Overview

Copper aperture etching uses photochemical machining to cut precise round, slit and shaped openings into thin copper foil without mechanical force or a stamping die. A photoresist mask is exposed with the aperture artwork, developed, and the unprotected metal is dissolved in a copper-matched etchant, so hole diameter, roundness and edge quality are set by the artwork and etch time rather than by tool pressure. Typical substrates are C1020/C1100 oxygen-free copper, supplied between 0.02 mm and 0.5 mm. Because the process is chemical, each opening leaves the line flat and burr-free, with a clean knife edge and no rolled lip, die wear or heat tint to scatter stray light at the rim.

For buyers, this process solves three recurring problems. Precision optics need pinholes and slits with true roundness and concentricity that punching cannot hold below 0.1 mm; a dull or burred edge diffracts light and ruins contrast in imaging and spectrometer paths; and every new aperture set would otherwise need a dedicated stamping tool. Chemical machining forms every opening on a sheet at the same rate, holding diameter and edge quality from the first sample through volume production, and copper accepts blackening or plating that suppresses reflections without changing the clear aperture.

Parameter Window

• Available Materials: C1020/C1100 oxygen-free copper, copper alloys; also nickel and 304/316L stainless for mixed builds
• Material Thickness Range: 0.02–0.5 mm
• Tolerance: ±0.01 mm on aperture diameter, ±0.005 mm on concentricity
• Minimum Feature: 0.05 mm pinhole diameter, 0.03 mm edge/web width
• Surface Options: black oxide matte, anti-glare blackening, nickel plating, electropolishing, anti-tarnish
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & Nesting — Convert aperture geometry to vector art, check the edge-to-thickness ratio, and plan sheet layout with shared registration marks.
2. Material Certification & Prep — Verify copper grade, mill certificate and thickness, inspect for scratches and flatness, then shear to exposure size.
3. Cleaning & Lamination — Degrease and laminate dry film resist under matched heat and pressure so no bubbles sit under thin edges.
4. UV Exposure — Expose through high-resolution film with the array registered to the sheet edge for panel-level roundness and concentricity.
5. Development — Wash out unexposed resist to open the aperture areas, and inspect for under-developed residue that would distort the edge.
6. Controlled Etching — Spray copper-matched chemistry, tuning time, temperature and conveyor speed to hold a sharp, burr-free knife edge.
7. Stripping & Blackening — Remove resist, neutralize, then blacken, plate or polish to suppress stray-light reflection without changing the aperture.
8. Inspection & Packaging — Measure diameter, roundness and edge quality on a vision system, verify flatness, then pack on liner or in clean trays.

Core Advantages

1. Burr-free knife edge: Chemical removal leaves no rolled lip, so the rim does not diffract light or throw stray spots into the image.
2. No die cost: Each new aperture set is a new film, keeping prototypes and multi-spec trials economical without a stamping tool.
3. True round openings: 0.05 mm pinholes and 0.03 mm webs form together across a sheet, with tight roundness and concentricity spread.
4. Stress-free flatness: With no shear or heat input, thin foil stays flat, so the part seats squarely in a lens barrel or stacked assembly.
5. Stray-light control: Copper takes blackening, nickel plating or polishing that pushes rim reflection down without changing the clear aperture.
6. Repeatable micro-apertures: copper aperture etching locks diameter and edge into the film and process settings, so cross-batch openings stay identical for optical calibration.

Typical Applications

• Lens diaphragms: Light-limiting aperture plates for camera and industrial lenses, round and clean-edged to avoid flare.
• Spectrometer pinholes: Pinhole plates for spectroscopy and confocal paths where 0.05 mm-scale holes set resolution.
• Encoder slit masks: Slit masks for optical encoders with uniform width and accurate position for even pulse output.
• Beam-shaping masks: Shaped opening plates for laser and illumination systems that control spot geometry and boundary.
• Analytical apertures: Limiting apertures for biochemical and particle analyzers with stable, repeatable diameters.
• Medical optics: Small apertures for endoscopic and diagnostic light paths combining dimensional accuracy with a cleanable surface.

Design Notes & Process Considerations

1. Edge-to-thickness ratio: Keep the narrowest web at or above material thickness; too thin a web distorts from undercut and dulls the knife edge.
2. Roundness and concentricity: State diameter, roundness tolerance and datum-referenced concentricity; give a common datum for multi-aperture arrays.
3. Stray-light finish: Name the blackening or plating system and reflectance target, and keep the film thin so the clear aperture does not shrink.
4. Nesting and tie bars: Leave enough tie bars and process borders, and specify the final cut method so thin webs survive stripping and cleaning.
5. Thin-foil handling: For foil below 0.05 mm, specify a carrier or liner and call out flatness and cleanliness to avoid creases and fingerprints.
6. Cleanliness and inspection: With copper aperture etching, define burr-free edges, residual-ion limits and clean packaging, with full vision inspection for optical parts.