Chemical etching (photochemical machining) is a high-precision subtractive manufacturing process for thin metal precision spring plates. Unlike stamping, etching forms spring profiles without heavy mechanical impact. It retains the base material’s inherent elastic properties, eliminating edge burrs and residual forming stress that may cause spring fatigue or early failure.

Process Flow

1. Material preparation: Select spring-grade metal foils such as stainless steel (301, 316), beryllium copper, phosphor bronze, nickel alloy.
2. Surface pre-cleaning: Remove grease and oxide layers to guarantee good photoresist adhesion.
3. Dry film lamination: Laminate photoresist film on both sides of the metal sheet.
4. UV exposure & development: Transfer custom spring plate geometry by UV exposure; wash away unexposed resist to expose the metal regions for etching.
5. Chemical etching: Controlled etchant spray selectively removes unwanted metal to form spring contours, cantilever beams, slots and mounting holes.
6. Photoresist stripping: Strip the protective photoresist after etching.
7. Post-treatment: Cleaning, passivation, heat tempering or surface plating as required to tune spring elasticity and corrosion resistance.
8. Quality inspection: Dimensional check, flatness test, elastic fatigue test and surface quality verification.

Core Advantages

• Burr-free edges, no secondary deburring that may damage spring performance.
• Low residual stress, preserving original material elasticity.
• Complex fine features: cantilever springs, small slots and cutouts can be fabricated in one step.
• Supports ultra-thin spring materials starting from 0.02mm.
• No hard tooling required, fast prototyping and low cost for design iterations.
• Consistent part-to-part accuracy for mass production.
• Custom pattern nesting available to optimize material utilization.

Application Fields

• Electronic connector spring contacts
• Micro switches and tactile sensors
• Battery contact spring plates for consumer electronics
• Medical device micro spring components
• Automotive sensor and relay spring parts

Design Notes

• Choose proper spring alloy: beryllium copper for high conductivity, 301 stainless steel for strong elasticity.
• Keep smooth transition radii at beam root to reduce stress concentration and extend fatigue life.
• Avoid overly narrow fragile features that may break under repeated deflection.
• Spring performance is affected by material thickness; confirm bending requirements at design stage.
• Heat treatment or plating after etching should be evaluated to avoid altering elastic properties.