3 Axis Cnc Milling Machine: Composition, Types, and How It Optimizes Industrial Performance

Types of 3-Axis CNC Milling Machines

A 3-axis CNC milling machine provides precise control over movement in three primary directions: the X-axis (left to right), Y-axis (forward and backward), and Z-axis (up and down). This configuration allows the cutting tool to approach the workpiece from multiple angles, enabling the creation of complex 2D and 3D shapes with high accuracy. These machines are widely used in prototyping, manufacturing, and engineering due to their versatility and reliability.

CNC Knee Milling Machines

Also known as vertical milling machines, CNC knee mills feature a vertically oriented spindle and a movable knee that supports the worktable. The Z-axis movement is achieved by raising or lowering the knee, while the X and Y axes are controlled by table movement.

Advantages

• Excellent for prototyping and custom one-off parts
• Simple setup and intuitive operation
• Ideal for small to medium-sized workpieces
• Cost-effective for low-volume production

Limitations

• Limited rigidity due to moving knee structure
• Less suitable for heavy-duty or high-precision applications
• Manual adjustments may be required on older models

Best for: Educational environments, small workshops, rapid prototyping, and hobbyist use

CNC Turret Milling Machines

Turret mills feature a stationary spindle and a table that moves along both X and Y axes, mounted on a turret base. These machines can be configured in vertical or horizontal orientations and are available in universal and non-universal variants.

Advantages

• High versatility in machining operations (slotting, surfacing, drilling, angling)
• Precise positioning and repeatability
• Efficient for complex multi-step operations
• Easy to program using modern CAM software

Limitations

• Non-universal models have limited angular capabilities
• Higher initial investment than knee mills
• Requires skilled operators for optimal performance

Best for: Medium to high-precision manufacturing, job shops, and versatile production environments

CNC Bed Milling Machines

Bed mills are designed with a fixed bed that supports the worktable, providing greater stability and rigidity. Unlike knee mills, the spindle head moves along the Z-axis, while the table moves along the X and Y axes, allowing for more powerful and accurate cuts.

Advantages

• Superior rigidity and vibration resistance
• Ideal for heavy cutting and large workpieces
• Higher accuracy and surface finish quality
• Capable of continuous production runs

Limitations

• Larger footprint and higher cost
• Less portable and more complex to install
• Overkill for simple or small-scale projects

Best for: Industrial manufacturing, aerospace components, and high-volume production

Machine Type	Rigidity	Accuracy	Best Use Case	Workpiece Size
CNC Knee Mill	Moderate	Good	Prototyping, education, small batches	Small to Medium
CNC Turret Mill	High	Very Good	Versatile machining, job shops	Medium
CNC Bed Mill	Very High	Excellent	Industrial production, heavy cutting	Medium to Large

Expert Tip: When selecting a 3-axis CNC milling machine, consider your primary application—knee mills are ideal for learning and small projects, turret mills offer the best balance of flexibility and precision, while bed mills are optimal for industrial-grade production requiring maximum stability and power.

Specifications and Maintenance of 3-Axis CNC Milling Machines

3-axis CNC milling machines are essential tools in modern manufacturing, offering precision, repeatability, and versatility for a wide range of materials and applications. Understanding their key specifications helps in selecting the right machine for your needs, while a consistent maintenance routine ensures long-term reliability, accuracy, and operational efficiency.

Key Technical Specifications

The performance and capabilities of a 3-axis CNC milling machine depend on several critical specifications, which vary based on machine size, intended use, and build quality. These include work envelope dimensions, spindle performance, tooling capacity, and material compatibility.

Worktable Size (X-Y-Z Travel)

The worktable or travel range defines the maximum dimensions of the material that can be machined. Entry-level desktop models may offer as little as 80 x 80 mm, while industrial-grade machines can exceed 2,500 x 1,200 mm in X-Y travel, with Z-axis depths ranging from 100 to 500 mm.

Choosing the appropriate table size depends on your typical workpiece dimensions. Larger tables allow for bigger parts or multiple smaller parts to be machined simultaneously, improving productivity. However, larger machines require more floor space and may consume more power.

Spindle Speed and Power

Spindle speed typically ranges from 2,000 to 24,000 RPM, with higher speeds enabling smoother finishes and faster material removal—especially in softer materials like aluminum, plastic, or wood. High-speed spindles are ideal for detailed engraving and high-precision work.

Spindle power (measured in horsepower or kilowatts) determines the machine’s ability to cut harder materials such as steel or titanium. Machines with higher spindle power can maintain performance under heavy loads without overheating or stalling.

Tooling Capacity and Automatic Tool Changers

Most 3-axis CNC mills support between 20 and 120 cutting tools, depending on whether they feature a tool changer system. Manual setups may require operator intervention for tool changes, while automated tool changers (ATCs) improve efficiency and enable unattended operation.

Tool holders must be compatible with standard shank sizes (e.g., ER-20, ER-32, or ISO tapers), and proper tool management software helps track tool life and usage. Using the correct tool for each material improves surface finish and extends tool life.

