Chemical Etching Formula
SUS420J2 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 SUS420J2?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like SUS420J2. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on SUS420J2 is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Bath control for SUS420J2 in FeCl₃+HCl: temperature 50°C, concentration 44 °Bé, specific gravity 1.410. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.12-1.08 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 120-600 μm and the minimum line width ranges 100-500 μm across the 0.1-0.5 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 18-91 μm, and the etch factor is about 2.75. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Yield & Production Economics

Typical mass-production yield for SUS420J2 in the FeCl₃+HCl system is 96.7%, within an observed range of 95.9-97.1%. 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

SUS420J2 etched with this recipe typically ends up in precision shims, encoder discs, RF/EMI shields, surgical and dental components, fuel-cell bipolar plates, and fine filter meshes. Because chemical etching applies no mechanical or thermal load, the finished features are free of work-hardening and heat-affected zones — a decisive advantage over stamping or laser cutting for these uses.

Process Equipment & Material Reference

On the shop floor, this SUS420J2 + FeCl₃+HCl recipe is implemented on a wet chemical etching machine. The 50°C bath setpoint and 0.12-1.08 m/min conveyor range correspond to verified production envelopes on that equipment for through etch (double-sided).

If you need a wider view of stainless beyond this single recipe, our Stainless Steel chemical etching guide covers grade selection, photoresist compatibility, and typical industries that consume this metal in etched form.

Production Use Cases for This Formula

Typical end-uses for SUS420J2 run on this formula include stainless steel metal filter mesh, stainless steel mesh for aroma diffusers, and stainless filtration mesh for vacuum cleaners. The 50°C bath and 0.1-0.5 mm supported thickness range cover most of the production work in these segments without re-tuning chemistry.

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