A CNC machine follows instructions from CAD software. The software tells the machine where and how to move its cutting tools. This approach replaces manual cutting methods and leads to more consistent results. The process works for both wood and metal. This article explores the key differences between CNC machining wood and CNC machining metal.
What is CNC Wood Machining?
Woodworkers have adopted CNC (computer numerical control) routers to speed up production and to improve precision . A CNC router follows a digital file to cut, carve, or shape wood pieces. The machine reads instructions from CAD/CAM software and moves along X, Y, and Z axes to create the desired form. Users can prepare designs in programs like Fusion 360 or VCarve Pro before sending them to the machine .
CNC machining wood can work with various wood types, such as oak for strength or pine for cost savings. They often secure the wood with clamps or vacuum hold‑downs to prevent movement during the cut . The result is cleaner edges, less waste, and faster turnaround.
Benefits of CNC Wood Machining
- The router hits exact dimensions every time.
- High feed rates speed up cutting, especially in softwoods.
- The same pattern repeats without variation.
- The machine handles complex shapes that are hard to carve by hand.
What is CNC Metal Machining?
Metalworkers often use CNC mills or machining centers to shape parts from steel, aluminum, or titanium . A CNC mill uses rotating tools like end mills, drills, and taps to remove material in precise steps. The process follows CAM-generated tool paths to ensure that each cut meets tight tolerances.
Operators choose CNC milling when they need strong parts with precise angles and smooth surfaces. The milling machine holds the metal workpiece firmly in a vise or fixture to avoid movement under cutting forces. Many shops add coolant systems to wash away chips and to lower heat at the cutting edge .
Benefits of CNC Metal Machining
- Machines can hold tolerances as tight as ±0.001 inch.
- Parts maintain full strength of the starting material.
- Each batch of parts matches the last.
- The machine can switch tools for drilling, tapping, or milling.
Key Differences Between CNC Machining Wood and Metal
The following sections highlight the main contrasts between wood and metal CNC machining.
Machine Types and Tooling
Both wood routers and metal mills share basic features like spindles and digital controls . However, they differ in structure, power, and common tool sets.
The table below summarizes these differences:
| Feature | CNC Wood Router | CNC Metal Mill |
|---|---|---|
| Frame | Lightweight, often aluminum or wood panels | Heavy steel or cast iron for rigidity |
| Spindle Power | 1–5 HP for cutting wood | 5–20+ HP to cut steel and alloys |
| Spindle Speed | 12,000–24,000 RPM | 3,000–10,000 RPM |
| Shank Diameter | ¼”, ½” for most bits | ¼”, ½”, ¾”, 1″ depending on required stiffness |
| Axis Rigidity | Lower stiffness, more vibration | Higher stiffness, minimal vibration |
| Software | User‑friendly CAD/CAM with graphical UI | Advanced CAM for complex tool paths |
| Dust/Coolant | Dust collection systems | Coolant systems and chip conveyors |
| Tool Shapes | Straight bits, V-bits, ball-nose bits | Flat end mills, ball-nose end mills, drills |
| Tool Coating | Rarely needed; plain carbide common | TiN, TiAlN, or diamond-like coatings for wear resistance |
| Feed Rates | 200–1,000 IPM (inches per minute) | 20–200 IPM |
| Cutting Forces | Lower | Higher |
| Workholding | Clamps, vacuum table | Vises, fixture plates |
Material Properties
Material choice has a direct impact on feed rates, tool life, and finish quality.
Wood Properties
- Grain Structure: Wood fibers can cause tear‑out if the feed rate is too high. Knots create stress points that need slower cutting speeds .
- Moisture Content: Wood expands or shrinks as moisture changes. Machines may need to adjust speed when moisture content exceeds 10% to avoid tool wear and poor finish .
- Hardness: Woods vary widely in hardness, measured by the Janka scale. The table below lists some common woods:
| Wood Type | Janka Hardness |
|---|---|
| Pine (Sugar) | 380 |
| Birch (Gray) | 760 |
| Maple (Sugar) | 1450 |
| Cherry | 950 |
| Walnut (Black) | 1010 |
| Oak (White) | 1360 |
Metal Properties
- Toughness: Metals demand slower feed rates to avoid work hardening and tool skip or chatter.
- Hardness and Strength: Steel and titanium resist cutting forces and require durable carbide or coated tools .
- Thermal Conductivity: Metals conduct heat away from the cut zone, but cutting can still create hot chips. Shops often use coolant to manage temperatures .
Below is a of typical metals used in CNC machining, with their hardness (approx. Brinell values) and thermal conductivity:
| Metal | Typical Hardness (HB) | Thermal Conductivity (W/m·K) |
|---|---|---|
| Aluminum (e.g. 6061‑T6) | 95–125 | 237 W/m·K |
| Mild Steel (AISI 1018) | 120–180 | 43 W/m·K |
| Stainless Steel (304) | 200–215 | 16 W/m·K |
| Titanium (Grade 5 Ti‑6Al‑4V) | 330 | 17 W/m·K |
Common Machining Techniques
Both wood and metal CNC machining use similar basic steps (clamping, tool path, cutting). They diverge in specific tool choices and speeds.
