Stainless Steel FeCl₃+HCl

Chemical Etching Formula
AM350 Stainless Steel with FeCl₃+HCl

This page documents the reference wet chemical etching formula for AM350 Stainless Steel using the FeCl₃+HCl system. The recipe below covers a sheet-thickness range of 0.1-0.3 mm and is configured for through etch (double-sided). Every value is drawn from operational process records rather than theoretical calculation, and is provided as a starting point for your own process development.

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
46 °Bé Concentration
1.430 Specific Gravity
54 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.1-0.3 mm Thickness Range
0.20 mm Typical Thickness
0.16-0.82 m/min Conveyor Speed Range
0.29 m/min Typical Speed
120-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
20-59 μm Undercut Range
2.55 Etch Factor (EF)
95.6% Typical Yield (95.3-95.9%)

Why FeCl₃+HCl for AM350 Stainless Steel?

On AM350 Stainless Steel, 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 AM350 Stainless Steel etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃+HCl formula centres on 54°C and 46 °Bé. Conveyor speed spans 0.16-0.82 m/min over the 0.1-0.3 mm thickness band; the typical operating point is 0.29 m/min. Every 5°C drop in bath temperature requires roughly a 30% reduction in conveyor speed to hold the same etch depth, so temperature stability is the single biggest lever on consistency.

Design Rules & Tolerances

When laying out artwork for AM350 Stainless Steel at through etch (double-sided), plan for a minimum hole diameter in the 120-360 μm range and a minimum line width in the 100-300 μm range, depending on the chosen sheet thickness within 0.1-0.3 mm. The etch factor of ~2.55 and undercut range of 20-59 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 120-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 20-59 μm
• Typical etch factor (EF): 2.55

Yield & Production Economics

This formula delivers a typical yield of 95.6% (range 95.3-95.9%). 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

AM350 Stainless Steel 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.

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) SUS303 FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Run the bath at 54°C. Holding much above 59°C can degrade photoresist adhesion and erode feature edges; running below 49°C slows the etch and forces a conveyor-speed reduction. Production lines hold 54°C within ±1.5°C using redundant PID control.

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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