Indium Chemical Etching — Engineering Reference
Wet chemical etching of Indium is a precision subtractive process that defines fine features by selectively dissolving the metal through a photoresist-patterned mask. On Indium specifically, the etchant choice, bath temperature, and conveyor speed combine to set the etch factor, undercut, and yield envelope every production run lives in.
Why Wet Chemical Etching for Indium?
Compared to laser, stamping, or wire EDM, wet chemical etching imparts no mechanical or thermal load to Indium. The process is parallel — every feature on a sheet etches simultaneously — so feature count has no impact on tooling cost. For Indium parts with hundreds or thousands of micro-features per piece, that is the dominant economic argument.
- Burr-free, stress-free edges — no post-deburring on Indium required.
- Tooling cost flat with feature complexity — only the photomask changes.
- Fast prototype iteration — artwork edits, not tool re-cuts.
- Tight tolerance on thin gauge Indium (down to ±25 μm in production).
- Compatible with downstream passivation, plating, electropolishing.
Process Window for Indium
Production lines etching Indium run a closed-loop temperature band of typically ±1.5 °C, with bath specific gravity monitored each shift via hydrometer or refractometer. Conveyor speed inversely tracks sheet thickness: thinner stock runs faster, thicker stock slower, with the goal of holding etch factor (EF) above 2.5 and single-side undercut below thirty microns wherever possible. For Indium, the recommended chemistry is HCl(15%)+H₂SO₄(5%).
| Recommended etchant | HCl(15%)+H₂SO₄(5%) |
|---|---|
| Bath temperature window | 40 – 55 °C (chemistry-dependent) |
| Specific gravity setpoint | 1.30 – 1.45 g/cm³ for ferric chloride systems |
| Conveyor speed range | 0.4 – 8.0 m/min (thickness-dependent) |
| Typical etch factor (EF) | 2.5 – 3.0 |
| Single-side undercut | 5 – 40 μm depending on depth and thickness |
| Minimum hole diameter | ≈ 1.2× sheet thickness |
| Minimum line width | ≈ 1.0× sheet thickness |
| Mass-production yield | 95 – 99% on mature recipes for Indium |
Common Applications for Chemically Etched Indium
Across the markets we serve, chemically etched Indium is most often deployed in filtration meshes, lead frames and connector blanks, surgical and consumer blades, EMI shielding gaskets, heat-dissipation vents, and decorative architectural pieces. Thickness and feature complexity push different applications onto different recipes.
Related Recipes & Process Parameters
Every formula and parameter row below is a live page on this site with the full chemistry, conveyor speed, and tolerance window for the exact material-thickness-etchant combination. These are the references our process engineers cite from on production shifts.
Related Material References
Related Production Applications
Related Process Equipment
Frequently Asked Questions
What thickness range is supported for Indium?
Production runs on Indium typically cover 0.02 mm to 2.0 mm sheet stock. Different thicknesses use the same chemistry; only conveyor speed and feature tolerances change.
Which etchant works best for Indium?
The recommended starting chemistry is HCl(15%)+H₂SO₄(5%). It balances etch rate, bath stability, and photoresist compatibility for Indium across the production thickness range.
What is the minimum feature size on Indium?
As a working rule, the minimum hole diameter scales as 1.2× sheet thickness and minimum line width as ~1.0× thickness for Indium. At the fine end, photoresist resolution becomes the limiting factor — not the etchant.
Is Indium chemical etching suitable for medical or aerospace parts?
Yes. The process produces stress-free, burr-free parts with no recast layer — exactly the surface condition required by medical, aerospace, and high-reliability applications using Indium.
Frequently Asked Questions
What is Wet Chemical Etching Indium and how is it made?
Wet Chemical Etching Indium is produced by photochemical etching — a process that uses a patterned resist and etchant to remove metal precisely, with no mechanical stress or burrs.
What tolerances can you achieve for Wet Chemical Etching Indium?
Photochemical etching holds tight, repeatable tolerances on thin metal, which makes it well suited to Wet Chemical Etching Indium. Exact figures depend on material and thickness.
Can Wet Chemical Etching Indium be customised to my drawing?
Yes. Wet Chemical Etching Indium is made to order from your CAD/artwork, so dimensions, features and material are all tailored to your specification.