Chemical Etching Formula
SUS301
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 SUS301?
On SUS301, 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 SUS301 etch line runs a variant of this formula.
Process Window & Bath Control
Bath control for SUS301 in FeCl₃+HCl: temperature 48°C, concentration 44 °Bé, specific gravity 1.410. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.21-6.57 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 SUS301 at through etch (double-sided), plan for a minimum hole diameter in the 36-360 μm range and a minimum line width in the 100-300 μm range, depending on the chosen sheet thickness within 0.03-0.3 mm. The etch factor of ~2.81 and undercut range of 5-53 μm determine how much the mask must be biased to land the finished dimension on target.
• Minimum hole diameter range: 36-360 μm
• Minimum line width range: 100-300 μm
• Single-side undercut range: 5-53 μm
• Typical etch factor (EF): 2.81
Yield & Production Economics
Expect a yield in the 97-97.8% range for SUS301 with FeCl₃+HCl, with 97.6% 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
Typical applications for SUS301 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
On the shop floor, this SUS301 + FeCl₃+HCl recipe is implemented on a wet chemical etching machine. The 48°C bath setpoint and 0.21-6.57 m/min conveyor range correspond to verified production envelopes on that equipment for through etch (double-sided).
The Stainless Steel chemical etching guide reference goes one level above the recipe shown here, surveying the full thickness range, depth options, and common subgrades we run for stainless.
Production Use Cases for This Formula
Production examples for the SUS301 / FeCl₃+HCl recipe span cold-press juicer filtration mesh, stainless steel shower-head filter mesh, and stainless steel mesh for aroma diffusers. In every case, the etch factor and undercut figures on this page are the dominant tolerance drivers — bath maintenance discipline matters more than equipment headline rating.
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.