Overview

Seal ring etching uses photochemical machining to produce flat metal sealing rings whose sealing face carries an etched groove, land or O-ring channel formed in the metal itself. A photoresist mask is exposed with the groove profile, developed, and the unprotected material is dissolved to a controlled depth, so the sealing groove is flat-bottomed, burr-free and repeatable from ring to ring. Materials are typically stainless steel 304/316L, aluminum 5052, copper C1100 and brass, supplied between 0.1 mm and 2.0 mm thick. Because the groove is formed chemically rather than by turning or milling, the ring stays flat and stress-free, and the groove geometry repeats exactly across a full batch without any cutting-tool taper or chatter.

The value of seal ring etching shows most clearly in static sealing applications where flatness and groove profile decide how well the seal beds in. A ring that is bowed or whose groove floor is scored will leak at low clamping loads or distort the elastomer, while an etched ring sits dead flat and holds its groove width and depth within tight limits. Etched rings also suit thin, fragile sections and complex groove patterns that are difficult to machine, letting designers combine a sealing channel with bolt holes, alignment notches and locating features in a single flat part.

Parameter Window

• Available Materials: stainless steel 304/316L, aluminum 5052, copper C1100, brass C2680
• Material Thickness Range: 0.1–2.0 mm
• Tolerance: outline ±0.05 mm, groove depth ±0.02 mm, flatness 0.05 mm per 100 mm
• Minimum Feature: 0.3 mm groove width at 0.5 mm stock
• Surface Options: passivation, electropolish, anodizing (aluminum), nickel plating
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Groove Layout Review — Convert the seal-ring drawing to vector artwork, check groove width and depth against stock thickness and confirm flatness callout.
2. Material Selection — Match alloy and temper to the fluid and pressure; stainless for chemical resistance, aluminum for light weight, copper for soft conformable seals.
3. Cleaning & Lamination — Degrease the sheet and laminate dry film resist so no bubbles sit under the groove area or the sealing land.
4. UV Exposure — Expose through high-resolution film with the groove profile registered to the ring center and bolt-hole pattern.
5. Development — Wash out unexposed resist to open the groove and aperture areas, then inspect for under-developed groove edges.
6. Etching — Immersion or spray etch to a controlled depth, holding groove width and a flat bottom through time, temperature and agitation.
7. Stripping & Finishing — Remove resist, neutralize, then passivate, electropolish or anodize; leveling is available where flatness must be restored.
8. Inspection & Packaging — Verify groove depth, width, flatness and outline on a CMM, then pack rings flat in trays or on liner.

Core Advantages

1. Flat, stress-free rings: Chemical removal introduces no cutting force, so rings stay flat and the sealing land beds evenly under clamp load.
2. Repeatable groove geometry: Groove depth holds to ±0.02 mm and width is set by film artwork, so every ring in a batch seals the same.
3. No tooling or fixtures: Each groove pattern is a new film, so short runs and design changes cost nothing extra in dies or jigs.
4. Burr-free sealing face: The groove and land leave the bath clean, with no burr to nick an O-ring or trap contamination.
5. Complex profiles in one pass: Sealing channels, bolt holes, notches and locating tabs etch together in a single flat part.
6. Material flexibility: Stainless, aluminum, copper and brass run on one line, letting one order mix seal materials without retooling.

Typical Applications

• Flange gasket rings: Flat sealing rings with an etched O-ring channel for pipe and valve flanges.
• Fluid sealing washers: Rings that combine a sealing groove with a center bore for hydraulic and pneumatic fittings.
• Sensor housing seals: Flat sealing rings with locating notches for pressure and temperature sensor ports.
• Vacuum chamber seals: Stainless rings with a controlled sealing land for vacuum and low-outgassing assemblies.
• Battery cell seals: Thin copper or aluminum rings with etched grooves for cylindrical cell sealing.
• Pump and valve seats: Flat sealing rings with concentric grooves for rotary and diaphragm pumps.

Design Notes & Process Considerations

1. Groove width versus depth: Keep groove width at least 2× the etched depth so the bottom stays flat and the sidewalls stay clean.
2. Flatness callout: State flatness per 100 mm, typically 0.05 mm, because a bowed ring cannot clamp evenly onto the sealing face.
3. Groove depth tolerance: Specify groove depth to ±0.02 mm and note whether it is half-etched or through-cut relative to stock.
4. Land width: Keep the sealing land wide enough relative to stock so it does not undercut during etching.
5. Surface finish: Name passivation or electropolish for stainless, and anodizing for aluminum, to protect the sealing face from corrosion.
6. Bolt and alignment features: Combine bolt holes and notches in the same artwork; seal ring etching should always state groove depth, flatness and land width on the drawing.