Photo etching on metal, also known as photochemical machining (PCM), is an advanced precision cold manufacturing process used to produce complex, ultra-thin, and high-tolerance metal components. Unlike laser cutting, stamping, or CNC milling that rely on heat or mechanical force, metal photo etching removes unwanted material through controlled chemical reactions combined with photolithography technology. This unique manufacturing method delivers burr-free, stress-free, and distortion-free metal parts that cannot be easily achieved by traditional machining methods, making it widely adopted in electronics, medical devices, aerospace, new energy and precision instrumentation industries.

The fundamental principle of photo etching on metal is selective material removal. The entire process starts by transferring digital CAD designs onto flat metal surfaces using UV-sensitive photoresist film. After precise UV exposure and developing, the reserved pattern areas form a durable chemical-resistant mask, while the exposed metal areas are dissolved by professional etching solutions at the molecular level. Since the whole procedure runs at room temperature without thermal impact or mechanical pressure, the original metal properties including elasticity, conductivity, flatness and corrosion resistance remain completely unchanged.

The industrial photo etching workflow follows a strict seven-step standardized procedure. First, metal sheets go through thorough pre-treatment including degreasing, oxide removal, surface micro-etching and full drying. This step ensures clean and activated metal surfaces to guarantee stable photoresist adhesion, preventing common defects such as pattern peeling, pinholes and uneven etching depth.

Second, photoresist dry film is laminated on both sides of the metal plate. Dry film lamination is the mainstream solution for stainless steel and copper alloy plates, while ultra-thin metal foils use liquid photoresist coating to avoid deformation. The film must be tightly attached without bubbles or gaps to ensure accurate pattern transfer.

Third, UV exposure is conducted with high-precision photo tool negatives. Under vacuum alignment, ultraviolet light cures the designed pattern areas into a strong acid-resistant protective layer. Uncovered areas remain soft and soluble for the next developing stage. Double-sided exposure ensures symmetrical precision for through-hole structures.

Fourth, alkaline developer washes away unexposed photoresist to fully expose the metal zones that require etching. After strict visual inspection, thermal curing strengthens the mask’s chemical resistance, ensuring stability during high-temperature spraying etching.

Fifth, the core chemical etching process begins. Different metal materials use customized etchants. Stainless steel, brass, phosphor bronze and nickel alloys adopt ferric chloride-based solution. Aluminum uses buffered mixed acid, while titanium uses specialized acid formulas. Manufacturers precisely control temperature, spray pressure and conveyor speed to achieve consistent vertical etching depth, either full through-cut or accurate half-depth etching. The isotropic etching nature naturally creates ultra-smooth, rounded edges with zero burrs and no metal recast layers.

Sixth, after reaching the required dimensions, residual photoresist is fully stripped. Multi-stage pure water rinsing eliminates all chemical residues to prevent oxidation, discoloration and hidden corrosion.

Finally, post-treatment and quality inspection complete the production process. Stainless steel, aluminum and titanium parts receive passivation treatment to restore natural anti-corrosion performance. Optional surface finishes include brushing, blackening, sandblasting and anti-fingerprint coating. Every batch is inspected by optical measuring equipment to guarantee dimensional accuracy, flatness and appearance quality.

Photo etching on metal supports a wide range of industrial metals, including 304, 316L, 201 and 430 stainless steel, copper, brass, phosphor bronze, beryllium copper, aluminum alloy, titanium alloy and nickel-based alloys. The processing thickness ranges from 0.01mm ultra-thin foil to 2.0mm sheet, covering nearly all thin precision metal manufacturing requirements.

Compared with traditional machining, metal photo etching provides irreplaceable technical advantages. It produces completely stress-free components without deformation, work hardening or fatigue damage, which is essential for elastic shrapnels, sensor contacts and ultra-thin conductive parts. It delivers naturally burr-free edges without secondary deburring or polishing, greatly improving assembly efficiency and product stability.

In addition, photo etching supports precise half-depth etching in one forming process, creating bending grooves, positioning steps and anti-slip textures that stamping and laser cutting cannot achieve. Without the need for expensive hard molds, it enables fast prototyping within 24 to 48 hours and offers excellent cost performance for small-batch, complex and customized metal parts.

Typical industrial applications include EMI shielding components, heat sink grids, precision gaskets, micro filter meshes, battery collector nets, optical slits, encoder gratings, medical micro components and aerospace thin shims.

To conclude, photo etching on metal is a reliable, flexible and high-precision subtractive manufacturing technology. With stress-free performance, burr-free quality, controllable half etching and wide material compatibility, it continues to be the optimal solution for complex thin metal components in high-end precision industries worldwide.