Chemical Etching Formula
QSn6.5 Tin Bronze 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 QSn6.5 Tin Bronze?

On QSn6.5 Tin Bronze, 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 QSn6.5 Tin Bronze etch line runs a variant of this formula.

Process Window & Bath Control

Hold the bath at 46°C with concentration 40 °Bé (specific gravity 1.380). Across the 0.05-0.3 mm thickness range, conveyor speed runs from 0.21-2.64 m/min — thinner sheets move faster, thicker sheets slower, in roughly inverse proportion to thickness. A typical mid-range setpoint is 0.69 m/min for 0.15 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

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 60-360 μm and the minimum line width ranges 100-300 μm across the 0.05-0.3 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 9-55 μm, and the etch factor is about 2.72. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Yield & Production Economics

This formula delivers a typical yield of 97.4% (range 97-97.7%). 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

QSn6.5 Tin Bronze 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 QSn6.5 Tin Bronze 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 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 QSn6.5 Tin Bronze run on this formula include tea-infuser custom filter etching, stainless steel metal filter mesh, and ultrasonic mesh for robotic vacuum cleaners. The 46°C bath and 0.05-0.3 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.

Other Metals Etched with FeCl₃

The FeCl₃ chemistry is also documented for these alloys.

More Copper & Brass Formulas

Other formulas in the same material family.

Frequently Asked Questions