Overview

A micro filter mesh etching process produces precision filtration screens by dissolving unprotected metal through a photoresist mask, so thousands of pores are opened at the same time instead of being punched or drilled one by one. Stainless steel 304/316L, copper and nickel alloys between 0.03 and 0.5 mm are laminated, exposed with the pore pattern and developed, then sprayed with a matched ferric-chloride etchant that leaves smooth, burr-free pore walls with no recast layer. Because every pore on the sheet sees the same chemistry for the same time, pore diameter stays uniform from the centre to the edge of a full panel.

For a filter, the number that governs performance is pore-size uniformity, not just the nominal diameter, and micro filter mesh etching holds it by controlling etchant concentration, temperature and conveyor speed together. Side etch is compensated in the artwork by roughly 0.7–0.9 × material thickness per side, so a 0.10 mm pore finishes within ±0.01 mm while the web between pores stays intact. The finished screen is passivated and cleaned so no loose burr can shed into the flow, and because the tooling is only a film, a 5 µm change in rating is a quick artwork revision rather than a new die.

Parameter Window

• Available Materials: stainless steel 304/316L/316Ti, copper C1100, nickel 200/201, Hastelloy on request
• Material Thickness Range: 0.03–0.5 mm (0.05–0.2 mm typical for fine ratings)
• Tolerance: pore diameter ±0.01 mm, pitch ±0.02 mm, open area ±2% of target
• Minimum Feature: 0.05 mm pore with 0.05 mm web; pore-size CV ≤ 3% across 300 mm panel
• Surface Options: passivated, electropolished, PTFE/nano coating, ultrasonic cleaned, framed or bonded to a support ring
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork & Etch Factor — Draw the pore array with land undersized by the measured side-etch factor, about 0.7–0.9 × thickness per side, so finished pores hit the target micron rating.
2. Material Selection — Choose 316L for chloride service or copper/nickel for conductivity, and verify thickness and surface finish before lamination.
3. Cleaning & Lamination — Degrease the foil and laminate dry-film resist on both faces, checking that no bubble bridges the narrow webs between pores.
4. UV Exposure — Expose the pore pattern through high-resolution film registered to the sheet edge for panel-level accuracy.
5. Development — Wash out unexposed resist to open every pore, then inspect for scumming that would close the smallest openings.
6. Etching — Spray ferric chloride at controlled concentration, temperature and conveyor speed to hold pore diameter and sidewall quality.
7. Stripping & Passivation — Strip resist, neutralize, then passivate or electropolish and ultrasonically clean to remove any loose particle.
8. Inspection & Packaging — Measure pore diameter and open area by optical sampling, verify web integrity, then pack flat between liners.

Core Advantages

1. Uniform pore size: All pores on a sheet etch at the same rate, so the micron rating holds across the full panel instead of drifting at the edges.
2. Burr-free flow path: Chemical removal leaves no rolled burr or punch burr, so particles are not shed downstream and pressure drop stays low.
3. Stable open area: Compensated artwork keeps the web width constant, locking open area to ±2% of the design target.
4. No recast or work hardening: Etched walls stay metallurgically clean, so the screen can be bonded or welded without cracking.
5. Fine ratings at thin stock: 0.05 mm pores with 0.05 mm webs are practical on 0.05 mm foil where stamping would tear the web.
6. Fast rating changes: micro filter mesh etching swaps a film to move the pore size, so a new micron rating is sampled in days without tooling cost.

Typical Applications

• Hydraulic and fuel filtration: Stainless screens rated 10–100 µm that trap particles without shedding burrs into the line.
• Medical and lab sieves: 316L meshes for cell sorting and analysis where pore uniformity drives cut accuracy.
• Chemical process filters: Corrosion-resistant 316L/Hastelloy screens for aggressive fluids and high-temperature flow.
• Food and beverage screening: Passivated meshes for sieving and clarification that are easy to clean and sanitize.
• Aerospace fuel and air: Lightweight screens with controlled open area for fuel, bleed-air and debris filtration.
• Battery and fuel-cell media: Nickel or copper meshes used as current collectors and diffusion layers with uniform porosity.

Design Notes & Process Considerations

1. Pore-to-web ratio: Keep the web at least as wide as the foil thickness, or the narrow land will break through during etching.
2. Etch factor callout: State the side-etch factor, typically 0.7–0.9 × thickness per side, and let the shop set it from a test coupon.
3. Rating definition: Specify whether the rating is absolute or nominal and the test method, so pore diameter and open area are measured the same way.
4. Open area versus strength: Higher open area lowers pressure drop but weakens the web; balance the two against differential pressure.
5. Cleanliness and burr: Require passivation and ultrasonic cleaning, and call out a maximum particle shed count for critical flow paths.
6. Flatness and support: Bond the mesh to a support ring when differential pressure is high, and specify flatness per 100 mm.