Carbon & Tool Steel FeCl₃+HCl

Chemical Etching Formula
SKD11 Cold-Work Die Steel with FeCl₃+HCl

This reference describes how SKD11 Cold-Work Die Steel responds to the FeCl₃+HCl etching formula. At a bath temperature of 52°C and concentration of 46 °Bé, the recipe holds an etch factor of about 2.60 and a typical production yield of 96.3%. 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
46 °Bé Concentration
1.430 Specific Gravity
52 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.1-0.5 mm Thickness Range
0.25 mm Typical Thickness
0.12-0.98 m/min Conveyor Speed Range
0.27 m/min Typical Speed
120-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
19-96 μm Undercut Range
2.60 Etch Factor (EF)
96.3% Typical Yield (95.5-96.7%)

Why FeCl₃+HCl for SKD11 Cold-Work Die Steel?

On SKD11 Cold-Work Die Steel, 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 SKD11 Cold-Work Die Steel 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 0.12-0.98 m/min over the 0.1-0.5 mm thickness band; the typical operating point is 0.27 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 SKD11 Cold-Work Die Steel at through etch (double-sided), plan for a minimum hole diameter in the 120-600 μm range and a minimum line width in the 100-500 μm range, depending on the chosen sheet thickness within 0.1-0.5 mm. The etch factor of ~2.60 and undercut range of 19-96 μm determine how much the mask must be biased to land the finished dimension on target.

Design Rule Summary
• Minimum hole diameter range: 120-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 19-96 μm
• Typical etch factor (EF): 2.60

Yield & Production Economics

Expect a yield in the 95.5-96.7% range for SKD11 Cold-Work Die Steel with FeCl₃+HCl, with 96.3% 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

SKD11 Cold-Work Die Steel etched with this recipe typically ends up in spring elements, blades, shim stock, and stamped-replacement flat parts. 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 Carbon & Tool Steel Formulas

Other formulas in the same material family.

50CrV4 Spring Steel FeCl₃+HCl Through etch (double-sided) 65Mn Spring Steel FeCl₃+HCl Through etch (double-sided) 65Mn Spring Steel FeCl₃+HCl Half etch (single-sided) DT4 pure iron FeCl₃+HCl Through etch (double-sided) SK2 Tool Steel FeCl₃+HCl Through etch (double-sided) SK3 Tool Steel FeCl₃+HCl Through etch (double-sided)

Frequently Asked Questions

This recipe is configured for through etch (double-sided). The 52°C bath, 46 °Bé concentration, and 0.12-0.98 m/min conveyor-speed range are tuned for that depth type. Switching between through-etch and half-etch, or single- versus double-sided, requires re-tuning conveyor speed and may change the mask design.

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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