Photochemical etching (also known as photo etching or chemical milling) is a subtractive metal manufacturing service that creates intricate precision metal components from thin metal sheets. This non-contact machining process uses photoresist and chemical etchants to selectively remove unwanted metal material, delivering complex geometries that are difficult or uneconomical to produce via stamping, laser cutting or CNC machining.

How Photochemical Etching Works

Artwork & Tooling Preparation: Convert customer CAD drawings into film phototool. No expensive hard metal molds required.

Metal Sheet Cleaning: Degrease and clean raw metal stock to ensure photoresist adheres firmly.

Photoresist Lamination: Coat both sides of the metal sheet with UV-sensitive photoresist film.

UV Exposure: Align the phototool over the coated metal and expose under UV light, hardening the resist on the design areas.

Developing: Wash away unexposed photoresist, exposing the metal regions that need to be etched away.

Chemical Etching: Immerse the sheet in etchant solution to dissolve exposed metal, etching through or partially into the material.

Stripping: Remove the remaining hardened photoresist to reveal the finished metal parts.

Inspection & Finishing: Carry out dimensional inspection, deburr, surface treatment or plating per customer requirements.

Core Advantages of Photochemical Etching Services

Zero hard tooling cost: Only low-cost phototool films are needed. Fast design revisions without high mold modification fees, perfect for prototypes and low-to-medium volume runs.

Burr-free & stress-free parts: No mechanical force applied during etching. Parts retain original material properties with no deformation, micro-cracks or burrs.

Ultra-fine intricate geometries: Produce tiny holes, sharp corners, complex patterns, thin slots and nested multi-part layouts with tight tolerances. Feature sizes can be close to the metal sheet thickness.

Wide material compatibility: Works on stainless steel, copper, nickel, nitinol, kovar, molybdenum, brass and many other thin metal alloys.

Fast lead time: Prototypes can be finished within days, much quicker than traditional stamping tooling development.

Typical Application Fields

Semiconductor packaging: SMT stencils, shadow masks, lead frames, FCBGA ball placement stencils

Electronics: EMI/RFI shielding cans, shielding gaskets, precision spring contacts

Energy & New Energy: Fuel cell bipolar plates, vapor chamber structures, filter meshes

Medical: Nitinol surgical components, precision filters, medical grade thin metal shims

Aerospace & Instrumentation: Encoder discs, metal shims, washers, spacers

Consumer Audio: Custom speaker grilles, decorative etched nameplates and labels

Design Considerations

Material thickness: Most suitable for thin metal sheets typically 0.01mm ~ 1.5mm.

Minimum feature rule: The smallest slot or hole width should generally not be less than the material thickness.

Tolerance: Dimensional tolerance depends on sheet thickness and part size, we will confirm specifications during DFM review.

Material selection: Different metals require matched etchant chemistry, affecting etching rate and surface finish.

Secondary processes: Plating, passivation, polishing and heat treatment can be added as post-processing options.