Overview

Reel to reel photo etching is a photochemical process that etches fine patterns into continuous metal strip as it runs coil to coil, rather than cutting sheets one panel at a time. The strip is cleaned, laminated with dry film resist, exposed through precision artwork and developed, then the unprotected metal is dissolved in a matched etchant while the web advances under controlled tension and line speed. Because every feature is formed in the metal itself, the result is a burr-free strip with crisp edges, and the same artwork repeats identically for the entire reel length — from the first repeat to the hundred-thousandth.

This continuous format is what makes reel to reel photo etching economical for volume builds. A coil runs through cleaning, lamination, exposure, development, etching and stripping as one uninterrupted flow, so per-part handling drops to nearly zero and feature registration is locked by the artwork rather than by individual fixturing. Materials are typically stainless steel 304/316L, copper C1100/C1020, nickel Ni200 and Alloy 42, supplied between 0.02 mm and 0.3 mm thick. The process suits any application that needs thousands of fine, repeatable parts on a strip — connector terminals, leadframes, shielding grids, sensor diaphragms and battery busbars among them.

Parameter Window

• Available Materials: stainless steel 304/316L, copper C1100/C1020, nickel Ni200, Alloy 42, beryllium copper
• Material Thickness Range: 0.02–0.3 mm strip, 0.01 mm foil on request
• Tolerance: ±0.01 mm on feature size, ±0.02 mm on repeat pitch
• Minimum Feature: 0.05 mm line width and 0.05 mm slot at 0.05 mm stock
• Surface Options: bright annealed, electroplated Ni/Au/Sn, passivated, adhesive backing
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork Review — Convert customer files to vector artwork, check minimum line widths against strip thickness, and confirm pilot-hole and registration-mark positions.
2. Coil Preparation — Load the master coil, verify strip width, surface finish and edge quality, and set unwind tension to prevent camber and wrinkles.
3. Cleaning & Lamination — Degrease the moving web and laminate dry film resist under heat and pressure with no air entrapment under fine traces.
4. UV Exposure — Expose both sides through registered films while the web is held stationary or indexed, so front and back features align within tolerance.
5. Development — Wash out unexposed resist to open the pattern, then inspect for under-developed traces and residual resist before the etch stage.
6. Continuous Etching — Run the web through a matched etchant at a set line speed and temperature; depth and sidewall quality follow conveyor speed and chemistry control.
7. Stripping & Rinse — Remove the resist, neutralize the strip and rinse, then apply plating, passivation or adhesive where specified.
8. Recoil & Inspection — Rewind onto the customer-specified spool and run in-line vision inspection of critical dimensions before final packing.

Core Advantages

1. No tooling cost: Each pattern change is a new film set, so design revisions and short-to-mid runs start without stamping or progressive dies.
2. Coil-to-coil continuity: Cleaning, exposure and etching run as one flow, cutting per-part handling and keeping lead times short.
3. Locked registration: Feature-to-feature pitch is set by the artwork, so multi-feature parts stay aligned across the entire reel length.
4. Burr-free edges: Chemical removal leaves no roll-over or mechanical burr, so strips feed cleanly through downstream stamping or plating.
5. Tension-controlled flatness: Managed unwind and rewind tension keeps thin strip flat and free of edge curl for subsequent assembly.
6. Fine features at volume: 0.05 mm lines and slots hold across thousands of repeats, which progressive tooling cannot match at this gauge.

Typical Applications

• Connector terminal strips: Fine contact fingers etched into beryllium copper or phosphor bronze strip, wound on reels for automated crimping.
• Leadframes: Dense pin and pad patterns on Alloy 42 or copper strip for semiconductor packaging.
• EMI shielding grids: Dense conductive meshes etched into stainless or nickel strip for enclosure and cable shielding.
• Sensor diaphragms: Thin stainless or nickel foil etched with fine through-holes and flexures for pressure and flow sensors.
• Encoder disks: Fine radial slits and gratings on thin foil for rotary and linear position feedback.
• Battery busbars and tabs: Nickel or copper strip etched with precise cell tabs and current-carrying patterns for battery packs.

Design Notes & Process Considerations

1. Tension and edge: Specify the exact strip width and edge condition; inconsistent camber or burred edges cause web tracking errors and registration drift.
2. Registration marks: Include pilot holes or fiducials on both ends of each repeat so front-to-back alignment can be verified at speed.
3. Line speed versus depth: Deeper or heavier-gauge etching requires a slower line speed; state the target etch depth so chemistry and conveyor speed can be matched.
4. Panel layout: Nest multiple part numbers across the strip width with shared tooling rails to reduce waste and lower unit cost.
5. Thickness uniformity: Call out foil thickness tolerance, because gauge variation shifts etch time and changes feature dimension.
6. Spool specification: State core inner diameter, reel outer diameter, winding direction and interleave material so the finished reel drops into your feed machine.