Chemical Etching Formula
SUS316L with FeCl₃+HCl

Formula Summary

The table below summarizes every parameter that defines this etching formula. Values listed as ranges scale with sheet thickness across the supported band.

Why FeCl₃+HCl for SUS316L?

On SUS316L, the ferric chloride system attacks the alloy's oxide layer continuously while ferric ions drive dissolution. It is regenerable, compatible with standard photolithography, and produces clean burr-free edges — which is why nearly every SUS316L etch line runs a variant of this formula.

Process Window & Bath Control

Bath control for SUS316L in FeCl₃+HCl: temperature 50°C, concentration 45 °Bé, specific gravity 1.420. The recipe is tuned for half etch (single-sided). Conveyor speed is the primary throughput control, ranging 44.19 m/min across the supported thickness range. Check specific gravity each shift with a calibrated hydrometer and correct with fresh make-up or water as needed.

Design Rules & Tolerances

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 10 μm and the minimum line width ranges 100 μm across the 0.01 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 1 μm, and the etch factor is about 2.73. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Yield & Production Economics

Typical mass-production yield for SUS316L in the FeCl₃+HCl system is 97.5%, within an observed range of 97.5%. The dominant yield-loss modes are photoresist pinhole defects and rinse-water contamination. Improving incoming sheet quality and photoresist coating consistency gives the highest yield-improvement leverage for this formula.

Typical Applications

Parts produced with the FeCl₃+HCl formula on SUS316L are common in precision shims, encoder discs, RF/EMI shields, surgical and dental components, fuel-cell bipolar plates, and fine filter meshes. The burr-free, stress-free nature of chemical etching makes it the preferred process wherever flatness and edge quality matter more than raw throughput.

Process Equipment & Material Reference

Process equipment for the SUS316L / FeCl₃+HCl combination is built around our wet chemical etching machine platform — closed-loop temperature control, redundant pump headers, and metering for bath replenishment all directly affect the etch factor and yield numbers cited on this page.

The Stainless Steel chemical etching guide reference goes one level above the recipe shown here, surveying the full thickness range, depth options, and common subgrades we run for stainless.

Production Use Cases for This Formula

Parts produced with this SUS316L + FeCl₃+HCl formula end up in a wide range of finished products. Representative production runs we have completed using this exact recipe family include mobile-phone earpiece mesh, stainless steel mesh for aroma diffusers, and stainless filtration mesh for vacuum cleaners. Each case shares the same root sensitivity: clean photoresist edges, a tightly held bath SG of 1.420, and a conveyor speed inside the 44.19 m/min envelope.

Designs that sit slightly outside this thickness or feature-size envelope are usually addressable by a sister formula in the same etchant family. The bath chemistry stays the same; the tuning shifts to conveyor speed and resist choice.

Other Metals Etched with FeCl₃+HCl

The FeCl₃+HCl chemistry is also documented for these alloys.

More Stainless Steel Formulas

Other formulas in the same material family.

Frequently Asked Questions