Text Milling: Fonts, Depth, Materials, and Costs for CNC Engraving

A designer might perfectly configure the logo engraving in CAD—with the typeface and spacing looking flawless—only to be told by the factory that the batch requires rework. The issue usually isn’t the aesthetics of the font itself, but rather strokes that are too fine or depth settings that lack precision, making it impossible for the cutting tool to reliably reproduce the design. While text milling may seem like a simple “engraving” task, a mismatch in any variable—typeface, line width, depth, or material—can lead to problems ranging from blurred text and burred edges to the need for rework or even the rejection of the entire batch of cosmetic parts. This article briefly explains the machining principles but focuses primarily on the critical choices that must be made during the design phase.

Ⅰ. What is Text Milling?

In CNC machining, “text milling” refers to a process in which a CNC milling machine uses a cutting tool to machine the surface of a workpiece—following a preset font outline or path—to create clear text, numbers, or symbols. This method is commonly used for surface marking on materials such as metal and plastic, producing elements like part numbers, product models, nameplate details, and brand logos. Depending on the specific machining approach, text milling can employ techniques such as contour milling, single-line font machining, or pocket milling to meet varying requirements for precision, depth, and visual appearance; it is one of the standard methods for marking in CNC machining.

The workflow from CAD to G-code for text milling consists of four steps: designing the text outline in CAD → exporting it as a vector file (DXF/SVG) → generating the toolpath using CAM software → outputting the G-code and machining. During the CAD phase, designers must ensure that fonts are converted into vector lines rather than bitmaps; otherwise, the CAM software will be unable to generate a machinable toolpath. DXF or SVG formats are recommended to preserve vector precision.

Text milling is a reliable CNC machining method to etch characters, serial codes and logos onto metal parts. Commonly adopted in automation, automotive and machinery manufacturing for component identification.

Ⅱ. When Should You Choose Text Milling?

Text milling is better suited for applications that demand high levels of durability, reliability, and long-term readability for markings. Unlike surface printing or shallow marking, CNC milling creates permanent recesses by removing material, making the markings resistant to degradation from friction, cleaning, or environmental exposure. Consider the following criteria when making your choice:

Requirement for long-term wear and corrosion resistance → Prioritize Text Milling

For applications such as outdoor equipment, chemical processing equipment nameplates, and machinery part markings, shallow laser markings or ink-based labels may fade over time when exposed to rain, oil, or cleaning agents; milled text, however, remains legible for the long term.

Requirement for permanent traceability → Prioritize Text Milling

For items such as aerospace components, mold identification numbers, and industrial equipment serial numbers, clear identification must be maintained throughout the product’s lifecycle to prevent tracking difficulties caused by damaged markings.

Requirement for a premium appearance and mechanical aesthetic → Choose Text Milling

For precision equipment, aluminum housings, and high-end product components, the three-dimensional recesses created by milling offer a distinct machined-metal look; this can be further enhanced through processes such as sandblasting or anodizing.

For metal parts requiring significant depth and defined edges → Choose Text Milling

For metal components made of materials such as aluminum alloy, brass, or stainless steel, CNC milling/engraving achieves superior depth and edge definition, making it ideal for applications requiring crisp lettering and precise dimensions.

When Text Milling is not recommended

If production volumes are extremely high, markings change frequently, or only low-cost surface labeling is required, methods such as screen printing, labeling, or laser engraving are usually more economical. For instance, in scenarios like disposable packaging or mass-produced consumer electronics housings, CNC milling/engraving could incur unnecessary processing costs.

Ⅲ. Text Milling vs. Laser Engraving vs. Screen Printing vs. Labeling

CNC milling is not the only method for text marking; different processing techniques vary significantly in terms of cost, durability, machining depth, and suitability for specific applications. Depending on the product’s intended use, operating environment, and lifespan requirements, one can choose from options such as text milling, laser engraving, screen printing, or labeling. Below is a comparison of several common marking methods.

In terms of long-term use and reliability, physical processing methods generally offer superior wear resistance, whereas surface treatment methods are better suited for cost-sensitive, high-volume production scenarios. The final choice should take into account factors such as the material, operating environment, required lifespan of the markings, and production volume.

