Stainless Steel FeCl₃+HCl

Chemical Etching Formula
SUS316 with FeCl₃+HCl

The FeCl₃+HCl chemistry is a proven formula for SUS316. This reference sheet lists the concentration (45 °Bé), specific gravity (1.420), bath temperature (50°C), and the full range of conveyor speeds and feature tolerances that result. Use it to size your process before committing to a production trial.

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.

FeCl₃+HCl Etchant System
45 °Bé Concentration
1.420 Specific Gravity
50 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.03-0.5 mm Thickness Range
0.18 mm Typical Thickness
0.12-6.09 m/min Conveyor Speed Range
0.45 m/min Typical Speed
36-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
6-92 μm Undercut Range
2.72 Etch Factor (EF)
97.0% Typical Yield (96-97.4%)

Why FeCl₃+HCl for SUS316?

On SUS316, 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 SUS316 etch line runs a variant of this formula.

Process Window & Bath Control

Hold the bath at 50°C with concentration 45 °Bé (specific gravity 1.420). Across the 0.03-0.5 mm thickness range, conveyor speed runs from 0.12-6.09 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.45 m/min for 0.18 mm stock. Use redundant PID temperature control to hold the bath within ±1.5°C, and titrate at least once per shift.

Design Rules & Tolerances

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 36-600 μm and the minimum line width ranges 100-500 μm across the 0.03-0.5 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 6-92 μm, and the etch factor is about 2.72. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Design Rule Summary
• Minimum hole diameter range: 36-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 6-92 μm
• Typical etch factor (EF): 2.72

Yield & Production Economics

This formula delivers a typical yield of 97.0% (range 96-97.4%). At that rate, per-part economics are driven mostly by fixed photomask and setup cost for small batches and by sheet utilisation for large runs. The chemistry itself does not change with quantity, so the same recipe serves prototype and production volumes.

Typical Applications

SUS316 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.

More Stainless Steel Formulas

Other formulas in the same material family.

AM350 Stainless Steel FeCl₃+HCl Through etch (double-sided) SUS2205 Duplex Stainless FeCl₃+HCl Through etch (double-sided) SUS2507 Super Duplex FeCl₃+HCl Through etch (double-sided) SUS301 FeCl₃+HCl Through etch (double-sided) SUS301 FeCl₃+HCl Through etch (double-sided) SUS302 FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Typical mass-production yield is 97.0%, within an observed range of 96-97.4%. The leading yield-loss modes are photoresist pinhole defects and rinse contamination, so the fastest route to a higher number is tighter incoming-sheet and coating control rather than changes to the etch bath.

Need a Quote for This Process?

WET Etched runs production wet chemical etching lines using the FeCl₃+HCl chemistry. Send us your part drawing and quantity for a full process quote.

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