---
type: process
name: "CNC Engraving"
category: "Finishing"
subcategory: "Subtractive"
materials: ["Metal", "Plastic", "Wood", "Glass"]
tolerances: "Depth control of ±0.001–0.002 in (±0.025–0.05 mm) is routine; stroke width with a conical tool varies directly with depth, so both must be specified together"
volumes: "1 to tens of thousands of parts; cost per part is dominated by cycle time above a few hundred"
lead_time: "1–5 business days; no tooling lead time beyond stock cutters"
url: https://manufacturingprocesses.org/processes/finishing/cnc-engraving
---

# CNC Engraving

CNC engraving cuts text and artwork into a surface with a small pointed or ball-nose tool following a programmed path.

- **Category**: [Finishing](https://manufacturingprocesses.org/processes/finishing.md)
- **Family**: Subtractive
- **Materials**: Metal, Plastic, Wood, Glass
- **Typical tolerances**: Depth control of ±0.001–0.002 in (±0.025–0.05 mm) is routine; stroke width with a conical tool varies directly with depth, so both must be specified together
- **Surface finish**: Groove walls come out as-machined; ductile metals raise a fine burr that must be removed before any paint fill
- **Typical volumes**: 1 to tens of thousands of parts; cost per part is dominated by cycle time above a few hundred
- **Lead time**: 1–5 business days; no tooling lead time beyond stock cutters

## Overview

CNC engraving cuts text, artwork and serial data into a surface with a small rotating tool following a programmed path. Unlike laser marking, it is a mechanical cutting process, so it produces genuine depth with a defined cross-section in any machinable material, and the resulting groove can be filled with paint or lacquer for contrast.

Typical engraved depth for text is 0.005–0.020 in (0.13–0.5 mm), cut with a conical engraving tool whose flat tip runs from about 0.005 in to 0.030 in (0.13–0.75 mm), or with a small ball-nose end mill. Because the conical tool gets wider as it goes deeper, stroke width is a function of depth — a designer controls line weight by controlling Z. Spindle speeds are high, commonly 10,000–24,000 rpm on small cutters. Diamond drag engraving, in which a non-rotating stylus scratches the surface at 0.001–0.003 in (25–75 µm), is the low-force alternative for thin, hardened or delicate parts.

## How it works

1. **Prepare the artwork.** Engraving uses single-line (stick) fonts wherever possible, so each character is one toolpath rather than an outlined shape that must be pocketed. Outline fonts and logos require the enclosed area to be cleared out, which multiplies cycle time.

2. **Choose the tool.** A conical engraving tool with a defined tip flat and an included angle of roughly 15–90° is the standard choice: the shallow angle gives a strong tip and a stroke width that grows predictably with depth. Ball-nose end mills give a constant-width, round-bottom groove. Diamond drag styli scratch rather than cut and need almost no spindle power or rigidity.

3. **Cut.** The tool follows the toolpath at high spindle speed and modest feed. Depth is usually taken in one pass for text under about 0.010 in (0.25 mm) and in multiple passes below that. Chip evacuation and heat matter: acrylic and many thermoplastics melt and re-weld unless a single-flute O-flute cutter and high feed are used.

4. **Deburr.** Engraving raises a fine burr at the groove edges on ductile metals. A light hand deburr, bead blast or vibratory pass removes it — and must be done before any paint fill.

5. **Fill (optional).** A lacquer stick or paint is wiped into the groove and the excess removed from the surface. Fill depth and groove width determine how well the fill holds; shallow, narrow grooves shed fill in service.

### Where it beats laser marking

Engraving produces real depth in any material regardless of optical absorption, so it works on bare aluminum, copper, brass and clear plastics where a fiber laser struggles. It gives a groove that holds paint fill, and it produces a tactile result for control panels and safety markings. It is also the practical route to cutting through a two-color engraving laminate, where the top layer is removed to expose a contrasting core.