Ⅳ. Choosing the Right Text Milling Method

Selecting the machining method is a critical decision in Text Milling design, as different approaches significantly impact tooling, depth, font appearance, and cost. The following five methods cover the vast majority of application scenarios.

Single-Line Engraving

This method involves tracing the font’s centerline using a V-bit or a small-diameter end mill, completing the cut in a single pass. Advantages: fastest machining speed, simple programming, and suitability for small text. Disadvantages: stroke width is determined by the tool, preventing variation in line thickness. Suitable for: serial numbers, batch numbers, rapid marking, and small text (2–4 mm character height).

Achieve crisp, delicate lettering on metal parts using professional CNC text milling single-line engraving technology. Widely adopted in mold manufacturing, hardware accessories and mechanical component identification for permanent, readable markings.

Profile Milling

The tool follows the outer contour of the characters, resulting in crisp edges. Pros: High fidelity to character shape, clean edges, and maximum versatility. Cons: Slower than single-line milling; requires matching tool diameter to stroke width. Suitable for: Medium-sized characters (4–15mm), applications requiring sharp edges, and general industrial signage.

CNC profile milling delivers consistent contoured shapes on aluminum and steel workpieces. Widely adopted in precision machinery, automotive and automation parts production for tight tolerance finished profiles.

Pocket Milling

The interior of the character is hollowed out to create a deep, recessed effect. Pros: Significant depth, high contrast, and allows for color filling (e.g., black paint). Cons: Longest machining time and significant tool wear. Suitable for: Color-filled logos, high-contrast decorative elements, and deep lettering (>0.5mm depth).

CNC pocket milling is widely used in mechanical manufacturing to machine enclosed cavities in aluminum, steel and alloy materials. This process delivers consistent depth control and smooth inner surfaces for mold parts and automation components.

V-Carving

Uses a V-shaped tool, with stroke width varying according to carving depth. Pros: Strong decorative appeal, three-dimensional look, and a single tool can handle various line widths. Cons: Requires a specialized V-bit and high precision in depth control. Suitable for: Decorative fonts, calligraphic styles, and wood or plastic ornaments.

V-Carving is a popular text milling technique using V-shaped cutters to create crisp tapered lettering. Widely used for nameplates, mechanical labels, signage and custom machined component marking across manufacturing industries.

Raised/Embossed Text

Material surrounding the characters is milled away, leaving the characters themselves raised. Pros: Superior durability, striking visual impact, and withstands frequent cleaning. Cons: Longest machining time and highest cost. Suitable for: Logo components, high-end products, and surfaces subject to frequent touching or cleaning.

High-precision CNC routing creates crisp raised embossed text on metal components. This marking method delivers durable, legible branding and part identification widely used within custom mechanical manufacturing and precision engineering assemblies.

Processing Method Selection Table

Ⅴ. Design Standards Quick Reference Chart

The hardness, toughness, and machinability of different materials directly affect the minimum machinable dimensions for CNC engraving. While soft materials are generally easy to process, issues such as burrs and deformation require attention; conversely, hard metals offer durability but place greater demands on cutting tools and machining parameters. Therefore, when designing text, factors such as character height, line width, character spacing, and engraving depth should be adjusted according to the material type. The following parameters serve as design references for various materials.

The parameters above represent typical ranges for CNC lettering designs; actual machining results are also influenced by factors such as tool diameter, character structure, machining method, and equipment rigidity. For small-scale text or complex typefaces, it is recommended to conduct sample tests prior to full-scale production to verify text clarity and machining stability.

Ⅵ. How Should You Choose a Font?

The results of CNC engraving depend not only on the choice of font and cutting tool but also closely on material properties. Differences in hardness, toughness, machinability, and thermal stability among materials directly affect machining difficulty, the clarity of the lettering, and surface quality. This overview covers common machining materials, those best suited for engraving, and key considerations for materials that are difficult to machine, helping you select the most appropriate processing strategy during the design phase.

