Chemical Etching Formula
DT4 pure iron with FeCl₃+HCl

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.

Why FeCl₃+HCl for DT4 pure iron?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like DT4 pure iron. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on DT4 pure iron is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Bath control for DT4 pure iron in FeCl₃+HCl: temperature 46°C, concentration 40 °Bé, specific gravity 1.380. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.19-2.77 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 DT4 pure iron at through etch (double-sided), plan for a minimum hole diameter in the 60-360 μm range and a minimum line width in the 100-300 μm range, depending on the chosen sheet thickness within 0.05-0.3 mm. The etch factor of ~2.80 and undercut range of 9-54 μm determine how much the mask must be biased to land the finished dimension on target.

Yield & Production Economics

Typical mass-production yield for DT4 pure iron in the FeCl₃+HCl system is 96.6%, within an observed range of 96.1-96.8%. 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

Parts produced with the FeCl₃+HCl formula on DT4 pure iron are common in spring elements, blades, shim stock, and stamped-replacement flat parts. The burr-free, stress-free nature of chemical etching makes it the preferred process wherever flatness and edge quality matter more than raw throughput.

Process Equipment & Material Reference

This DT4 pure iron formula is part of the standard process library running on our wet chemical etching machine. The same chemistry can be ported to any horizontal spray-etching line of comparable nozzle layout and bath-titration discipline.

For a broader treatment of the material itself — alloy variants, surface preparation, and process limits across thickness ranges — see our Steel chemical etching guide. That overview complements the formula-specific bath and conveyor data on this page.

Production Use Cases for This Formula

Parts produced with this DT4 pure iron + FeCl₃+HCl formula end up in a wide range of finished products. Representative production runs we have completed using this exact recipe family include soy-milk-maker filtration mesh, high-speed air-intake mesh for hair dryers, and cold-press juicer filtration mesh. Each case shares the same root sensitivity: clean photoresist edges, a tightly held bath SG of 1.380, and a conveyor speed inside the 0.19-2.77 m/min envelope.

If your part falls into one of these classes — or a closely adjacent one — this formula is usually the right starting point. We confirm fit with a short sample run on the actual sheet stock before locking in mask artwork.

Other Metals Etched with FeCl₃+HCl

The FeCl₃+HCl chemistry is also documented for these alloys.

More Carbon & Tool Steel Formulas

Other formulas in the same material family.

Frequently Asked Questions