Chemical Etching Formula
SUS347
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 SUS347?
On SUS347, 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 SUS347 etch line runs a variant of this formula.
Process Window & Bath Control
Bath control for SUS347 in FeCl₃+HCl: temperature 50°C, concentration 45 °Bé, specific gravity 1.420. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.12-0.95 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
Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 120-600 μm and the minimum line width ranges 100-500 μm across the 0.1-0.5 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 19-93 μm, and the etch factor is about 2.68. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.
• Minimum hole diameter range: 120-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 19-93 μm
• Typical etch factor (EF): 2.68
Yield & Production Economics
This formula delivers a typical yield of 96.4% (range 95.5-96.7%). At that rate, per-part economics are driven mostly by fixed photomask and setup cost for small batches and by sheet utilisation for large runs. The chemistry itself does not change with quantity, so the same recipe serves prototype and production volumes.
Typical Applications
Typical applications for SUS347 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.
Process Equipment & Material Reference
Production of SUS347 parts using the FeCl₃+HCl formula described above runs on a biomedical blade etching machine configured for through etch (double-sided). The bath chemistry, conveyor speed, and rinse cascade detailed on this page reflect the operating profile we use on a live spray-etching line for this alloy.
Related to this formula, the Stainless Steel chemical etching guide page documents the full process envelope for the same alloy family, including pre-treatment chemistry and post-etch inspection criteria.
Production Use Cases for This Formula
Typical end-uses for SUS347 run on this formula include stainless steel mesh for aroma diffusers, stainless steel metal filter mesh, and cold-press juicer filtration mesh. The 50°C bath and 0.1-0.5 mm supported thickness range cover most of the production work in these segments without re-tuning chemistry.
Adjacent applications usually transfer onto this same formula with no chemistry change, sometimes only a conveyor speed tweak. Drop a drawing and a target volume and we will return a process card built off the parameters on this page.
More Stainless Steel Formulas
Other formulas in the same material family.
Frequently Asked Questions
Sources & References
- ASTM E407: Standard Practice for Microetching Metals and Alloys
- ASTM B912: Standard Specification for Passivation of Stainless Steels
- Photo Chemical Machining Institute — process capability guidelines
- NIST Engineering Statistics Handbook — process tolerance and capability
Standards are referenced for context. Always confirm parameters against the current published edition and your own process validation.
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.