Overview

What are the benefits of photochemical etching? Put simply, photochemical etching — also called photo etching or photochemical machining — is a subtractive process that dissolves selected areas of a thin metal sheet through a photoresist mask, leaving burr-free, stress-free parts. The advantages come from removal being chemical rather than mechanical or thermal: no hard die, no cutting force and no heat-affected zone are involved. Below is a direct list of the advantages that matter most to engineers and buyers, with a short explanation of each.

The main advantages are these. Burr-free, stress-free edges: chemical dissolution leaves no roll-over, burr or residual stress, so parts seat flat without secondary deburring. No hard tooling: a new part number is simply a new film artwork, which keeps prototypes and low volumes economical and turns revisions in days. Fine feature capability: lines and holes down to about 0.05 mm hold at production thickness without distortion. Tight, repeatable tolerance: ±0.02 mm is held across the whole sheet, so assemblies fit without selective rework. Flat, undistorted thin stock: 0.02–2.0 mm sheet stays flat because no force is applied. Broad material and finish choice: stainless, copper and nickel alloys run on one line with passivation or plating matched to the end environment, all under ISO 9001 process control with RoHS/REACH traceability.

Parameter Window

• Available Materials: stainless steel 304/316L, copper, brass, nickel, Kovar, titanium
• Material Thickness Range: 0.02–2.0 mm
• Tolerance: ±0.02 mm on critical profiles (down to ±0.01 mm on thin stock)
• Minimum Feature: 0.05 mm line width, 0.08 mm hole diameter at 0.1 mm stock
• Surface Options: passivation, electropolish, Ni/Au plating, black oxide, adhesive backing
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & DFM Review — Convert the drawing into vector artwork and check hole diameters, web widths and bend relief against 0.02–2.0 mm stock before tooling.
2. Material Selection — Choose stainless steel, copper and nickel alloys in the right temper and confirm flatness and surface condition before lamination.
3. Cleaning & Lamination — Degrease the sheet and laminate dry-film photoresist on both faces under controlled heat and pressure.
4. UV Exposure — Expose the part pattern through high-resolution film registered to the sheet datum for panel-level accuracy.
5. Development — Wash out unexposed resist to open the apertures, then inspect for residue in the finest features.
6. Controlled Etching — Spray or immerse in chemistry matched to the alloy, holding ±0.02 mm through time, temperature and conveyor speed.
7. Stripping & Finishing — Remove resist, neutralize, then apply the specified passivation or plating and optional anneal for flatness.
8. Inspection & Packaging — Verify aperture size, profile and flatness against the approved first article, then pack in trays or on liner.

Core Advantages

1. Burr-free edges: Chemical removal leaves no roll-over or heat tint, so parts seat flush without secondary deburring.
2. No hard tooling: A new part number is a new film, keeping low-volume and prototype programs economical.
3. Fine feature capability: Features down to 0.05 mm hold at production thickness without distortion.
4. Tight, repeatable tolerance: ±0.02 mm is held across the whole sheet, so assemblies fit without selective rework.
5. Stress-free flat parts: No mechanical force means thin parts stay flat and dimensionally stable after etching.
6. Material and finish flexibility: stainless steel, copper and nickel alloys run on one line with plating or passivation matched to the end environment. Taken together, the benefits of photochemical etching are strongest on high-mix, low-volume programs that still demand tight consistency.

Typical Applications

• Lead frames: Etched IC and semiconductor lead frames with fine, burr-free fingers.
• Encoder discs: High-resolution optical encoder discs with dense slot patterns.
• Shims and spacers: Precision thickness shims for instrument gap control.
• Filter meshes: Micro-perforated screens for filtration and metering.
• EMI shielding: Thin shielding cans and meshes for RF-sensitive modules.
• Aperture plates: Optical apertures and masks for imaging and sensing.

Design Notes & Process Considerations

1. Feature versus thickness: Keep the minimum web at or above 1.2 × material thickness so narrow ribs do not lift during etching.
2. Tolerance callout: State ±0.02 mm on critical profiles and separate half-etched depth from through-cut dimensions.
3. Hole geometry: Specify diameter, pitch and open area; round entries reduce stress concentration in thin stock.
4. Flatness and burr: Call out flatness per 100 mm and require burr-free edges where parts mate to a housing.
5. Surface and plating: Name the finish and thickness, since plating adds to the final 0.02–2.0 mm stack.
6. Panelization: Group parts with shared registration marks to cut handling cost on repeat volumes; agreeing these six items, a program built around the benefits of photochemical etching moves to production with fewer review cycles.