Overview

A custom 304 stainless steel code wheel is a thin rotary or linear encoder disc with precisely spaced code tracks and index slits, produced by photochemical machining rather than stamping or laser cutting. A photoresist mask is exposed with the track artwork, developed, and the unprotected 304 stainless sheet is dissolved in a controlled ferric chloride spray, so slit width, tooth width and division accuracy are set by the artwork and etch time instead of die pressure. Typical stock is 304/316L stainless between 0.08 mm and 0.40 mm, chosen for flatness, corrosion resistance and the ability to hold a burr-free, low-reflectance edge that keeps encoder signal contrast high.

For motion-control and encoder buyers, a custom 304 stainless steel code wheel solves three recurring problems: punched slits carry rolled burrs and edge waviness that add signal jitter, fine code tracks at 0.06 mm must hold division accuracy across a full revolution, and any heat tint or recast layer degrades the matte, low-reflectance surface an optical reader needs. Chemical machining forms every slit on a sheet at the same rate, holding division and duty cycle consistent from the first sample through volume production, while leaving the disc flat, stress-free and symmetric on both faces.

Parameter Window

• Available Materials: 304 and 316L stainless steel; also copper and nickel for mixed encoder builds
• Material Thickness Range: 0.08–0.40 mm
• Tolerance: ±0.008 mm on slit width, ±0.01 mm on track position and division
• Minimum Feature: 0.06 mm code-track slit width, 0.08 mm tooth width
• Surface Options: electropolishing, passivation, matte blackening, anti-glare coating, ultrasonic cleaning
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & Nesting — Convert the code tracks and index slits to vector art, verify slit-to-thickness and division rules, and lay out panels with shared fiducials.
2. Material Certification & Prep — Verify 304 grade, mill certificate and thickness, inspect flatness and surface, then shear to exposure size.
3. Cleaning & Lamination — Degrease and laminate dry-film resist on both faces under matched heat and pressure without trapped bubbles.
4. Dual-Side UV Exposure — Expose the track artwork from top and bottom in register so both faces etch symmetrically toward clean slit edges.
5. Development — Wash out unexposed resist to open the slit areas and inspect for residue that would blunt a code edge.
6. Controlled Etching — Spray 304-matched ferric chloride, tuning time, temperature and conveyor speed to hold slit width and avoid undercut.
7. Stripping & Blackening — Strip resist, neutralize, then apply matte blackening or electropolish for a low-reflectance, burr-free finish.
8. Inspection & Packaging — Measure slit width, tooth width and division accuracy on a vision system, verify flatness, then pack between liners.

Core Advantages

1. Burr-free code edges: Chemical removal leaves no rolled burr or recast layer, so signal jitter stays low and contrast stays high.
2. No die cost: Each track pattern is a new film, keeping prototype discs and frequent resolution changes economical without a blanking tool.
3. Fine division accuracy: 0.06 mm slits and 0.08 mm teeth hold ±0.008 mm with ±0.01 mm division across a full revolution.
4. Stress-free flatness: With no shear or heat input, the disc stays flat, so mounting on a hub will not warp the code tracks or skew the reader gap.
5. Matte low-reflectance finish: Blackening and passivation give a stable dark surface that suppresses ghost reflections in the optical path.
6. Repeatable custom tracks: A custom 304 stainless steel code wheel can combine multiple tracks, index marks and mounting holes on one disc, reproduced from first article to volume.

Typical Applications

• Rotary optical encoders: Code discs where slit-edge quality sets resolution and signal contrast.
• Linear encoder scales: Index and code tracks for stage position feedback and metrology axes.
• Motor feedback discs: Hub-mounted wheels for servo and stepper commutation and speed sensing.
• Robotics joint sensors: Compact code wheels for joint angle and motion feedback.
• Metrology & index plates: Division plates for calibration fixtures and rotary tables.
• Industrial automation readers: Low-reflectance code tracks for harsh-environment encoder heads.

Design Notes & Process Considerations

1. Slit-to-thickness ratio: Keep slit width at or above roughly the sheet thickness; very fine slits in thick stock distort from undercut.
2. Division and duty cycle: State slit width, tooth width, line count and division accuracy, not just a nominal resolution, for reliable signal quality.
3. Grade and datum: Choose 304 or 316L by environment, and define the hub datum, concentricity and index-mark position on the drawing.
4. Blackening and reflectance: Define matte finish, optical density and post-coat slit tolerance, since coatings slightly change the effective aperture.
5. Tie bars and borders: Leave adequate tie bars and process borders, and specify final singulation so thin teeth survive stripping and blackening.
6. Handling and cleanliness: With a custom 304 stainless steel code wheel, specify liner packaging, fingerprint control and residual-ion limits for clean encoder assembly.