Overview

Nickel grating etching uses photochemical machining to cut periodic slit-and-line patterns into thin nickel foil, producing encoder scales, optical gratings and diffraction masters with edge definition that mechanical ruling cannot match at this thickness. A photoresist mask is exposed from high-resolution film, developed, and the unprotected metal is dissolved so the slits are formed inside the foil rather than scribed onto it. Pure nickel Ni200/Ni201 and NiFe 52/48 are the standard substrates, run at 0.02–0.3 mm, with line and slit widths down to 0.02 mm and pitches to 0.05 mm.

For optical and motion-control buyers, nickel grating etching removes three constraints: stamped grids cannot hold a constant pitch, electroformed masters are slow to revise, and laser ablation leaves a heat-affected rim that scatters light. Because the pattern comes from a film, pitch and duty cycle stay identical from the first article to volume production, which is what an incremental encoder or spectrometer depends on. Blackening or matte finishing can be added to suppress stray reflection without changing the slit geometry, and a new pitch is simply a new film rather than a new tool.

Parameter Window

• Available Materials: pure nickel Ni200/Ni201, NiFe 52/48, with 304/316L stainless steel and copper as alternatives
• Material Thickness Range: 0.02–0.3 mm
• Tolerance: ±0.005 mm on line width and pitch, ±0.01 mm on pattern position
• Minimum Feature: 0.02 mm slit, 0.02 mm line, pitch down to 0.05 mm
• Surface Options: black oxide matte, nickel plating, passivation, anti-reflection dull finish, anti-tarnish packaging
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & Pattern Review — Convert the grating layout to vector artwork and verify line width, pitch and duty cycle against foil thickness.
2. Material Selection — Match Ni200/Ni201 or NiFe temper and flatness to the required thermal and mechanical stability.
3. Cleaning & Lamination — Degrease the foil and laminate thin dry-film resist on both faces without stretching the pattern.
4. UV Exposure — Expose through high-resolution film with the grating axis registered to the sheet edge for low cumulative error.
5. Development — Wash out unexposed resist to open the slits, then inspect under magnification for scumming or broken lines.
6. Etching — Spray a nickel-compatible etchant with tight time and temperature control to hold straight, vertical sidewalls.
7. Stripping & Finishing — Remove resist, neutralize, then blacken, plate or passivate to suppress reflection and oxidation.
8. Inspection & Packaging — Measure pitch, duty cycle and cumulative error against the approved sample, then pack flat in anti-tarnish film.

Core Advantages

1. Sub-0.02 mm features: Slit and line widths down to 0.02 mm are held on 0.05 mm pitch, far beyond what stamping can resolve.
2. No hard tooling: A new pitch or duty cycle is a new film, so prototype gratings and custom scales stay economical.
3. Pitch consistency: The whole grating etches at one rate, so cumulative error and signal contrast stay uniform across the scale.
4. Burr-free optical edges: Chemical removal leaves no recast rim or burr, keeping scattered light and signal noise low.
5. Flat, stress-free foil: No mechanical force is applied, so thin nickel stays flat and bonds evenly to a glass or metal carrier.
6. Material stability: NiFe 52/48 keeps the nickel grating etching dimensionally stable over temperature for precision encoders.

Typical Applications

• Rotary and linear encoder scales: Fine incremental gratings etched in 0.05–0.1 mm nickel for motor feedback.
• Spectrometer entrance slits: Precise slit arrays that set resolution without a ruled master.
• Optical diffraction gratings: Periodic line fields for educational and analytical instruments.
• Moire and alignment targets: Registered grid patterns used for machine-vision calibration.
• Encoder code discs: Radial grating patterns combined with an index track in one foil.
• Shielding and EMI grids: Fine mesh where optical clarity and conductivity must coexist.

Design Notes & Process Considerations

1. Line-to-thickness ratio: Keep the slit at least 1 × foil thickness, or taper will narrow the opening before breakthrough.
2. Duty cycle callout: State the line-to-space ratio and target diffraction or signal contrast, not just the nominal pitch.
3. Cumulative error: Specify allowable pitch error over the full scale length, since a small per-line drift adds up.
4. Grating axis: Mark the reference axis and datum on the drawing so exposure registration follows the measurement direction.
5. Blackening thickness: Call out the matte coating and confirm it does not bridge slits narrower than 0.03 mm.
6. Handling and flatness: Require flat, anti-tarnish packaging, because thin nickel foil creases easily and cannot be re-flattened.