Stainless Steel FeCl₃+HCl

Chemical Etching Formula
SUS630(17-4PH) with FeCl₃+HCl

For engineers selecting an etching chemistry for SUS630(17-4PH), 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 96.6%, with a typical conveyor speed of 1.23 m/min at 52°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
46 °Bé Concentration
1.430 Specific Gravity
52 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.01-0.5 mm Thickness Range
0.08 mm Typical Thickness
0.12-21.17 m/min Conveyor Speed Range
1.23 m/min Typical Speed
15-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
2-95 μm Undercut Range
2.62 Etch Factor (EF)
96.6% Typical Yield (95.3-97.5%)

Why FeCl₃+HCl for SUS630(17-4PH)?

On SUS630(17-4PH), 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 SUS630(17-4PH) etch line runs a variant of this formula.

Process Window & Bath Control

The process window for this FeCl₃+HCl formula centres on 52°C and 46 °Bé. Conveyor speed spans 0.12-21.17 m/min over the 0.01-0.5 mm thickness band; the typical operating point is 1.23 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

When laying out artwork for SUS630(17-4PH) 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 ~2.62 and undercut range of 2-95 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: 2-95 μm
• Typical etch factor (EF): 2.62

Yield & Production Economics

Typical mass-production yield for SUS630(17-4PH) in the FeCl₃+HCl system is 96.6%, within an observed range of 95.3-97.5%. 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

Typical applications for SUS630(17-4PH) processed with FeCl₃+HCl include precision shims, encoder discs, RF/EMI shields, surgical and dental components, fuel-cell bipolar plates, and fine filter meshes. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

More Stainless Steel Formulas

Other formulas in the same material family.

AM350 Stainless Steel FeCl₃+HCl Through etch (double-sided) SUS2205 Duplex Stainless FeCl₃+HCl Through etch (double-sided) SUS2507 Super Duplex FeCl₃+HCl Through etch (double-sided) SUS301 FeCl₃+HCl Through etch (double-sided) SUS301 FeCl₃+HCl Through etch (double-sided) SUS302 FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

Run the bath at 52°C. Holding much above 57°C can degrade photoresist adhesion and erode feature edges; running below 47°C slows the etch and forces a conveyor-speed reduction. Production lines hold 52°C within ±1.5°C using redundant PID control.

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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