Commonly used fonts

Recommended Fonts

Ⅶ. What Are the Applications of Text Milling?

Model and Serial Number Identification:For Production Management and Quality Traceability

Product model numbers and serial numbers are the most common forms of permanent identification for industrial parts. Model numbers distinguish between different specifications, versions, or configurations, facilitating production, assembly, and inventory management while preventing the mix-up of parts. Serial numbers establish a unique identity for each product, supporting production records, inspection data, after-sales maintenance, and quality traceability. The absence of this information can easily lead to batch confusion and maintenance difficulties, and may even make it impossible to rapidly pinpoint quality issues.

Logos and Brand Names: For Product Identification and Branding

Logos and brand names serve primarily to enhance product recognition and brand image; they are commonly found on equipment housings, consumer products, industrial components, and high-end mechanical parts. Compared to labeling or printing, CNC milling and engraving offer superior durability, ensuring the markings remain clear over the long term. For high-value products, permanent branding not only prevents confusion but also elevates the product’s perceived quality and professional appearance.

Medical UDI and Aerospace Traceability Markings: Meeting Regulatory and Compliance Requirements

Markings on medical devices and aerospace components are not merely for displaying information; they are an essential element of quality management systems. Medical devices typically require UDI, batch, and manufacturing details to satisfy regulatory requirements and support full lifecycle traceability, while aerospace parts require the recording of information such as part numbers, manufacturer details, and batch data to ensure the traceability of every critical component. Failure to achieve clear, durable markings can lead to compliance risks and quality management issues.

Mold Identification and Production Management Markings: Enhancing Manufacturing Efficiency

Mold identification numbers serve primarily to distinguish between different molds, cavities, and production versions, facilitating daily management, maintenance, and the tracking of service life. In mass production, clear, permanent markings enable the rapid assessment of a mold’s status, thereby reducing production errors and improving maintenance efficiency. A lack of effective identification can easily lead to the mixing up of molds, the loss of maintenance records, and difficulties in quality analysis.

Ⅷ. How Should Cutting Tools be Selected?

In CNC engraving, the choice of tool type and size must align with the specific structure of the typeface. Different fonts vary in terms of stroke width, level of detail, and machining paths; using a tool that is too small can reduce efficiency, while one that is too large may fail to accurately reproduce the font’s details. Therefore, once a font is selected, the appropriate tool specifications should be determined by considering the text size, machining depth, and material properties. The following serves as a reference for matching common font types with recommended tools.

Ⅸ. Precautions for Processing Different Materials

The results of CNC engraving depend not only on the choice of font and cutting tool but also closely on material properties. Differences in hardness, toughness, machinability, and thermal stability among materials directly affect machining difficulty, the clarity of the lettering, and surface quality. This section outlines common machining materials, types suitable for engraving, and considerations for materials that are difficult to machine, helping you select the most appropriate processing strategy during the design phase.

What are the common materials?

Which materials are more suitable for processing?

Which materials are difficult to machine, and what precautions are required?

How can the formation of burrs be prevented?

When milling text, the key to avoiding burrs lies in the proper selection of cutting tools and the optimization of machining parameters. Sharp tools should be used to prevent the formation of burrs caused by dull tools crushing the material; additionally, spindle speed and feed rate must be appropriately matched to ensure stable cutting rather than a friction-based process. Climb milling is the preferred machining method to minimize tearing along the edges of the characters. Engraving depth is generally controlled between 0.2 mm and 0.6 mm, as excessive depth increases the risk of burrs. For plastic materials, temperature control is also necessary to prevent melting and stringing. If required, a slight chamfer or deburring step can be applied to achieve a cleaner finish on the lettering.

Ⅹ. How Does Text Milling Design Affect Machining Costs?

Factors Affecting Machining Difficulty

• Font Complexity

Font style is a primary factor influencing cost. Simple sans-serif fonts (such as ISO 3098 or DIN 1451) feature straightforward, continuous toolpaths and offer high machining efficiency. In contrast, complex fonts (such as script or decorative typefaces) involve numerous curves, intricate details, and frequent directional changes; these significantly increase toolpath calculation complexity and machining time, while also raising the risk of tool breakage and necessitating slower feed rates, thereby driving up costs.

