Copper & Brass FeCl₃

Chemical Etching Formula
C2680 brass with FeCl₃

This page documents the reference wet chemical etching formula for C2680 brass using the FeCl₃ system. The recipe below covers a sheet-thickness range of 0.05-0.5 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
38 °Bé Concentration
1.360 Specific Gravity
44 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.05-0.5 mm Thickness Range
0.18 mm Typical Thickness
0.12-3.11 m/min Conveyor Speed Range
0.56 m/min Typical Speed
60-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
9-90 μm Undercut Range
2.79 Etch Factor (EF)
97.8% Typical Yield (97-98.1%)

Why FeCl₃ for C2680 brass?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like C2680 brass. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on C2680 brass is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Hold the bath at 44°C with concentration 38 °Bé (specific gravity 1.360). Across the 0.05-0.5 mm thickness range, conveyor speed runs from 0.12-3.11 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.56 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

When laying out artwork for C2680 brass at through etch (double-sided), plan for a minimum hole diameter in the 60-600 μm range and a minimum line width in the 100-500 μm range, depending on the chosen sheet thickness within 0.05-0.5 mm. The etch factor of ~2.79 and undercut range of 9-90 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 60-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 9-90 μm
• Typical etch factor (EF): 2.79

Yield & Production Economics

This formula delivers a typical yield of 97.8% (range 97-98.1%). 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 C2680 brass 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

Standard pre-treatment is degrease, micro-etch to activate the surface, rinse, photoresist lamination or coating, UV exposure through the artwork, and develop. Pre-treatment quality directly drives yield for C2680 brass: poor degreasing causes resist adhesion failures that show up as random pinhole defects in the etched pattern.

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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