Overview

A grating disc supplier provides the thin, slotted metal discs that sit inside rotary and linear encoders, converting mechanical displacement into optoelectronic pulses. Hundreds to thousands of equally spaced radial slots run around the circumference, usually with a separate index track for the zero reference; slot width and pitch consistency set the resolution and signal quality directly. These discs are made by photochemical etching or precision electroforming rather than stamping or laser cutting: photoresist is imaged on both faces, exposed through high-resolution film, developed, and the unprotected metal dissolved in a matched etchant, so slots, the hub bore and the outer diameter form in one pass. Stainless steel 304/316L, nickel, beryllium copper and nickel silver are typical at 0.05–0.50 mm, with slots to 0.02 mm, bars to 0.03 mm and pitch tolerance to ±0.005 mm. Chemical removal leaves slot walls burr-free, heat-tint-free and the disc flat and stress-free, so the signal stays clean and runout low.

From an engineering and sourcing standpoint, what buyers verify when qualifying a grating disc supplier is whether cumulative pitch error around the full circle stays inside ±0.005 mm, whether 0.02 mm slots survive etching without lifting or residue, and whether the anti-reflection finish suppresses stray light at the reader. Stamping curls thin stock and needs a hard die per slot count; laser drilling dense slots leaves heat buildup and slag; etching builds the pattern into the metal and uses panel-level exposure so every disc in a lot shares the same slot width, position and bore. Competent supply also means prototype support: a new slot count is a new film, not a new tool, so sample discs reach the line in days and the approved first article is then locked for volume, shipped with measured critical dimensions and first-article photos.

Parameter Window

• Available Materials: stainless steel 304/316L, nickel, beryllium copper, nickel silver
• Material Thickness Range: 0.05–0.50 mm
• Tolerance: ±0.005 mm on slot pitch and slot width
• Minimum Feature: 0.02 mm slot, 0.03 mm bar at 0.05 mm stock
• Surface Options: black oxide / matte black anti-reflection, electropolish, passivation, anti-glare coating
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & DFM Review — Convert the slot pattern to vector artwork and check slot width, pitch and bore against 0.05–0.50 mm stock.
2. Material Selection — Choose alloy, temper and flatness grade for the target resolution, then flatten the foil before lamination.
3. Cleaning & Lamination — Degrease and laminate dry-film photoresist on both faces so no bubbles sit under the finest slots.
4. UV Exposure — Expose the pattern through high-resolution film registered to the disc-center datum for panel-level accuracy.
5. Development — Wash out unexposed resist to open the slots and inspect the finest gaps for residue.
6. Controlled Etching / Electroforming — Dissolve stainless and copper alloys in matched chemistry, or grow ultra-fine nickel discs by electroforming, holding slot width and wall quality.
7. Stripping & Anti-reflection Finish — Remove resist, neutralize, then black-oxide, matte-coat or electropolish, with anneal when flatness must be restored.
8. Inspection & Packaging — Verify slot width, cumulative pitch error and flatness against the approved first article, then film-mask or tray-pack.

Core Advantages

1. Burr-free, clean slot walls: Chemical removal leaves no roll-over or heat tint, so optical contrast is high with no secondary deburring.
2. Ultra-fine slot capability: 0.02 mm slots and 0.03 mm bars hold their designed shape at production thickness.
3. No hard tooling: A new slot count is a new film, keeping low-volume encoder builds and revisions economical.
4. Tight cumulative pitch: ±0.005 mm is held around the whole circle, so assemblies need no per-disc calibration.
5. Stress-free flat discs: With no mechanical force, thin discs stay flat and radial runout stays low on the hub.
6. Low-reflectivity finishes: stainless steel, nickel and beryllium copper run on one line with black oxide or matte coating matched to the reader — a core reason to qualify a specialist grating disc supplier for high-resolution work.

Typical Applications

• Rotary encoder discs: Incremental discs for servo and motor feedback with dense slots and a clear index track.
• Linear encoder scales: Grating scales for linear displacement with low cumulative error.
• Robotics joint encoders: Compact, thin and light code discs for collaborative robot joints.
• Metrology stages: High-line-count discs for indexing and measurement turntables with stable readouts.
• Index / zero-reference discs: Single-turn absolute zero and reference-mark discs with precise index slot position.
• Optical speed discs: Light-chopping grating discs for speed and angle sensing with anti-glare coating.

Design Notes & Process Considerations

1. Bar versus thickness: Keep the minimum bar at or above about 1.2 × material thickness so narrow ribs do not lift during etching.
2. Pitch error callout: State single-pitch tolerance and full-circle cumulative error separately; one overall figure hides long-period drift.
3. Slot & hub geometry: Specify slot count, width, open area and bore fit; round bore entries reduce stress and the index track needs support.
4. Flatness and runout: Call out flatness per 100 mm and axial runout on the hub, plus burr-free slots, to avoid signal jitter or rubbing.
5. Finish and coating: Name the anti-reflection finish and thickness, since black oxide slightly narrows slots and shifts optical contrast.
6. Panelization: Group discs with shared registration marks to cut handling cost — defining all six points up front shortens sampling with a grating disc supplier considerably.