Chemical Etching Formula
SPCC Cold-Rolled Steel
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 SPCC Cold-Rolled Steel?
Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like SPCC Cold-Rolled Steel. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on SPCC Cold-Rolled Steel is anisotropic etching with predictable undercut and an easily regenerated spent bath.
Process Window & Bath Control
Hold the bath at 46°C with concentration 42 °Bé (specific gravity 1.390). Across the 0.01 mm thickness range, conveyor speed runs from 36.37 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 36.37 m/min for 0.01 mm stock. Use redundant PID temperature control to hold the bath within ±1.5°C, and titrate at least once per shift.
Design Rules & Tolerances
Design rules for this recipe: hole diameter 12 μm, line width 100 μm, single-side undercut 2 μm — all as a function of thickness across 0.01 mm. The higher the etch factor (this formula holds about 2.75), 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: 12 μm
• Minimum line width range: 100 μm
• Single-side undercut range: 2 μm
• Typical etch factor (EF): 2.75
Yield & Production Economics
Typical mass-production yield for SPCC Cold-Rolled Steel in the FeCl₃ system is 97.6%, within an observed range of 97.6%. 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
SPCC Cold-Rolled Steel etched with this recipe typically ends up in spring elements, blades, shim stock, and stamped-replacement flat parts. 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.
More Carbon & Tool Steel Formulas
Other formulas in the same material family.
Frequently Asked Questions
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.