Wood Machining Techniques
- Milling: The router bit removes material to create flat surfaces or patterns .
- Drilling: The router forms precise holes for joinery or decoration .
- Routing: Designers use edge‑forming bits to shape profiles and flutes.
- Engraving: The router makes shallow cuts for letters or patterns.
- Carving: The router follows 3D tool paths to sculpt shapes, often with ball‑nose bits.
- Sanding: Some routers attach sanding heads to finish surfaces.
Metal Machining Techniques
- Facing: The mill flattens a surface to create a reference plane.
- Contour Milling: The cutter follows a 2D path to carve profiles.
- Slotting: The mill cuts slots for keys, splines, or gaps.
- Drilling and Tapping: The mill uses drills and taps to make and thread holes.
- 3D Milling: The mill moves along multiple axes to form complex shapes.
- Chamfering and Deburring: The mill cleans edges for assembly or safety.
Surface Finish and Tolerances
The expected quality of a machined surface and the required dimensional accuracy differ between wood and metal parts.
CNC Wood Machining Surface Finish
- Smooth finish
- Textured finish
- Sanded finish
- Natural wood grain exposure
- Engraved details
- Layered or stepped finishes
CNC Metal Machining Surface Finish
- Mirror finish
- Brushed finish
- Matte or satin finish
- High-tolerance flat finish
- Threaded or patterned finish
- Anodized-ready surface
Metal parts often need tighter tolerances, especially in aerospace or automotive. Wood parts typically allow more variation due to natural expansion and contraction.
| Material | Common Tolerance | Measurement Method |
|---|---|---|
| Wood | ±0.005″–0.020″ | Calipers, tape measure |
| Metal | ±0.0005″–0.005″ | Micrometer, CMM |
Cost Considerations
A wood router typically costs less than a metal mill. Entry‑level routers can start around $5,000. Entry‑level mills often start near $30,000. A high‑end router may reach $50,000. A high‑end mill can exceed $200,000. Tooling costs vary: wood bits cost $10–$50 each. Metal end mills cost $50–$200 each. Coolant systems for metal add another $2,000–$10,000.
Applications and Industries
Each process serves different market needs and products.
Wood CNC Applications
- Furniture: Tabletops, legs, and panels.
- Cabinetry: Doors, drawers, and face frames.
- Decorative Carvings: Wall art, signs, and plaques.
- Prototyping: Model making in plywood or MDF.
- Gift Items: Custom engraved products.
Metal CNC Applications
- Aerospace: Structural parts, brackets, and housings.
- Automotive: Engine components, molds, and fixtures.
- Medical: Implants, surgical tools, and housings.
- Electronics: Heat sinks, connectors, and enclosures.
- Tooling: Jigs, fixtures, and dies.
How to Choose the Right Method
Decision makers should weigh project needs against machine capabilities.
Key Factors
- Material Hardness: Metals need mills; woods use routers.
- Part Complexity: 3D shapes require multi‑axis mills.
- Tolerance Needs: Metal parts often call for tighter limits.
- Budget: Routers start lower, mills cost more upfront.
- Production Volume: High volume favors nested wood layouts or batch metal runs.
Decision Scenarios
- Scenario A: A workshop builds outdoor furniture from cedar panels. A CNC router with dust collection fits the budget and speed needs.
- Scenario B: A shop produces aircraft brackets from titanium. A 5‑axis mill with coolant system meets precision and strength requirements.
Get CNC Machining Services for Metal and Wood
BOYI TECHNOLOGY is here to help. Whether you’re working with metal or wood, we offer professional CNC machining services tailored to your project’s needs. If you’re ready to move forward, simply send us your 3D models, 2D drawings, or any relevant project files to [email protected].
Our experienced engineers will provide you with an instant quote, a clear lead time, and valuable DFM (Design for Manufacturability) feedback—all aimed at helping you streamline the process and make smarter decisions from start to finish.
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Conclusion
Each method suits specific industries and part requirements. Readers can use this guide to select the right machine, tools, and settings for their projects. By understanding these differences, shops can improve quality, cut costs, and boost productivity.
If you’re ready to start your production journey, don’t navigate it alone—consult with an expert. At BOYI, we’re here to help.
FAQ
Not ideally. While some hybrid machines exist, most CNC routers are optimized for softer materials like wood, and CNC mills are designed specifically for metal. Using the wrong machine can damage both the equipment and the material.
CNC wood machining is generally more affordable. Wood CNC routers cost less, require less maintenance, and don’t need coolant systems. Metal machining requires more powerful equipment, specialized tools, and higher operating costs.
This article was written by engineers from the BOYI team. Fuquan Chen is a professional engineer and technical expert with 20 years of experience in rapid prototyping, mold manufacturing, and plastic injection molding.