Material Compatibility

3-axis CNC machines are capable of machining a wide variety of materials, including aluminum, steel, brass, plastics (such as ABS, polycarbonate), wood, MDF, foam, and composites. The machine’s rigidity, spindle power, and feed rate determine its suitability for harder materials.

For example, soft materials like foam or wood require lower clamping force and higher spindle speeds, whereas steel demands slower speeds, higher torque, and robust fixturing. Coolant or lubrication systems are often necessary when working with metals to prevent overheating and tool wear.

Specification	Typical Range	Application Notes
Worktable Size (X-Y)	80 × 80 mm to 2,500 × 1,200 mm	Choose based on part size; larger tables suit batch production
Spindle Speed	2,000 – 24,000 RPM	Higher speeds for plastics/wood; lower speeds for steel
Tool Capacity	1 – 120 tools	ATC-equipped machines allow automated multi-tool jobs
Axis Resolution	0.001 – 0.01 mm	Higher resolution enables tighter tolerances and fine detail

Essential Maintenance Practices

Regular maintenance is crucial for preserving accuracy, prolonging component life, and minimizing unplanned downtime. A well-maintained CNC machine delivers consistent results and reduces the risk of costly repairs.

Lubrication of Moving Components: Guide rails, ball screws, linear bearings, and rotary encoders must be lubricated regularly using manufacturer-recommended grease or oil. Proper lubrication reduces friction, prevents wear, and ensures smooth motion across all three axes.

Cleaning of Ball Screws and Rails: Dust, metal chips, and coolant residue can accumulate on ball screws and linear guides, leading to binding or inaccurate positioning. Use a soft brush and lint-free cloth to clean these components during scheduled maintenance intervals.

Inspection and Replacement of Cutting Tools: Dull, chipped, or worn tools compromise cut quality and increase stress on the spindle. Inspect tools before each job and replace them according to usage logs or visible wear. Store tools in a dry, organized manner to prevent damage.

Worktable and Fixture Maintenance: Keep the worktable clean and free of debris. Check T-slots or vacuum fixtures for obstructions. Ensure clamps and vises are functioning properly and securely hold the workpiece during operation.

Machine Calibration and Alignment: Over time, mechanical components may shift due to vibration or thermal expansion. Regularly calibrate the machine using dial indicators or laser alignment tools to maintain positional accuracy and squareness across all axes.

Coolant and Chip Management: If equipped with a coolant system, ensure it is clean and properly mixed. Empty and clean chip trays regularly to prevent buildup that could damage moving parts or affect machine balance.

Important: Always follow the manufacturer’s maintenance schedule and use only approved lubricants, tools, and replacement parts. Skipping maintenance or using incorrect components can lead to premature wear, reduced accuracy, or catastrophic failure. Proper care not only extends the lifespan of your CNC machine but also ensures operator safety and consistent production quality.

Applications of 3-Axis CNC Milling Machines Across Industries

Since their introduction, 3-axis CNC milling machines have revolutionized manufacturing and fabrication processes across a wide range of industries. These versatile machines offer precise, repeatable, and automated cutting capabilities along three linear axes—X, Y, and Z—making them ideal for creating complex geometries from metals, plastics, wood, and composites. Their widespread adoption is due to their reliability, cost-effectiveness, and adaptability to both prototyping and production environments.

Key Advantage: The simplicity and precision of 3-axis CNC milling make it a foundational technology in modern manufacturing, capable of producing high-tolerance components with excellent surface finishes and consistent repeatability.

Manufacturing Industry

3-axis CNC milling machines are a cornerstone in general manufacturing, particularly in metal and woodworking facilities. They enable rapid production of custom parts, prototypes, and tooling for a variety of consumer and industrial products.

• Used to fabricate brackets, enclosures, panels, bases, frames, and structural assembly components
• Supports rapid prototyping for product development in electronics, home appliances, and industrial equipment
• Produces custom signage, furniture, cabinetry, and decorative woodwork with high precision
• Ideal for batch production of interchangeable parts with tight tolerances

Note: These machines are especially valuable in small-to-medium enterprises where flexibility and low setup costs are critical.

Construction & Architecture

In the construction sector, 3-axis CNC mills play a vital role in creating custom architectural elements and molds for concrete casting, enabling intricate designs that would be difficult or impossible to achieve manually.

• Produces custom window frames, door trims, balustrades, stair components, and ornamental wood/metal features
• Creates high-precision molds for precast concrete elements such as wall panels, foundation pads, and façade details
• Enables replication of historical architectural details for restoration projects
• Facilitates rapid fabrication of formwork and jigs for on-site construction

Pro tip: CNC-machined molds ensure dimensional accuracy and smooth finishes, reducing labor and material waste in concrete pouring.

Automotive Industry

From prototyping to production, 3-axis CNC milling supports the automotive industry by manufacturing critical components and specialized tooling with consistent quality.

• Produces engine blocks, transmission housings, suspension components, and intake manifolds
• Fabricates interior trim pieces, dash components, and custom accessories
• Used for creating composite molds and lightweight chassis parts
• Essential for manufacturing jigs, fixtures, and gauges used in assembly lines and quality control

Critical use: Rapid tooling development allows automakers to iterate designs quickly during R&D phases.

