Dot Peen Marking: Thickness, Specs (MIL-STD-130) & Materials

What is Dot peen?

It is used for serial numbers, VIN-like identifiers, UDI, and traceability on industrial metal parts.

How it works

A carbide or diamond stylus is driven pneumatically or electromagnetically while an XY mechanism positions each impact. Dot spacing and force form alphanumeric strokes or Data Matrix cells. The part must be supported so impact energy creates an indentation rather than vibration or bending. Controller software can insert variable data from a production system. Depth, dot diameter, pitch, and surface finish determine legibility and code grade.

Why specify it

Automates variable serial and lot data
Creates 50–500 µm permanent indentations
Marks rough or scaled metal more robustly than many optical colour-change methods
Can create Data Matrix direct-part marks

Where it falls short

Impact noise and vibration require rigid fixturing
Can deform thin sections or damage brittle materials
Dot pattern is less cosmetic than laser or print
Machine-readable codes require grading after marking

Dot peen at a glance

Dot peen is a middle-of-the-range finish; its best score is cosmetic quality (35 of 100), at a budget 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 qualityFair35 / 100

LubricityMinimal10 / 100

Relative costBudget18 / 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.

Dot peen 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 indentation depth; low-stress marking uses the shallow end of the range.

Electrical

Unchanged

Colours

substrate colour
shadow contrast

Appearance

Industrial dotted characters or cells with visible and tactile indentations.

Specifications for Dot peen

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.

Standard	Type / Class	Thickness	Requirement / test	Status
MIL-STD-130 Identification Marking of U.S. Military Property · DoD	Human-readable information	—	Free-text identification containing the required enterprise identifier and part or identifying number, plus other contract data. · Visual legibility, content, location, permanence, and workmanship.	Active
	Machine-readable information	—	Linear or two-dimensional machine-readable marking, including IUID data when required. · Data syntax, symbol verification, readability, permanence, and contract-specified quality grade.
	Item Unique Identification	—	Machine-readable unique item identifier constructed from approved enterprise and item data elements. · UII construct validation, data-content verification, symbol quality, and permanence.

Test and related methods: ISO 15415 (Automatic Identification and Data Capture Techniques — Bar Code Symbol Print Quality Test Specification — Two-Dimensional Symbols), AS9132 (Data Matrix Quality Requirements for Parts Marking).

Drawing call-out

DOT PEEN MARK PER MIL-STD-130, DATA MATRIX ECC200, 8 × 8 MM, 0.25 MM DOT PITCH, 0.10–0.20 MM DEEP, GRADE 2.5 MIN PER ISO 15415

Pattern: MARK PER MIL-STD-130, METHOD <LASER|DOT PEEN|ELECTROCHEMICAL ETCH|LABEL>, CONTENT <DATA ELEMENTS>, LOCATION AS SHOWN, [IUID/MRI REQUIREMENTS]

Which materials take Dot peen?

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	Marks readily; reduce force on thin walls.
Brass	Yes	Takes a clear indent at low force.
Stainless Steel	Yes	Common with carbide stylus and rigid support.
Steel	Yes	A primary application, subject to hardness capability.
Copper Alloy	With care	Soft copper takes a deep indent and can raise a rim; support the part.
Magnesium Alloy	With care	Possible at low force; thin magnesium walls distort and raise a fire-risk chip.
Titanium	With care	Mark depth and fatigue location require review.
Zinc Alloy	With care	Soft zinc takes a deep indent and can raise a rim; support the part.
Polymer	Limited	Rigid plastics can take a shallow mark; most polymers rebound or crack.
Ceramic	No	Impact marking fractures ceramics.
Glass	No	Impact marking fractures glass.

How Dot peen is applied, and what it does to the part

1Fixture and support part
2Load layout and variable data
3Set stylus force and dot pitch
4Mark
5Clean if required
6Verify content and code grade

Dimensions	Each dot displaces material 50–500 µm deep and can print through unsupported thin walls.
Masking	Rarely needed. Protect adjacent cosmetic surfaces and coatings from fixture and stylus contact.
Electrical	Unchanged
Appearance	Industrial dotted characters or cells with visible and tactile indentations.
Added lead time	1–2 working days on top of the bare part

Design rules for Dot peen

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

Provide rigid support directly behind the marking area.Impact on unsupported walls causes bounce and distortion.
Keep the mark away from fatigue-critical edges and thin membranes.Indentations are local stress raisers.
Specify dot depth, pitch, code size, and verification grade.Readability cannot be controlled by character height alone.
Use a locally flat area for machine-readable codes.Curvature changes lighting and dot geometry.

Dot peen versus the alternatives

Finishes engineers weigh against Dot peen, and when each wins.

Finish	Hardness	Cosmetic	Cost	Thickness	Choose it when
Dot peen this page	—	35	$	50–500 µm	—
Laser Marking Dot peen vs Laser Marking →	—	70	$	0–50 µm	for finer, quieter, noncontact marking
Steel Stamp Part Marking Dot peen vs Steel Stamp Part Marking →	—	38	$	100–500 µm	for simple repeated fixed characters

Dot peenLaser Marking

The radar overlays Dot peen with Laser Marking, its most common alternative — chosen for finer, quieter, noncontact marking. Scores in the table are 0–100 across every finish in the catalog.

Cost, lead time and compliance

Relative cost

Dot Peen Marking is a budget-cost finish ($): cheaper than about 81 % 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	1–2 working days
RoHS	Compliant
Notes	The process adds no ink or chemical coating; extraction may be needed if marking breaks an existing hazardous coating.

What Dot peen is used for

Automotive traceability
Aerospace part identification
Heavy-equipment serial numbers
UDI on robust instruments
Data Matrix direct-part marks

Dot peen — frequently asked

Dot peen vs laser marking: which is more permanent?

Dot peen leaves 50–500 µm indentations that remain after surface colour and paint wear. Laser marking can be zero-depth or engraved up to about 50 µm in this catalog, but offers finer and more cosmetic results.

Can dot peen mark a Data Matrix code?

Yes, dot peen can form ECC200 direct-part marks. Grade the finished symbol to ISO 15415 and control dot pitch, depth, quiet zone, lighting, and surface curvature.

How deep is dot peen marking?

A typical working range is 50–500 µm, with shallow settings used where stress or wall thickness matters. Put a minimum and maximum depth on the drawing when permanence is critical.

Can dot peen mark thin sheet metal?

It can, but the sheet needs close backing and reduced impact energy. Inspect the reverse face because dots can print through or warp an unsupported panel.

Does dot peen marking affect fatigue life?

Each indentation acts as a small notch, so location and depth matter on cyclically loaded parts. Keep marks out of high-stress zones and obtain engineering approval for fatigue-critical hardware.