Mechanical Engraving: Thickness, Specs & Materials

What is Mechanical engraving?

It provides a permanent recessed mark that remains identifiable after ink is lost.

How it works

A CNC spindle, pantograph, or drag tool follows vector artwork while the part is rigidly fixtured. A V-cutter varies line width with depth; a small end mill creates constant-width grooves; a diamond drag tool scribes a fine line. The groove may be left natural or paint-filled for contrast. Cutter geometry, runout, depth control, burr formation, and surface curvature govern legibility.

Why specify it

Creates a permanent recessed mark
Supports variable serial numbers under CNC control
Typical shallow depth is 50–500 µm
Can be paint-filled for high contrast

Where it falls short

Requires tool access and rigid fixturing
Creates chips and may raise burrs
Slower than laser marking for dense variable codes
Deep cuts can weaken thin or highly stressed sections

Mechanical engraving at a glance

Mechanical engraving is a middle-of-the-range finish; its best score is cosmetic quality (58 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 qualityGood58 / 100

LubricityMinimal10 / 100

Relative costStandard32 / 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.

Mechanical engraving key numbers

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

Thickness50–500 µm2–20 mil

Thickness

50–500 µm recessed cut depth for part marking; deeper decorative engraving requires separate review.

Electrical

Unchanged

Colours

substrate colour
optional paint fill

Appearance

Crisp recessed grooves with machined or scribed texture; optional contrasting fill.

Specifications for Mechanical engraving

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

MECHANICALLY ENGRAVE PART NO. AND SERIAL NO. PER MIL-STD-130, 2.5 MM CHARACTER HEIGHT, 0.20 MM DEPTH, WHITE PAINT FILL

Which materials take Mechanical engraving?

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

Material family	Verdict	Notes
Aluminum	Yes	Machines readily; protect or restore corrosion finish if cut after coating.
Brass	Yes	A standard engraving substrate.
Copper Alloy	Yes	Soft copper engraves easily; burrs raise quickly.
Polymer	Yes	Rigid polymers engrave well; heat and burr response vary.
Stainless Steel	Yes	Use suitable cutters and remove burrs.
Steel	Yes	Tooling and feed depend on hardness.
Titanium	Yes	Engraves with rigid fixturing and sharp carbide tools.
Magnesium Alloy	With care	Possible with sharp tools and fire-safe chip control.
Zinc Alloy	With care	Soft zinc engraves easily and raises burrs.
Ceramic	Limited	Possible with diamond tooling on selected ceramics; chipping is common.
Glass	Limited	Possible with diamond tooling; fracture risk is high.

How Mechanical engraving is applied, and what it does to the part

1Fixture to datum
2Load vector artwork
3Set cutter and zero
4Engrave
5Deburr and clean
6Apply fill if specified
7Inspect depth and content

Dimensions	The mark removes 50–500 µm locally; maintain remaining wall thickness and edge distance.
Masking	Rarely needed. Protect adjacent cosmetic finishes from chips and fixture contact.
Electrical	Unchanged
Appearance	Crisp recessed grooves with machined or scribed texture; optional contrasting fill.
Added lead time	2–5 working days on top of the bare part

Design rules for Mechanical engraving

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

Provide a flat, rigidly supported marking area.Depth accuracy depends on stable tool-to-part distance.
Keep groove depth below the remaining-wall and stress limits.Engraving is a material-removal notch.
Use open fonts and adequate spacing.Small cutters and paint fill can close narrow counters.
Locate artwork away from sealing and bearing surfaces.Burrs and grooves alter contact.

Mechanical engraving versus the alternatives

Finishes engineers weigh against Mechanical engraving, and when each wins.

Finish	Hardness	Cosmetic	Cost	Thickness	Choose it when
Mechanical engraving this page	—	58	$$	50–500 µm	—
Laser Marking Mechanical engraving vs Laser Marking →	—	70	$	0–50 µm	for finer noncontact variable data
Dot Peen Marking Mechanical engraving vs Dot Peen Marking →	—	35	$	50–500 µm	for faster indented serial marking

Mechanical engravingLaser Marking

The radar overlays Mechanical engraving with Laser Marking, its most common alternative — chosen for finer noncontact variable data. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Mechanical Engraving is a standard-cost finish ($$): cheaper than about 64 % 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	2–5 working days
RoHS	Compliant
Notes	The cut itself adds no restricted substance; paint fill, coolant, and cleaning chemistry require separate control.

What Mechanical engraving is used for

Nameplates
Valve and instrument scales
Part numbers
Serial numbers
Decorative monograms

Mechanical engraving — frequently asked

Laser marking vs mechanical engraving: which lasts longer?

A 50–500 µm mechanical groove remains visible after surface colour is removed and is easy to feel. Laser marks can be equally permanent but may use zero-depth annealing or only up to 50 µm shallow engraving, so specify the required mechanism.

How deep should part-number engraving be?

A typical shallow job-shop range is 50–500 µm. Select depth from required permanence, character size, wall thickness, stress, and whether paint fill is needed.

Can mechanical engraving be used on curved parts?

It can follow gentle curvature with multi-axis motion or compliant diamond drag tools. Abrupt curvature requires special fixturing and may change line width or depth.

Does engraving damage anodizing?

Yes, cutting after anodizing removes the oxide in the groove and exposes aluminum. Engrave before anodizing for a coated groove, or approve a post-engrave seal or paint fill.

Can engraved marks meet MIL-STD-130?

Mechanical engraving can be used when the specified identification content, location, size, and permanence satisfy the drawing and applicable MIL-STD-130 requirements. The drawing still needs a complete marking callout.