Copper & Brass FeCl₃

Chemical Etching Formula
C197 Copper-Iron Alloy with FeCl₃

This page documents the reference wet chemical etching formula for C197 Copper-Iron Alloy using the FeCl₃ 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 Etchant System
36 °Bé Concentration
1.340 Specific Gravity
46 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.1-0.3 mm Thickness Range
0.20 mm Typical Thickness
0.25-1.15 m/min Conveyor Speed Range
0.44 m/min Typical Speed
120-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
18-54 μm Undercut Range
2.78 Etch Factor (EF)
97.5% Typical Yield (97.2-97.8%)

Why FeCl₃ for C197 Copper-Iron Alloy?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like C197 Copper-Iron Alloy. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on C197 Copper-Iron Alloy is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

The process window for this FeCl₃ formula centres on 46°C and 36 °Bé. Conveyor speed spans 0.25-1.15 m/min over the 0.1-0.3 mm thickness band; the typical operating point is 0.44 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 C197 Copper-Iron Alloy 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 ~2.78 and undercut range of 18-54 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: 18-54 μm
• Typical etch factor (EF): 2.78

Yield & Production Economics

This formula delivers a typical yield of 97.5% (range 97.2-97.8%). 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

Parts produced with the FeCl₃ formula on C197 Copper-Iron Alloy are common in lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. The burr-free, stress-free nature of chemical etching makes it the preferred process wherever flatness and edge quality matter more than raw throughput.

More Copper & Brass Formulas

Other formulas in the same material family.

C1020 OF Copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Half etch (single-sided)

Frequently Asked Questions

Yes. The FeCl₃ chemistry and 46°C bath are identical from a single prototype part up to full production — the chemistry does not depend on quantity. Conveyor speed stays in the 0.25-1.15 m/min range. Only the per-part economics shift, since fixed photomask and setup costs dominate at low volumes.

Need a Quote for This Process?

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

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