Ti-6Al-4V (Gr.5), CP titanium Gr.2 and nickel-titanium shape-memory alloy are the usual substrates, run at 0.05–0.8 mm, with beam widths down to 0.10 mm and gaps to 0.15 mm.

For medical, aerospace and connector buyers, an etched titanium spring removes three constraints: stamped flexures carry edge burrs that become fatigue starts, wire forms cannot hold a flat, planar geometry, and laser cutting leaves a heat-affected rim that changes the temper. Photochemical etching holds beam width and gap from a film, so the first sample and the volume lot share the same spring rate, and one sheet can combine cantilevers, contact pads and half-etched bend lines. Stress-relief anneal and surface finishing follow to stabilize the flexural behavior.

Parameter Window

• Available Materials: Ti-6Al-4V (Gr.5), CP titanium Gr.2, NiTi shape-memory alloy, with 301 stainless steel as an alternative
• Material Thickness Range: 0.05–0.8 mm
• Tolerance: ±0.02 mm on beam width, ±0.03 mm on outer profile
• Minimum Feature: 0.10 mm cantilever beam, 0.15 mm gap
• Surface Options: bead blast, acid pickling, anodizing, stress-relief anneal, burr-free finish, electropolishing
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & Spring-Rate Review — Convert the flexure layout to vector artwork and check beam width, gap and bend line against thickness.
2. Material Selection — Match Ti-6Al-4V, CP Ti or NiTi temper to the required spring rate, fatigue life and temperature range.
3. Cleaning & Lamination — Degrease the sheet and laminate dry-film resist on both faces without stressing narrow beams.
4. UV Exposure — Expose through high-resolution film with the beam axis registered to the sheet edge for consistent geometry.
5. Development — Wash out unexposed resist to open the slots and gaps, then inspect for under-developed beam roots.
6. Etching — Spray a titanium-compatible etchant with tight time control to hold straight, burr-free beam edges.
7. Stripping & Finishing — Remove resist, neutralize, then stress-relief anneal, bead blast, pickle or anodize as specified.
8. Inspection & Packaging — Measure beam width, gap, flatness and spring rate against the approved sample, then pack in trays.

Core Advantages

1. Burr-free beams: Chemical removal leaves no edge burr, so fatigue cracks have nowhere to start.
2. No hard tooling: A new flexure layout is a new film, keeping prototype springs and frequent revisions economical.
3. Repeatable spring rate: Beam width holds to ±0.02 mm, so stiffness matches from the first article to volume production.
4. Flat, planar geometry: No mechanical force is applied, so complex planar springs stay flat and seat evenly.
5. Complex flexures in one pass: Cantilevers, contact pads and half-etched bend lines form together without extra setups.
6. Light and corrosion-resistant: Titanium lets the etched titanium spring serve implanted, airborne and humid environments.

Typical Applications

• Medical device flexures: Biocompatible cantilevers for surgical tools and implantable mechanisms.
• Connector and probe contacts: Flat spring contacts that hold force over many mating cycles.
• Aerospace latch and clip springs: Lightweight, corrosion-resistant flexures for cabin and control hardware.
• Valve and diaphragm springs: Thin planar springs for precision fluid-control assemblies.
• Wearable and optical mechanisms: Compact flexures for hinges, shutters and adjustment stages.
• Sensor and switch springs: Calibrated beams that set a repeatable actuation force.

Design Notes & Process Considerations

1. Beam-to-thickness ratio: Keep the narrowest beam at 1.2 × material thickness, or taper will thin it and shift the spring rate.
2. Gap width: Hold the minimum gap at 0.15 mm or 1 × thickness, whichever is larger, to avoid etch bridging.
3. Spring-rate callout: State target force at a defined deflection, not just beam width, so stiffness can be verified.
4. Half-etch bend lines: Declare residual thickness at bend lines, since it controls where the flexure actually bends.
5. Stress-relief anneal: Specify anneal and flatness, because residual stress otherwise drifts the free position over time.
6. Handling and burr: Require protective trays and burr-free edges, since thin flexures bend easily and a kink changes the force.