Aluminum Alloys FeCl₃+HCl

Chemical Etching Formula
Al7075 with FeCl₃+HCl

For engineers selecting an etching chemistry for Al7075, the FeCl₃+HCl formula shown here defines the bath composition, temperature window, and achievable feature sizes across a 0.01-0.5 mm thickness band. Typical mass-production yield for this recipe is 97.7%, with a typical conveyor speed of 0.85 m/min at 44°C.

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
36 °Bé Concentration
1.310 Specific Gravity
44 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.5 mm Thickness Range
0.12 mm Typical Thickness
0.12-21.41 m/min Conveyor Speed Range
0.85 m/min Typical Speed
15-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
2-101 μm Undercut Range
2.48 Etch Factor (EF)
97.7% Typical Yield (96.8-98%)

Why FeCl₃+HCl for Al7075?

On Al7075, the ferric chloride system attacks the alloy's oxide layer continuously while ferric ions drive dissolution. It is regenerable, compatible with standard photolithography, and produces clean burr-free edges — which is why nearly every Al7075 etch line runs a variant of this formula.

Process Window & Bath Control

Bath control for Al7075 in FeCl₃+HCl: temperature 44°C, concentration 36 °Bé, specific gravity 1.310. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.12-21.41 m/min across the supported thickness range. Check specific gravity each shift with a calibrated hydrometer and correct with fresh make-up or water as needed.

Design Rules & Tolerances

When laying out artwork for Al7075 at through etch (double-sided), plan for a minimum hole diameter in the 15-600 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 ~2.48 and undercut range of 2-101 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 15-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 2-101 μm
• Typical etch factor (EF): 2.48

Yield & Production Economics

Expect a yield in the 96.8-98% range for Al7075 with FeCl₃+HCl, with 97.7% 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

Al7075 etched with this recipe typically ends up in lightweight RF shields, heat-spreader masks, nameplates, decorative trim, and lightweight structural lattices. 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 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

The recommended working concentration for Al7075 in the FeCl₃+HCl system is 36 °Bé, corresponding to a specific gravity of about 1.310. Titrate the bath at least once per shift and correct back toward this setpoint; drift below it signals depletion, while drift above usually means evaporative water loss.

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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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