Chemical Etching Formula
C1100 T2 copper
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 C1100 T2 copper?
Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like C1100 T2 copper. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on C1100 T2 copper is anisotropic etching with predictable undercut and an easily regenerated spent bath.
Process Window & Bath Control
The process window for this FeCl₃ formula centres on 44°C and 34 °Bé. Conveyor speed spans 18.51-66.76 m/min over the 0.01-0.02 mm thickness band; the typical operating point is 32.65 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
Design rules for this recipe: hole diameter 46252 μm, line width 100 μm, single-side undercut 46025 μm — all as a function of thickness across 0.01-0.02 mm. The higher the etch factor (this formula holds about 2.88), the tighter the achievable tolerance. Below the minimum feature sizes, yield falls off steeply, so treat those numbers as hard floors rather than targets.
• Minimum hole diameter range: 46252 μm
• Minimum line width range: 100 μm
• Single-side undercut range: 46025 μm
• Typical etch factor (EF): 2.88
Yield & Production Economics
Typical mass-production yield for C1100 T2 copper in the FeCl₃ system is 99.0%, within an observed range of 99%. 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
Typical applications for C1100 T2 copper processed with FeCl₃ include lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. 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 C1100 T2 copper parts using the FeCl₃ formula described above runs on a plasma surface treatment 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 Copper 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 C1100 T2 copper run on this formula include custom thin-film heating elements, soy-milk-maker filtration mesh, and high-precision etched lead frames. The 44°C bath and 0.01-0.02 mm supported thickness range cover most of the production work in these segments without re-tuning chemistry.
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.
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.