Copper & Brass FeCl₃+HCl

Chemical Etching Formula
C17200 beryllium copper with FeCl₃+HCl

This page documents the reference wet chemical etching formula for C17200 beryllium copper using the FeCl₃+HCl system. The recipe below covers a sheet-thickness range of 0.05-0.3 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
42 °Bé Concentration
1.390 Specific Gravity
48 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.05-0.3 mm Thickness Range
0.15 mm Typical Thickness
0.19-2.77 m/min Conveyor Speed Range
0.67 m/min Typical Speed
60-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
9-54 μm Undercut Range
2.80 Etch Factor (EF)
97.2% Typical Yield (96.8-97.5%)

Why FeCl₃+HCl for C17200 beryllium copper?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like C17200 beryllium copper. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on C17200 beryllium copper is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Hold the bath at 48°C with concentration 42 °Bé (specific gravity 1.390). Across the 0.05-0.3 mm thickness range, conveyor speed runs from 0.19-2.77 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.67 m/min for 0.15 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 60-360 μm and the minimum line width ranges 100-300 μm across the 0.05-0.3 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 9-54 μm, and the etch factor is about 2.80. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Design Rule Summary
• Minimum hole diameter range: 60-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 9-54 μm
• Typical etch factor (EF): 2.80

Yield & Production Economics

Expect a yield in the 96.8-97.5% range for C17200 beryllium copper with FeCl₃+HCl, with 97.2% typical on a well-controlled line. Most rejects trace back to upstream coating and exposure rather than to the etch bath itself, so tightening photolithography control is usually the fastest path to a higher number.

Typical Applications

Typical applications for C17200 beryllium copper processed with FeCl₃+HCl include lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

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

This formula is documented for a sheet-thickness range of 0.05-0.3 mm, with a typical value of 0.15 mm. Outside this band the same chemistry may still work, but conveyor speed and feature tolerances should be re-verified with a sample run before production.

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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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