## Design guidelines

### Set line weight through depth, not through the drawing

With a conical tool, stroke width grows as the tool goes deeper. A 0.010 in wide stroke and a 0.020 in wide stroke on the same part require two different depths or two different tools. Specify the depth and the tool tip, or specify the stroke width and let the shop compute depth — but do not assume a drawn line weight will be reproduced.

### Respect the minimum internal radius

Every internal corner in the artwork is limited by the tool's effective radius at cutting depth. Sharp corners in a logo come out radiused. Keep detail features above roughly 0.010 in (0.25 mm) and expect finer detail to soften.

### Size characters for legibility and for fill

Practical minimum character height is around 0.060 in (1.5 mm) for a clean engraved result, and around 0.100 in (2.5 mm) if the groove must hold paint fill reliably. Below that, the fill will not stay in and the characters lose definition.

### Keep engraving off thin and unsupported walls

Cutting force deflects thin sections, and a deflecting wall produces an inconsistent depth and therefore an inconsistent stroke width. Support the area under the engraving, or use diamond drag engraving, which applies almost no force.

### Sequence it with the surface finish

Engraving before anodizing gives a groove that anodizes along with the rest of the part — subtle, uniform, corrosion-protected. Engraving after anodizing cuts through the colored layer and exposes bright metal, giving high contrast but leaving bare aluminum in the groove. Choose deliberately, and note that engraving after bead blasting will leave a bright groove against a matte field.

### Match the tool and speed to the material

Aluminum and brass engrave cleanly at high speed. Stainless and tool steels need slower feeds and a stronger tip angle. Acrylic and polycarbonate melt unless chip evacuation is aggressive. Wood and engraving laminates cut easily but chip at the edges of the stroke.

| Feature | Recommended | Limit | Why |
| --- | --- | --- | --- |
| Engraved depth (text) | 0.005–0.020 in (0.13–0.5 mm) | — | Deeper needs multiple passes and widens the stroke |
| Diamond drag depth | 0.001–0.003 in (25–75 µm) | Scratch only, no fill | Non-rotating stylus, minimal force |
| Minimum character height | 0.060 in (1.5 mm) | 0.100 in (2.5 mm) if paint filled | Fill will not stay in a small groove |
| Minimum internal detail | 0.010 in (0.25 mm) | Set by tool radius at depth | Corners radius to the tool |
| Spindle speed | 10,000–24,000 rpm | — | Small-diameter tools need high surface speed |
| Sequence with anodize | Before for uniform color, after for contrast | — | Engraving after anodize exposes bare metal |

## Cost drivers

CNC engraving is priced as machining time plus setup, so it behaves like any other milling operation: cheap per part at volume, dominated by setup at low volume.

- **Engraved area and path length.** Cycle time follows total toolpath. Outlined or filled artwork that must be pocketed can take ten times as long as the same design in a single-line font.
- **Setup and fixturing.** Locating the part repeatably under the spindle is the fixed cost. Flat plates are trivial; contoured or cylindrical parts need dedicated work holding or an additional axis.
- **Tooling.** Engraving tips are small and wear quickly in hard materials; tip replacement frequency on stainless is a real consumable cost.
- **Secondary operations.** Deburring and paint filling are hand operations, and paint fill in particular is priced per part.
- **Variable data.** Serial numbers require either a program per part or macro programming, and add handling time per piece.

Cost-reduction tactics:

1. Use single-line engraving fonts rather than outlined text — this is the single largest cycle-time lever.
2. Engrave in the same setup as the machining operation that produced the surface, avoiding a second fixture and load.
3. Keep engraved artwork simple and above the minimum detail size so it cuts in one pass with one tool.
4. Skip paint fill unless contrast is functionally required; an engraved groove on a blasted surface often reads well without it.
5. For variable data such as serial numbers on many parts, compare against laser marking — the laser has no tool wear and no per-part handling penalty.

