Precision metal etching, also widely called photochemical machining (PCM) or photo etching, is a non-contact subtractive metal fabrication technology. It uses photoresist lithography and controlled chemical etchant to selectively remove unwanted metal from thin metal sheets, forming complex micro structures without mechanical cutting force or heat damage.

How Precision Metal Etching Works

1. CAD artwork preparation: Convert part drawings into phototool artwork for pattern exposure.
2. Metal sheet cleaning: Fully degrease and clean the raw metal substrate to ensure photoresist adhesion.
3. Photoresist coating: Apply light-sensitive photoresist film on both sides of the metal sheet.
4. UV exposure: Transfer the design pattern onto the photoresist by ultraviolet light exposure.
5. Developing: Wash away unexposed photoresist to expose the metal areas that need to be etched.
6. Chemical etching: Circulated etchant sprays both sides of the sheet, dissolving exposed metal selectively.
7. Stripping: Remove the remaining cured photoresist mask after etching completes.
8. Inspection & finishing: Dimensional inspection, deburr, cleaning and secondary surface treatment as required.

Core Advantages

1. Burr-free & stress-free: No mechanical impact during processing, parts retain original metal mechanical properties, no deformation.
2. Excellent micron-level precision: Capable of producing ultra-fine holes, slots and intricate patterns with tight tolerances. Feature resolution is not limited by cutting tool size.
3. Low tooling cost & fast iteration: No expensive hard stamping dies. CAD modification can be finished quickly for prototype and mass production.
4. Uniform etching on thin metals: Works perfectly for ultra-thin sheets from 0.01mm upwards, maintains flatness across the whole panel.
5. Wide material compatibility: Available for stainless steel, copper, nickel, kovar, nitinol, molybdenum, brass and many alloy materials.

Typical Applications

• Semiconductor: SMT stencils, shadow masks, lead frames, ultra-fine metal meshes
• New energy: Fuel cell bipolar plates, vapor chamber flow channels, battery conductive shims
• Medical: Nitinol surgical components, precision filters, medical micro spring parts
• Aerospace & instrument: Encoder discs, precision shims, spacers, sensor metal components
• Consumer electronics: EMI shielding cans, speaker grilles, etched nameplates

Design Considerations

1. Material thickness directly determines minimum feature size and tolerance. General rule: minimum hole width equals material thickness.
2. Side undercut must be calculated in drawing design for tight tolerance requirements.
3. Best suited for thin sheet metal; thicker plates will increase etching time and cost.
4. Complex multi-layer or deep 3D structures are not recommended for this process.
5. Batch flexibility: same photo tool works for prototype, small batch and mass production.