Aluminum Alloys FeCl₃+HCl

Chemical Etching Formula
Al6061 with FeCl₃+HCl

This reference describes how Al6061 responds to the FeCl₃+HCl etching formula. At a bath temperature of 42°C and concentration of 34 °Bé, the recipe holds an etch factor of about 2.52 and a typical production yield of 97.8%. It is intended as engineering reference data for design, sourcing, and process planning.

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
34 °Bé Concentration
1.290 Specific Gravity
42 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.5 mm Thickness Range
0.08 mm Typical Thickness
0.12-73.48 m/min Conveyor Speed Range
1.50 m/min Typical Speed
8-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
1-99 μm Undercut Range
2.52 Etch Factor (EF)
97.8% Typical Yield (96.8-98%)

Why FeCl₃+HCl for Al6061?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like Al6061. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on Al6061 is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Hold the bath at 42°C with concentration 34 °Bé (specific gravity 1.290). Across the 0.01-0.5 mm thickness range, conveyor speed runs from 0.12-73.48 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 1.50 m/min for 0.08 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 Al6061 at through etch (double-sided), plan for a minimum hole diameter in the 8-600 μm range and a minimum line width in the 100-500 μm range, depending on the chosen sheet thickness within 0.01-0.5 mm. The etch factor of ~2.52 and undercut range of 1-99 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 8-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 1-99 μm
• Typical etch factor (EF): 2.52

Yield & Production Economics

Expect a yield in the 96.8-98% range for Al6061 with FeCl₃+HCl, with 97.8% 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 Al6061 processed with FeCl₃+HCl include lightweight RF shields, heat-spreader masks, nameplates, decorative trim, and lightweight structural lattices. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

More Aluminum Alloys Formulas

Other formulas in the same material family.

Al1060 FeCl₃+HCl Through etch (double-sided) Al1060 FeCl₃+HCl Through etch (double-sided) Al1100 FeCl₃+HCl Through etch (double-sided) Al2014 FeCl₃+HCl Through etch (double-sided) Al2017 FeCl₃+HCl Through etch (double-sided) Al2024 FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Spent FeCl₃+HCl bath contains dissolved Al6061 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.

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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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