Copper & Brass FeCl₃

Chemical Etching Formula
C1020 OF Copper with FeCl₃

This page documents the reference wet chemical etching formula for C1020 OF Copper using the FeCl₃ 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 Etchant System
36 °Bé Concentration
1.340 Specific Gravity
46 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.05-0.3 mm Thickness Range
0.15 mm Typical Thickness
0.26-3.22 m/min Conveyor Speed Range
0.84 m/min Typical Speed
60-360 μm Min Hole Ø Range
100-300 μm Min Line Width Range
9-53 μm Undercut Range
2.83 Etch Factor (EF)
98.1% Typical Yield (97.8-98.4%)

Why FeCl₃ for C1020 OF Copper?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like C1020 OF Copper. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on C1020 OF Copper is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Hold the bath at 46°C with concentration 36 °Bé (specific gravity 1.340). Across the 0.05-0.3 mm thickness range, conveyor speed runs from 0.26-3.22 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.84 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

Design rules for this recipe: hole diameter 60-360 μm, line width 100-300 μm, single-side undercut 9-53 μm — all as a function of thickness across 0.05-0.3 mm. The higher the etch factor (this formula holds about 2.83), 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: 60-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 9-53 μm
• Typical etch factor (EF): 2.83

Yield & Production Economics

Expect a yield in the 97.8-98.4% range for C1020 OF Copper with FeCl₃, with 98.1% 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

C1020 OF Copper etched with this recipe typically ends up in lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. 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 Copper & Brass Formulas

Other formulas in the same material family.

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) C1100 T2 copper FeCl₃ Half etch (single-sided)

Frequently Asked Questions

Typical inspection on C1020 OF Copper etched with FeCl₃ includes optical checks for unetched residue and surface defects, dimensional metrology on critical features, and edge-quality assessment. Final dimensional tolerance is usually ±10% of the smallest critical feature or ±25 μm, whichever is larger.

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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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