Aluminum Alloys FeCl₃+HCl

Chemical Etching Formula
Al7050 with FeCl₃+HCl

For engineers selecting an etching chemistry for Al7050, the FeCl₃+HCl formula shown here defines the bath composition, temperature window, and achievable feature sizes across a 0.05-0.5 mm thickness band. Typical mass-production yield for this recipe is 97.5%, with a typical conveyor speed of 0.42 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
0.05-0.5 mm Thickness Range
0.20 mm Typical Thickness
0.12-2.9 m/min Conveyor Speed Range
0.42 m/min Typical Speed
60-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
10-101 μm Undercut Range
2.47 Etch Factor (EF)
97.5% Typical Yield (96.8-97.9%)

Why FeCl₃+HCl for Al7050?

On Al7050, 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 Al7050 etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃+HCl formula centres on 44°C and 36 °Bé. Conveyor speed spans 0.12-2.9 m/min over the 0.05-0.5 mm thickness band; the typical operating point is 0.42 m/min. Every 5°C drop in bath temperature requires roughly a 30% reduction in conveyor speed to hold the same etch depth, so temperature stability is the single biggest lever on consistency.

Design Rules & Tolerances

Design rules for this recipe: hole diameter 60-600 μm, line width 100-500 μm, single-side undercut 10-101 μm — all as a function of thickness across 0.05-0.5 mm. The higher the etch factor (this formula holds about 2.47), 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: 60-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 10-101 μm
• Typical etch factor (EF): 2.47

Yield & Production Economics

Typical mass-production yield for Al7050 in the FeCl₃+HCl system is 97.5%, within an observed range of 96.8-97.9%. 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

Al7050 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

Target specific gravity is 1.310 for this formula. Check it each shift with a calibrated hydrometer. A falling SG indicates the bath is becoming depleted; a rising SG usually points to evaporative water loss that should be corrected with controlled water addition.

Need a Quote for This Process?

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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