Chemical Etching Formula
H65 brass
with FeCl₃
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 for H65 brass?
On H65 brass, 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 H65 brass etch line runs a variant of this formula.
Process Window & Bath Control
The process window for this FeCl₃ formula centres on 43°C and 36 °Bé. Conveyor speed spans 5.22-23.35 m/min over the 0.01-0.04 mm thickness band; the typical operating point is 10.80 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 H65 brass at through etch (double-sided), plan for a minimum hole diameter in the 15-42 μm range and a minimum line width in the 100 μm range, depending on the chosen sheet thickness within 0.01-0.04 mm. The etch factor of ~2.82 and undercut range of 46059 μm determine how much the mask must be biased to land the finished dimension on target.
• Minimum hole diameter range: 15-42 μm
• Minimum line width range: 100 μm
• Single-side undercut range: 46059 μm
• Typical etch factor (EF): 2.82
Yield & Production Economics
Typical mass-production yield for H65 brass in the FeCl₃ system is 98.8%, within an observed range of 98.8%. 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
H65 brass etched with this recipe typically ends up in lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. 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.
Process Equipment & Material Reference
Production of H65 brass parts using the FeCl₃ formula described above runs on a wet chemical 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 Brass 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 H65 brass run on this formula include tea-infuser custom filter etching, cold-press juicer filtration mesh, and ultrasonic mesh for robotic vacuum cleaners. The 43°C bath and 0.01-0.04 mm supported thickness range cover most of the production work in these segments without re-tuning chemistry.
Designs that sit slightly outside this thickness or feature-size envelope are usually addressable by a sister formula in the same etchant family. The bath chemistry stays the same; the tuning shifts to conveyor speed and resist choice.
More Copper & Brass 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 chemistry. Send us your part drawing and quantity for a full process quote.