Photo Etched Filtration Media

Precision Openings in Thin Metal Foil

Photo etched film is a perforated metal foil or sheet.

Representative circular and semicircular filter foils

Product options from the supplier catalogue. Material grade and the selected aperture/thickness combination require confirmation.

Design Freedom

The photo tool defines the opening pattern and component outline. Unperforated margins, support lands and fixing details can be incorporated into the drawing. Digital artwork also allows pattern changes without a dedicated punching die.

Two Separate Design Choices

The external contour locates the part in the assembly; the micro hole pattern performs the filtration. Specify both independently - for example, a circular disc with elongated openings.

Photochemical Etching

A light sensitive resist protects selected areas of the metal. After exposure and development, chemical etching removes the exposed metal to form the openings and outer profile.

Prepare the Metal. Select the alloy and thickness, cut the sheet and clean the surface.

Image the Pattern. Apply photoresist, expose the artwork and develop the areas that will be etched.

Etch the Openings. Use a controlled chemical process to remove the unprotected metal.

Finish and Inspect. Strip the remaining resist, clean and dry the part, then inspect it against the drawing.

Published Capability Figures

* The catalogue gives these as general capability figures, without a linked material/thickness combination or dimensional tolerance. “Wire diameter” needs clarification for solid foil; specify the residual web/land width on the drawing.

Confirm the Combination

Minimum aperture, remaining web and tolerance depend on foil thickness, alloy and etch profile. The smallest feature value must not be assumed achievable across the entire thickness range.

A stated hole diameter is a dimensional feature, not a demonstrated particle retention efficiency. Confirm the finished opening and the filtration test basis for the intended duty.

Specify More than Hole Diameter

Opening geometry and the remaining metal web

Round openings. Specify diameter d, centre to centre pitch p, array arrangement and foil thickness. For equal pitch in a square array, the minimum web is g = p − d.

Elongated openings. Specify width W, total length L, end radius, spacing and orientation. Confirm the required particle retention under the actual flow and contamination conditions.

Round Holes on a Square Array

Open Area (%) = 100 × πd² / (4p²)

Calculated examples for an ideal perforated field; solid margins and supports reduce the open area of the complete part. These examples do not confirm manufacturability or pressure loss performance.

Control the through Thickness Profile

Etching removes metal laterally and through its thickness, so openings may taper or form a cusp. Agree the aperture measurement plane and any required installation direction.

A conical or other engineered pore profile is a specific design option; it should be confirmed on the drawing rather than assumed for every etched foil.

Integrate the Foil into the Filter Assembly

Applications include precision screens, filter plates and cartridge media for chemical, petroleum, food and pharmaceutical processing, alongside synthetic filament spinning.

For a spinning application, review the foil within the approved spin pack arrangement, including the upstream media, support components, distribution plate and spinneret. The assembly drawing determines its position and orientation.

Process and Objective. Identify the polymer or fluid grade, contamination concern, current filter reference and the quality improvement sought. Include throughput, viscosity basis and operating temperature.

Mechanical Duty. State operating pressure, maximum differential pressure, pressure cycling and the supported span. Include support details, foil flatness, sealing lands and any clamping features.

Aperture and Drawing. Supply the external contour, active area, thickness, aperture geometry, pitch, tolerances and measurement plane. Identify mounting holes, edge details and the drawing revision.

Material and Cleaning. Confirm the exact alloy grade, cleaning chemistry, temperature and reuse method. Handling, washing and installation must preserve the thin foil and its openings.

Inspection and Supply. Agree aperture sampling, dimensional inspection, surface cleanliness, material documentation and traceability. Include trial quantity, expected consumption and delivery requirement.

Trial Acceptance

Compare initial pressure loss, pressure rise during operation, run duration and downstream quality at matched conditions. For spinning, record spinneret blockage and filament breaks against a defined baseline.

The supplier page does not give a complete pressure, temperature or efficiency rating for a finished filter. These limits depend on the selected material, geometry and supported assembly.