Copper & Brass FeCl₃

Chemical Etching Formula
H62 brass with FeCl₃

The FeCl₃ chemistry is a proven formula for H62 brass. This reference sheet lists the concentration (38 °Bé), specific gravity (1.360), bath temperature (44°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 Etchant System
38 °Bé Concentration
1.360 Specific Gravity
44 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.5 mm Thickness Range
0.14 mm Typical Thickness
0.12-22.96 m/min Conveyor Speed Range
0.79 m/min Typical Speed
15-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
2-90 μm Undercut Range
2.78 Etch Factor (EF)
97.9% Typical Yield (97-98.2%)

Why FeCl₃ for H62 brass?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like H62 brass. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on H62 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 0.01-0.5 mm thickness range, conveyor speed runs from 0.12-22.96 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.79 m/min for 0.14 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

Design rules for this recipe: hole diameter 15-600 μm, line width 100-500 μm, single-side undercut 2-90 μm — all as a function of thickness across 0.01-0.5 mm. The higher the etch factor (this formula holds about 2.78), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.

Design Rule Summary
• Minimum hole diameter range: 15-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 2-90 μm
• Typical etch factor (EF): 2.78

Yield & Production Economics

Typical mass-production yield for H62 brass in the FeCl₃ system is 97.9%, within an observed range of 97-98.2%. 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

Parts produced with the FeCl₃ formula on H62 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

Spent FeCl₃ bath contains dissolved H62 brass ions and depleted oxidizer. Standard practice is chemical or electrolytic regeneration to recover activity, plus periodic decanting of metal-rich sludge for off-site recovery. Treatment to neutral pH with metals precipitation is the minimum before any discharge, and requirements vary by jurisdiction.

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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