Overview

Mesh photo etching is the lithographic route to a metal mesh: the hole pattern is generated as a phototool, printed into resist on both faces of the sheet, developed, and then transferred into metal by etchant. Nothing is woven and nothing is punched, so the mesh geometry is whatever the artwork says — hexagonal, round, slot or a graded array — and the strand width and aperture are independent variables rather than consequences of a loom or a die.

The quality of the result is decided in three places. The phototool sets the line width and must be compensated for the small growth that film picks up under changing humidity. Exposure energy and collimation decide whether the resist wall is vertical or undercut, which in turn decides whether the etched hole is straight or barrel-shaped. Development removes the unexposed resist cleanly or leaves a scum that blocks the aperture. Control those three and mesh photo etching will hold a 0.05 mm aperture on a 0.08 mm pitch with an open area above 70%, repeatably across a 300 mm panel.

Parameter Window

• Available Materials: stainless steel 304/316L, copper, nickel, aluminum, nickel-iron alloy
• Material Thickness Range: 0.03–0.5 mm
• Tolerance: ±0.01 mm on aperture, ±0.01 mm on strand width, ±0.05 mm on outer profile
• Minimum Feature: 0.05 mm aperture, 0.03 mm strand, 0.08 mm pitch, open area up to 80%
• Surface Options: as-etched, electrolytic polish, passivation, blackened, adhesive frame, laminated to a support ring
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Mesh Design Review — Calculate open area from aperture and pitch, check strand width against thickness, and confirm the hole shape can be held at the requested density.
2. Phototool Making — Image the pattern at 1:1 or with a stated reduction, apply line-width compensation, and verify critical dimensions on a measuring microscope.
3. Sheet Cleaning — Degrease and micro-etch the surface so the resist bonds evenly; a water-break test confirms the sheet is ready.
4. Resist Coating — Laminate or spin-coat a resist layer of controlled thickness; too thick and fine apertures under-develop, too thin and the resist fails in the etchant.
5. Exposure — Expose both faces under collimated light with the phototool in hard contact, using an energy step test to fix the dose for that resist batch.
6. Development — Develop in a temperature-controlled bath, rinse and dry, then inspect aperture opening and resist adhesion before etching.
7. Etching — Spray etchant from both sides so the two fronts meet mid-thickness and the hole wall stays symmetrical instead of tapering.
8. Strip and Measure — Remove resist, measure aperture, strand, pitch and open area on a sample, then clean, dry and pack flat between interleaves.

Core Advantages

1. Aperture and strand are independent: Unlike weaving, the artwork sets hole size and strand width separately, so a 0.05 mm aperture can sit on a 0.03 mm strand without re-tooling.
2. Straight walls from collimated exposure: Hard-contact exposure under parallel light keeps the resist profile vertical, which produces a near-cylindrical hole rather than a barrel or a cone.
3. Any hole shape in one sheet: Round, square, hexagonal, slot and teardrop apertures can be mixed, and density can be graded across the panel.
4. No weave crimp or drift: There is no interlacing to create thickness variation, so the mesh is flat and the open area is exactly what the drawing states.
5. Repeatable from film: Once the phototool and dose are fixed, every sheet etches to the same geometry, and a replacement batch matches the original without retesting.
6. Thin stock, fine pattern: Foil from 0.03 mm can carry a dense array that would tear or deform under punching, and the part stays flat through the whole run.

Typical Applications

• Filtration mesh: Absolute-rated screens for fuel, hydraulic and process fluids where aperture tolerance sets the retention rating.
• Acoustic mesh: Speaker and microphone grilles with high open area and controlled airflow resistance.
• EMI and RF shielding: Fine aperture arrays that attenuate a target frequency band while staying optically open.
• Optical reticles: Aperture arrays and alignment patterns for sensors and inspection systems.
• Battery and fuel-cell screens: Corrosion-resistant 316L mesh for electrode support and gas diffusion layers.
• Medical filter devices: Burr-free mesh inserts for blood and IV lines where a loose strand is unacceptable.

Design Notes & Process Considerations

1. Open area math: Open area falls quickly as strand width grows; a 0.05 mm strand at 0.1 mm pitch leaves well under half the sheet open, so run the numbers before fixing the pitch.
2. Aperture-to-thickness ratio: Keep the aperture at least equal to the sheet thickness where possible; below 1:1, etch time increases and aperture spread widens.
3. Corner geometry: Square apertures etch with rounded corners of roughly half the strand width, so specify a radius rather than expecting a true 90° corner.
4. Phototool compensation: Film grows and shrinks with humidity, so critical dimensions should be compensated at the phototool stage, not chased in the etch bath.
5. Support and handling: Mesh under 0.05 mm with high open area is fragile; design a solid border or a carrier frame so the part survives packing and assembly.
6. Inspection basis: Define whether aperture is measured at the entry face, the exit face or mid-wall, and state the sampling plan. Mesh photo etching is repeatable only when both sides agree on the same measurement.