Overview

Gasket chemical etching is a photochemical machining process that dissolves unprotected metal to form a sealing gasket, rather than blanking it with a punch or melting it with a laser. A photoresist mask is exposed with the gasket outline, bolt holes and any internal slots, developed, and the exposed metal is removed by a matched etchant spraying from both sides of the sheet. Because metal is dissolved atom by atom, the process leaves no burr, no rolled edge and no recast layer — the three defects that most often break a seal. Typical foils are stainless steel 304/316L, copper, nickel and titanium, between 0.03 mm and 0.5 mm thick.

The process itself is what makes the part dependable. Etching introduces no mechanical or thermal stress, so a thin gasket stays dead flat instead of curling after blanking; it cuts equally from both faces, so holes and edges stay sharp and symmetric; and it etches every feature on a panel at the same rate, so bolt-hole pitch repeats within ±0.03 mm across a whole batch. Gasket chemical etching therefore suits sealing parts where flatness, edge quality and hole-position accuracy matter more than material removal speed.

Parameter Window

• Available Materials: stainless steel 304/316L, copper, nickel, titanium foils
• Material Thickness Range: 0.03–0.5 mm
• Tolerance: ±0.03 mm on outline and apertures, ±0.03 mm on bolt-hole pitch
• Minimum Feature: 0.05 mm hole diameter, 0.15 mm slot width at 0.1 mm stock
• Surface Options: as-etched, passivated, tin-plated, nickel-plated, annealed for flatness
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork Preparation — Convert the gasket drawing to vector, scale the outline to account for etch undercut, and set the hole pattern on its true pitch.
2. Foil Selection — Match alloy, temper and gauge to the seal; thinner foils for crush seals, work-hardened stock where spring recovery is needed.
3. Cleaning & Lamination — Degrease the foil and laminate dry film resist on both faces so the etchant attacks evenly from each side.
4. Double-Sided Exposure — Expose front and back film in register so holes and edges etch symmetrically and stay vertical.
5. Development — Wash out unexposed resist to open the outline and apertures, then check that fine holes are fully developed through.
6. Etching — Spray etchant from both sides at controlled temperature and conveyor speed; undercut is held below half the foil thickness.
7. Stripping & Finishing — Remove resist, neutralize, then passivate, plate or anneal; annealing flattens any residual curl in very thin foil.
8. Inspection & Packaging — Verify outline, hole pitch, thickness and flatness with optical and gauge checks, then pack flat on liners.

Core Advantages

1. Burr-free by nature: Dissolution leaves no burr or roll-over, so the sealing face needs no secondary deburring or tumbling.
2. Stress-free and flat: No mechanical force or heat means thin foils stay flat and do not spring back or curl after blanking.
3. Symmetrical edges: Etching from both faces keeps hole walls and edges sharp and vertical, with no die-side roll-over.
4. Fine holes and slots: Holes down to 0.05 mm and narrow slots etch cleanly, far below what a punch can blank in thin foil.
5. Tight, repeatable pitch: Every gasket on a panel etches at the same rate, so bolt-hole pitch holds ±0.03 mm batch after batch.
6. No tooling, no minimums: A design change is a new phototool, so prototypes and small lots run without a die. Gasket chemical etching is therefore the lowest-cost route to a sealing part that actually seals.

Typical Applications

• Crush gaskets: Thin copper or nickel rings that deform to seal between mating faces in sensors and fittings.
• Flange gaskets: Round and rectangular sealing gaskets with bolt-hole rings for pipe and valve joints in 0.3 mm stainless.
• Vacuum gaskets: Dead-flat titanium seals for vacuum flanges that demand clean, burr-free edges.
• Battery sealing gaskets: Nickel foils with precision apertures for cell sealing in battery packs.
• EMI gaskets: Conductive spring-finger gaskets etched in beryllium copper for shielding enclosures.
• Spacer gaskets: Thin stainless shims that set a precise gap while sealing between stacked plates.

Design Notes & Process Considerations

1. Slot width versus thickness: Keep the narrowest slot at 1.0 × foil thickness or 0.15 mm, whichever is larger, or the slot will etch unevenly.
2. Undercut allowance: Etching cuts sideways as it cuts down; add an undercut allowance of about half the foil thickness to the artwork.
3. Hole pitch datum: Reference all hole positions from a single datum and state pitch tolerance as ±0.03 mm to match process capability.
4. Flatness and annealing: For foils under 0.1 mm, specify flatness per 100 mm and allow annealing if the part must sit dead flat.
5. Surface and plating: Name the finish — passivation, tin or nickel — and state the service fluid, since plating changes crush behavior.
6. Batch sampling: Define the sampling plan for pitch and thickness; panel-level consistency means a few measured parts represent the whole lot. Gasket chemical etching keeps these tolerances stable because the chemistry, not tool wear, sets the dimensions.