• Engraving Depth

Greater engraving depth results in increased machining time and higher tool loads. Shallow engraving (0.2–0.3 mm) typically requires only a single pass, whereas deep engraving (over 0.6 mm) often necessitates multi-layer machining and places greater demands on chip evacuation and cooling. These factors not only extend the production cycle but also accelerate tool wear, leading to a significant rise in costs.

• Font Size

Smaller font sizes increase machining difficulty. Small text requires smaller-diameter tools (e.g., 0.2–0.5 mm); these tools lack rigidity, are prone to breakage, and require slower feed rates, all of which reduce overall machining efficiency. Conversely, larger fonts allow for the use of larger tools that cover a greater surface area per cut, resulting in lower unit costs.

• Materials

Material choice significantly impacts costs. Aluminum alloys and brass offer excellent machinability—allowing for high processing speeds and extended tool life—resulting in lower costs. Conversely, high-strength materials like stainless steel and titanium alloys require slower feed rates, cause greater tool wear, and demand longer processing times, leading to a substantial increase in costs. While plastics are easy to machine, they are prone to burr formation, which can raise post-processing costs.

• Curves and Structural Complexity

Text designs featuring numerous curves and frequent directional changes result in complex machining paths; the need for the tool to frequently decelerate and change direction reduces feed efficiency. Additionally, small-radius curves may require smaller cutting tools, further driving up costs. Consequently, linear designs are more cost-effective than those with complex curves.

• Engraving Location

The placement of the text also affects costs. Machining efficiency is highest when text is located on a flat surface that is easy to clamp. In contrast, text located in deep cavities, on sidewalls, or in areas requiring multiple part reorientations increases setup time and fixture complexity. Furthermore, working in confined spaces may necessitate longer tools or specialized toolpath strategies, thereby increasing both machining risks and costs.

XI. How Can the Design be Optimized?

Optimizing the design for CNC text milling essentially involves making the text “easier to machine,” thereby reducing machining time, minimizing tool wear, and improving yield rates. First, regarding font selection, prioritize standard sans-serif or single-stroke fonts—such as ISO 3098, DIN 1451, or Simplex—and avoid complex, decorative typefaces to reduce toolpath complexity. Second, regarding dimensions, avoid excessively small text; ensure that line widths and spacing accommodate the minimum tool accessibility requirements. Otherwise, the use of micro-tools becomes necessary, which significantly lowers efficiency and increases costs. Engraving depth should ideally be kept within a shallow range of 0.2–0.5 mm to avoid the tool wear and multi-pass machining associated with deep engraving.

Regarding structural design, minimize intricate curves and overly complex shapes; prioritize straight lines and large-radius fillets to ensure a more stable and smooth toolpath. Additionally, position the text on flat areas that are easy to clamp, avoiding deep cavities, sidewalls, or locations near edges, so as to minimize clamping complexities and machining difficulties. Furthermore, consider tool accessibility during the design phase: ensure the minimum line width exceeds the tool diameter (with a safety margin) to prevent issues such as the inability to engage the tool or the need for rework. Through these optimizations, machining becomes more efficient, stable, and cost-effective without compromising legibility.

XII. Common Design Errors & Solutions

In actual machining, the design of text and patterns affects not only the visual quality of the part but also directly influences tool selection, machining efficiency, and the final outcome. Many machining issues stem not from the equipment or process itself, but from a failure to fully consider manufacturing feasibility during the design phase. The following summary outlines common design errors, their potential impact on machining, and corresponding optimization solutions, serving as a reference for CNC engraving and signage design.

XIII. Conclusion

CNC engraving cuts material using a cutting tool; it is suitable for applications requiring deep machining (such as with metals), offers a strong three-dimensional effect, but is slower and may produce burrs. Laser engraving uses a high-energy laser to ablate the surface; it is fast and ideal for fine marking, though it offers limited depth and may result in discoloration (blackening) or heat-affected zones. The former focuses on structural machining, while the latter focuses on rapid marking.