Overview

A roll to roll photochemical etching process runs a continuous metal coil through cleaning, lamination, exposure, development, etching and stripping stations, producing precision parts reel-to-reel instead of one sheet at a time. Stainless steel 304/316L and copper alloys 0.03–0.30 mm thick and 100–300 mm wide are unwound under controlled tension, laminated with dry-film resist on both faces and exposed through registered artwork as the web advances. A matched etchant sprayed in-line removes the unprotected metal, so burr-free components emerge on the take-up reel ready for die-cutting or assembly.

For a continuous line the two variables that decide yield are registration between stations and line speed, and roll to roll photochemical etching ties them together with web-tension and encoder feedback. Top and bottom artwork are aligned to sprocket or fiducial holes within ±0.02 mm, while conveyor speed of 0.5–3 m/min is held with etchant concentration and temperature so dwell time stays constant along the whole coil. Because the web never stops, the first metre and the thousandth metre see the same chemistry, which is why the route suits high-volume lead frames, meshes and contacts.

Parameter Window

• Available Materials: stainless steel 304/316L, copper C1100/C194, nickel alloys, phosphor bronze
• Material Thickness Range: 0.03–0.30 mm; coil width 100–300 mm
• Tolerance: feature ±0.02 mm, station-to-station registration ±0.02 mm, pitch ±0.02 mm
• Minimum Feature: 0.08 mm line, 0.10 mm gap, sprocket/fiducial pitch held along the coil
• Surface Options: in-line passivation, plating, adhesive lamination, protective film, slit or sheeted output
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Coil Prep & Artwork — Set the repeat pattern and sprocket/fiducial pitch, and compensate side etch at 0.6–0.8 × thickness per side.
2. Material Selection — Choose 304 for stiffness or C194 copper for conductivity, and verify coil width, thickness and camber.
3. In-Line Cleaning & Lamination — Degrease and laminate dry-film resist on both faces as the web advances under constant tension.
4. Registered UV Exposure — Expose top and bottom artwork through a step-and-repeat head aligned to the fiducial holes on the moving web.
5. In-Line Development — Wash out unexposed resist across the full width, then inspect for scumming without stopping the line.
6. In-Line Etching — Spray the matched etchant at fixed concentration, temperature and line speed so dwell time is constant.
7. Stripping & In-Line Finish — Strip resist, neutralize, then passivate, plate or laminate adhesive before the take-up reel.
8. Rewind & Inspection — Verify registration, feature size and pitch from sampled metres, then rewind with a protective interleaver.

Core Advantages

1. Tight station registration: Fiducial-based exposure holds top-to-bottom and station-to-station alignment within ±0.02 mm.
2. Constant dwell time: Line speed locked to chemistry gives the same etch depth from the first metre to the last.
3. High throughput: Continuous web processing removes sheet-by-sheet handling, cutting cost on long runs.
4. Burr-free reel output: Chemical removal leaves clean edges suitable for automatic assembly and die-cutting.
5. Stable web tension: Closed-loop tension control keeps the coil flat, so fine features do not drift across the width.
6. Continuous, low unit cost: roll to roll photochemical etching runs one coil from exposure to reel, so volume parts avoid sheet handling and per-piece setup.

Typical Applications

• Reeled lead frames and contacts: Continuous strips for semiconductor and connector assembly.
• Precision meshes and filters: Long runs of filtration and shielding mesh delivered on reels.
• EMI and shielding cans: Roll-fed components for consumer electronics volume production.
• Flexible circuit and busbar stock: Copper patterns for power and signal distribution.
• Encoder and code strips: Long, repeat-pattern optical scales cut from a continuous coil.
• Adhesive-backed parts: In-line lamination for labels, gaskets and decorative trims.

Design Notes & Process Considerations

1. Fiducial design: Add sprocket or fiducial holes at a fixed pitch so every station can register to the same datum.
2. Line speed and dwell: State the target line speed and allow the shop to set it from etch-depth coupons, since speed defines dwell.
3. Web tension: Specify the tension window, because too much tension stretches thin foil and shifts pitch.
4. Camber and width: Give coil width, camber tolerance and edge trim allowance, or the pattern drifts off-centre.
5. Registration method: Agree how alignment is measured between top/bottom and between stations, with sampled metres as record.
6. Reel format: roll to roll photochemical etching output should define core diameter, winding direction, splice marks and interleaver.