Overview

Custom diaphragm etching uses photochemical machining to produce thin metal sensing diaphragms with clean edges and repeatable response. A photoresist mask is exposed with the diaphragm profile, developed, and the unprotected metal is dissolved in a matched etchant, so the disc, flexure pattern and any micro features are formed in one pass without mechanical cutting. Typical substrates are 316L stainless steel, nickel and titanium foils, supplied between 0.02 mm and 0.5 mm.

Because the metal is dissolved rather than sheared or lasered, the foil leaves the bath flat, burr-free and free of the heat-affected zone and edge stress that would shift a sensor's zero point or linearity. Thickness and contour are held tightly from part to part, so the same diaphragm deflects identically under pressure across a whole batch. The process also suits micro features and through-holes down to 0.05 mm, which stamping and EDM struggle to deliver on such thin foils.

Parameter Window

• Available Materials: 316L stainless steel, nickel (N4/N6), titanium, Monel
• Material Thickness Range: 0.02–0.5 mm
• Tolerance: ±0.05 mm on profile and hole position, ±0.02 mm on critical thickness
• Minimum Feature: 0.05 mm hole and slot at 0.1 mm stock
• Surface Options: passivation, electropolish, bright anneal, cleanroom wash, vacuum-pack
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork Review — Convert the diaphragm drawing to vector artwork and check flexure width and hole size against foil thickness.
2. Material Selection — Match alloy and temper to pressure range, media compatibility and thermal needs; stainless for general use, titanium for aggressive media.
3. Cleaning & Lamination — Degrease the foil and laminate dry film resist without bubbles or wrinkles on the thin substrate.
4. UV Exposure — Expose the profile through high-resolution film registered to the foil edge for repeatable position.
5. Development — Wash out unexposed resist to open the outline and features, then inspect fine flexures for residue.
6. Etching — Immerse or spray with chemistry matched to the alloy; foil thickness and edge quality are controlled by time and temperature.
7. Stripping & Finishing — Remove resist and neutralize, then passivate, electropolish or clean to the required surface condition.
8. Inspection & Packaging — Verify thickness, profile, flatness and surface against the sample, then pack in cleanroom-grade, lint-free trays.

Core Advantages

1. Repeatable response: Tight thickness and contour control mean every diaphragm deflects identically, keeping sensor output consistent.
2. No heat-affected zone: Chemical removal avoids laser or EDM heat, so the foil keeps its spring properties and zero stability.
3. Burr-free thin foils: Etched edges need no deburring, which protects fragile thin sections that would bend under mechanical finishing.
4. Micro features: Holes and slots down to 0.05 mm hold on foils, supporting venting, bosses and flexure patterns in one pass.
5. Flat and stress-free: The foil leaves the bath flat with no rolled edge, so it mounts cleanly into a pressure housing.
6. Material range: Stainless, nickel, titanium and Monel run on one line. Custom diaphragm etching also supports half-etched corrugations for larger stroke.

Typical Applications

• Pressure sensor diaphragms: Thin foils that deflect under gas or liquid pressure for transmitters and gauges.
• Load cell flexures: Etched metal flexures that translate force into repeatable displacement.
• Microphone and acoustic diaphragms: Thin metal membranes with controlled stiffness for acoustic pickups.
• Valve and regulator diaphragms: Flexible metal discs that seal and actuate under pressure cycles.
• Fuel cell and battery components: Thin metal plates and membranes with micro perforations.
• Optical and instrument membranes: Precision foils for actuators, mirrors and analytical instruments.

Design Notes & Process Considerations

1. Thickness callout: State the nominal thickness and tolerance; response is dominated by thickness, so confirm it before artwork.
2. Flexure versus thickness: Keep flexure or web width at or above 1.5 × foil thickness to avoid uneven etching.
3. Half-etch features: Corrugations, ribs and boss rings can be half-etched in the same pass, but state the etch depth clearly.
4. Surface finish: Specify passivation, electropolish or bright anneal; surface condition affects sealing and reflectivity.
5. Flatness and handling: Call out flatness per 100 mm and require lint-free handling, since thin foils bend and mark easily.
6. Packaging: Require cleanroom-grade trays or vacuum packaging to protect edges during transit. For custom diaphragm etching, these six points on the drawing reduce back-and-forth.