## FAQ

### How deep should CNC engraving be?

Typical engraved text runs 0.005–0.020 in (0.13–0.5 mm) deep. Diamond drag engraving, which scratches with a non-rotating stylus, runs 0.001–0.003 in (25–75 µm). If the groove will be paint filled, stay toward the deeper end so the fill has something to hold onto.

### Why does my engraved line width change with depth?

Standard engraving tools are conical with a small tip flat, so the cutting width grows as the tool descends. Line weight is therefore a function of Z depth, not of the drawn artwork. Specify tip size and depth together, or specify the required stroke width and let the shop derive the depth.

### How small can engraved characters be?

Around 0.060 in (1.5 mm) character height for a clean result, and around 0.100 in (2.5 mm) if the groove has to hold paint fill. Internal detail is limited by the tool radius at depth, so features below roughly 0.010 in (0.25 mm) will soften and sharp corners will come out radiused.

### CNC engraving or laser marking?

Engraving for genuine depth, for a groove that holds paint fill, for a tactile result, and for materials that laser sources handle poorly such as bare aluminum, copper and clear plastics. Laser marking for speed, for variable data at no extra cost, for no tool wear, and for marks on surfaces that must not be cut into.

### Should I engrave before or after anodizing?

Before, if you want the groove anodized along with the rest of the part for a uniform, corrosion-protected result. After, if you want maximum contrast — cutting through the colored anodic layer exposes bright metal, but leaves that groove unprotected.

### What font should I use for CNC engraving?

A single-line or stick font, where each character is one toolpath. Outlined fonts require the enclosed area to be cleared out, which can multiply cycle time by an order of magnitude for no visual benefit at small sizes.

## Alternative processes

- [Laser Marking and Engraving](https://manufacturingprocesses.org/processes/finishing/laser-marking-and-engraving.md): Laser marking alters the surface with a focused beam — annealing, etching or engraving it — to make permanent, contact-free marks.
- [Photo Etching](https://manufacturingprocesses.org/processes/finishing/photo-etching.md): Photo etching masks a surface photographically and etches shallow detail into it for decoration, marking or texture.
- [Pad Printing](https://manufacturingprocesses.org/processes/finishing/pad-printing.md): Pad printing lifts ink out of an etched plate with a silicone pad and transfers it onto a curved or recessed surface.
- [Screen Printing](https://manufacturingprocesses.org/processes/finishing/screen-printing.md): Screen printing pushes ink through a stencilled mesh onto the surface below, laying down one opaque color per pass.
- [Foil Blocking and Embossing](https://manufacturingprocesses.org/processes/finishing/foil-blocking-and-embossing.md): Foil blocking and embossing press a heated die into the surface to transfer metallic foil, raise a relief, or do both at once.

## Related processes

- [Laser Marking and Engraving](https://manufacturingprocesses.org/processes/finishing/laser-marking-and-engraving.md): Laser marking alters the surface with a focused beam — annealing, etching or engraving it — to make permanent, contact-free marks.
- [CNC Milling](https://manufacturingprocesses.org/processes/cutting/cnc-milling.md): CNC milling removes material with a rotating multi-flute cutter moved along programmed paths, producing prismatic parts from solid stock.
- [Photo Etching](https://manufacturingprocesses.org/processes/finishing/photo-etching.md): Photo etching masks a surface photographically and etches shallow detail into it for decoration, marking or texture.
- [Anodizing](https://manufacturingprocesses.org/processes/finishing/anodizing.md): Anodizing grows a hard porous oxide layer on aluminum electrochemically, which can then be dyed and sealed for wear and corrosion resistance.
- [Screen Printing](https://manufacturingprocesses.org/processes/finishing/screen-printing.md): Screen printing pushes ink through a stencilled mesh onto the surface below, laying down one opaque color per pass.

---

*Source: [Manufacturing Processes](https://manufacturingprocesses.org/processes/finishing/cnc-engraving)*

*Last updated: August 11, 2026*