Precision etching, commonly known as photochemical etching, is a subtractive micro manufacturing technology that selectively removes material from thin metal sheets through controlled chemical reaction. Unlike traditional mechanical cutting, this non-contact process avoids shear force and thermal damage, maintaining the base material’s original metallurgical properties. It excels at producing intricate micro geometries, fine slits, dense hole arrays and ultra-thin flat components with tight dimensional tolerances.

A wide range of metals are available: 304/316 stainless steel, copper, brass, beryllium copper, Kovar, Invar, titanium, molybdenum, nickel alloys and spring steel. Usable thickness ranges from 0.02 mm up to 2.0 mm. The process supports both through-etching for full cutout profiles and blind half-etching for controlled-depth grooves, bend lines and recessed features.

Step-by-Step Precision Etching Workflow

1. DFM & Precision Artwork CompensationEngineers analyze drawing tolerances, micro feature sizes, hole pitch and aspect ratios. Side undercut compensation is calculated for each material to guarantee final dimensional accuracy. Optimize nesting layout to improve material utilization while keeping feature consistency across the whole panel.
2. High-Level Surface Pre-treatmentMetal sheets undergo strict alkaline degreasing, pickling and multi-stage DI water rinsing to eliminate oil, fingerprints and surface oxides. Consistent surface activity is critical to prevent uneven etching and micro pattern defects.
3. Dry Film Photoresist LaminationHigh-resolution dry film is laminated on single or double sides under stable heat and pressure, forming a uniform, defect-free protective mask for micro features.
4. High-Precision UV Exposure & DevelopmentUV exposure transfers micro patterns onto photoresist via high-resolution photomask. Developer washes away resist on areas to be etched, exposing bare metal for chemical removal.
5. Controlled Precision Chemical Etching (Core Step)The sheet passes through a spray etching chamber. Etchant concentration, temperature, spray pressure and conveyor speed are precisely stabilized. Double-sided etching ensures uniform material removal for micro holes and fine structures.
6. Resist Stripping & Ultra-Clean RinsingStrip the photoresist mask, followed by multi-cycle deionized water rinsing and drying to eliminate residual chemicals and avoid surface staining or corrosion.
7. Precision Metrology InspectionInspect dimensions, hole pitch, edge roughness, flatness and etch depth. Apply optical microscopy and coordinate measuring machines for micro features and tight tolerance verification.
8. Optional Secondary Post-processingElectropolishing, passivation, plating, flattening, laser marking, bending, forming and component assembly for finished precision parts.

Core Advantages of Precision Etching

1. Burr-free & zero residual stressNo mechanical punching or thermal cutting. Parts remain flat without burrs, edge rollover or internal stress, which is essential for stacked shims and micro assemblies.
2. Micro feature capabilityCapable of ultra-fine patterns, dense micro-hole arrays and narrow slits that are difficult or impossible to achieve by stamping, laser cutting or CNC machining.
3. Tight & repeatable tolerancesStable dimensional consistency across the entire sheet and batch. Ideal for mass production of precision components with strict tolerance requirements.
4. No hard tooling, fast prototypingOnly digital artwork and photomask are required. Design revisions can be completed quickly with low cost, greatly shortening R&D verification cycles.
5. Broad material compatibilityWorks on most thin metallic materials including stainless steel, refractory metals, special alloys and spring materials.
6. Cost-efficient for custom low & medium volumeEliminates expensive die investment. Perfect for custom R&D samples and small-batch precision parts.

Typical Applications

• Semiconductor & electronics: lead frames, encoder discs, EMI shielding parts, test contact springs, micro masks
• Medical: surgical components, microfluidic plates, filter meshes, diagnostic instrument parts
• Aerospace: precision shims, thermal shielding components, RF micro parts
• Industrial: micro sieves, precision filter meshes, etched nameplates, alignment spacers
• New energy: fuel cell bipolar plates, vapor chamber micro channels, battery electrode meshes

Design Limitations & Notes

Precision wet etching is isotropic, so lateral undercut must be compensated during CAD design. Minimum feature width is generally limited by sheet thickness. For features deeper than 2 mm or complex 3D structures, EDM, CNC or stamping may be more suitable. Brittle materials require careful DFM review to avoid cracking during handling.