Electrochemical Etching: Thickness, Specs & Materials

What is Electrochemical etch?

It is commonly used for logos, lot codes, serials, and identification on finished metal tools and components.

How it works

A stencil carrying the artwork is placed on the conductive part and wetted with an electrolyte matched to the alloy. An electrode pad applies controlled current through the open stencil. Direct current removes a shallow layer for an etched mark; alternating-current recipes can form a dark oxide contrast on selected alloys. The surface is then neutralized, rinsed, and dried. Voltage, waveform, dwell, pad pressure, electrolyte, and surface finish control depth and contrast.

Why specify it

Marks hardened or finished conductive metals without cutting force
Typical depth is about 2–25 µm
Portable equipment reaches large assembled parts
Reusable stencils support repeated fixed artwork

Where it falls short

Only electrically conductive substrates can be etched
Electrolyte and neutralizer must match the alloy
Variable data generally requires a new stencil or digital stencil system
Poor rinsing can stain or initiate corrosion

Electrochemical etch at a glance

Electrochemical etch is a middle-of-the-range finish; its best score is cosmetic quality (55 of 100), at a standard cost. It adds little corrosion protection or lubricity. Surface hardness is not rated: the finish leaves the part's own surface.

Corrosion protectionMinimal0 / 100

Surface hardnessNot rated—

Cosmetic qualityGood55 / 100

LubricityMinimal10 / 100

Relative costStandard24 / 100

Each score is 0–100 against every finish in this catalog. Corrosion comes from salt-spray life (ASTM B117, log scale) and hardness from the finish layer's Vickers or pencil hardness; cosmetic, lubricity and cost are FabDigit's engineering assessment. Economy on the radar is the inverse of cost.

Electrochemical etch key numbers

Typical values from the governing specifications and shop practice; bars are this finish against the highest value among marking & decoration finishes.

Thickness2–25 µm0.08–0.98 mil

Thickness

2–25 µm recessed electrochemical mark depth; dark oxide marks may involve less material removal.

Electrical

Unchanged

Colours

dark oxide
light etched metal
substrate contrast

Appearance

Dark or light stencil-defined mark with shallow recess and minimal mechanical deformation.

Specifications for Electrochemical etch

The documents a drawing cites to define this finish, with the Type / Class rows that apply. Each links to a page explaining the standard, and US Government documents are free to download there.

Test and related methods: MIL-STD-130 (Identification Marking of U.S. Military Property).

Drawing call-out

ELECTROCHEMICALLY ETCH PART NO. AND LOT CODE PER MIL-STD-130, 2.5 MM CHARACTER HEIGHT, 0.010–0.025 MM DEEP, BLACK

Which materials take Electrochemical etch?

Verdict per material family, with the grades that behave differently. Each family links to its datasheets in the material library.

Material family	Verdict	Notes
Brass	Yes	Conductive brass etches readily with a matched electrolyte.
Stainless Steel	Yes	Common, with alloy-specific electrolyte and complete neutralization.
Steel	Yes	Common on hardened tools and components.
Aluminum	With care	Possible with compatible chemistry; oxide and coatings can interrupt current.
Copper Alloy	With care	Possible with alloy-specific electrolyte and stain control.
Magnesium Alloy	With care	Possible with a magnesium-safe electrolyte; complete neutralization is required.
Titanium	With care	Possible with a titanium-qualified electrolyte and waveform.
Zinc Alloy	With care	Possible with a zinc-compatible electrolyte; poor rinsing stains quickly.
Ceramic	No	Typical ceramics are insulating and cannot be electrochemically etched.
Glass	No	Glass is insulating and cannot be electrochemically etched.
Polymer	No	Electrochemical etching requires an electrically conductive substrate.

How Electrochemical etch is applied, and what it does to the part

1Clean surface
2Position stencil
3Wet with alloy-specific electrolyte
4Apply electrode and current
5Remove stencil
6Neutralize and rinse
7Dry and inspect

Dimensions	Localized removal is typically 2–25 µm and has negligible effect on bulk dimensions.
Masking	Usually needed. The stencil masks the image; protect adjacent seams, contacts, crevices, and corrosion-critical surfaces from electrolyte.
Electrical	Unchanged
Appearance	Dark or light stencil-defined mark with shallow recess and minimal mechanical deformation.
Added lead time	1–3 working days on top of the bare part

Design rules for Electrochemical etch

What to decide on the drawing before the part goes to the finisher.

Use only on electrically conductive surfaces.Current must pass through the exposed artwork.
Provide a smooth area large enough for the stencil and electrode pad.Uniform pressure and wetting control image quality.
Keep marks away from crevices and sealed joints.Trapped electrolyte can cause staining or corrosion.
Specify dark oxide or material-removal etch.Waveform and resulting appearance differ.

Electrochemical etch versus the alternatives

Finishes engineers weigh against Electrochemical etch, and when each wins.

Finish	Hardness	Cosmetic	Cost	Thickness	Choose it when
Electrochemical etch this page	—	55	$$	2–25 µm	—
Laser Marking Electrochemical etch vs Laser Marking →	—	70	$	0–50 µm	for high-speed variable data
Chemical Etching Electrochemical etch vs Chemical Etching →	—	76	$$$	5–100 µm	for larger batch-imaged patterns

Electrochemical etchLaser Marking

The radar overlays Electrochemical etch with Laser Marking, its most common alternative — chosen for high-speed variable data. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Electrochemical Etching is a standard-cost finish ($$): cheaper than about 74 % of the finishes FabDigit quotes.

Finishing is priced per part with a lot minimum, from FabDigit's own China-side rates. The exact figure appears on the instant quote once the part is uploaded.

Lead time and compliance

Added lead time	1–3 working days
RoHS	Compliant
Notes	Finished-part compliance depends on complete neutralization and cleaning; spent electrolyte containing dissolved metal requires controlled disposal.

What Electrochemical etch is used for

Cutting tools
Surgical instruments
Stainless-steel components
Large assembled equipment
Lot and serial identification

Electrochemical etch — frequently asked

Electrochemical etching vs laser marking: which is better?

Electrochemical etching is portable and can mark hardened conductive metal about 2–25 µm deep with low equipment cost. Laser marking handles variable data faster and does not leave electrolyte to neutralize.

How deep is electrochemical etching?

Typical identification marks are shallow, about 2–25 µm in this catalog. Dark oxide recipes may remove less material than a light recessed etch.

Can electrochemical etching mark stainless steel?

Yes, and stainless tools and instruments are common applications. Use the correct electrolyte and neutralizer, then rinse and dry completely to protect corrosion performance.

Can electrochemical etching mark plastic or glass?

No, not directly, because the workpiece must conduct current. The broad v1 compatibility list is not technically applicable to insulating polymer, glass, ceramic, or composite substrates.

Are electrochemically etched marks permanent?

The 2–25 µm recessed or oxide mark is permanent under normal handling, but aggressive polishing can remove it. Define required service abrasion and confirm with a representative test.