Aerospace Industry

The aerospace sector relies on 3-axis CNC milling for producing lightweight, high-strength components and precision tooling required for aircraft assembly.

• Mills structural brackets, mounting plates, and housing units from aluminum, titanium, and high-performance alloys
• Produces jigs and fixtures for wing assembly, fuselage alignment, and avionics installation
• Creates precision components for landing gear systems and cabin interiors
• Supports customization of drone and UAV parts for specialized missions

Technical note: While 5-axis machines handle complex contours, 3-axis systems remain cost-effective for flat or prismatic aerospace components.

Defense & Weaponry

3-axis CNC milling is extensively used in defense manufacturing for producing firearm components, accessories, and engraved markings with military-grade precision.

• Manufactures receivers, barrels, triggers, and bolt carriers for rifles and machine guns
• Produces optic mounts, rail systems, and suppressor components
• Enables precise engraving of serial numbers, logos, and tactical markings
• Supports rapid prototyping of new weapon designs and custom modifications

Security note: Strict regulatory compliance (e.g., ITAR) governs the use of CNC equipment in firearm production.

Medical Devices & Robotics

In high-precision fields like medical technology and robotics, 3-axis CNC machines produce intricate components that demand exacting tolerances and biocompatible materials.

• Manufactures surgical instruments, implant prototypes, and diagnostic equipment housings
• Produces robotic joints, actuators, sensor mounts, and control enclosures
• Enables machining of titanium and medical-grade plastics for prosthetics and implants
• Supports rapid development of lab automation devices and microfluidic systems

Quality focus: Cleanroom-compatible machining and ISO-certified processes ensure medical device safety and reliability.

Jewelry & Watchmaking

The jewelry and horology industries leverage 3-axis CNC milling to create intricate, high-detail designs in precious metals and alloys with exceptional precision.

• Produces rings, pendants, bracelets, and custom jewelry pieces from gold, silver, and platinum
• Engraves fine patterns, logos, and personalized inscriptions with micron-level accuracy
• Manufactures watch cases, bezels, dials, and movement bridges
• Allows for rapid prototyping of new designs before mass casting

Design advantage: CNC milling enables complex geometries and textures that enhance aesthetic appeal and wearability.

Textile Industry

3-axis CNC milling supports textile manufacturing by producing precision tooling and machine components essential for weaving, spinning, and knitting operations.

• Creates molds and dies for textile rollers, guides, and tensioners
• Produces components for looms, spinning frames, and knitting machines
• Ensures dimensional accuracy in parts that affect fabric quality and production speed
• Facilitates repair and replacement of obsolete machine elements

Efficiency gain: CNC-machined parts reduce downtime and improve consistency in textile production lines.

Industry	Common Materials	Typical Components	Key Benefits
Manufacturing	Aluminum, Steel, Wood, Plastics	Brackets, Panels, Enclosures	High repeatability, fast turnaround
Construction	Wood, MDF, Foam, Aluminum	Window Frames, Molds, Decorative Elements	Custom design capability, reduced labor
Automotive	Cast Iron, Aluminum, Composites	Engine Parts, Chassis, Fixtures	Precision fit, rapid prototyping
Aerospace	Titanium, Aluminum Alloys	Structural Brackets, Jigs	Lightweight, high-strength output
Weaponry	Steel, Stainless Steel, Aluminum	Firearm Receivers, Mounts, Sights	Consistent quality, traceability
Medical/Robotics	Titanium, PEEK, Stainless Steel	Implants, Surgical Tools, Actuators	Biocompatible, high precision
Jewelry/Watchmaking	Gold, Silver, Platinum, Brass	Rings, Watches, Engravings	Intricate detail, customization
Textiles	Brass, Aluminum, Engineering Plastics	Rollers, Guides, Machine Parts	Wear resistance, dimensional accuracy

Additional Considerations for Optimal Use

• Material Compatibility: Ensure proper tooling and cutting parameters for each material to maximize tool life and surface finish
• Software Integration: Use CAD/CAM software to streamline design-to-production workflows and minimize errors
• Maintenance: Regular calibration and spindle care ensure long-term accuracy and performance
• Skill Requirements: Operators should be trained in G-code, machine setup, and workholding techniques
• Scalability: 3-axis machines can be integrated into automated cells with robotic loaders for higher throughput

Expert Insight: While 5-axis CNC machines offer greater flexibility for complex geometries, 3-axis milling remains the most cost-effective and widely applicable solution for the majority of industrial machining tasks. Its balance of precision, speed, and affordability makes it an indispensable tool across virtually every manufacturing sector.

How to Choose a 3-Axis CNC Milling Machine: A Comprehensive Buyer’s Guide

3-axis CNC milling machines are among the most versatile and widely used tools in modern manufacturing, prototyping, and fabrication. Their ability to move along the X, Y, and Z axes enables precise cutting, shaping, and drilling of various materials, making them ideal for industries ranging from aerospace to woodworking. However, selecting the right machine requires careful evaluation of your operational needs, technical specifications, and long-term support. This guide breaks down the key factors to consider when purchasing a 3-axis CNC milling machine to ensure optimal performance, durability, and return on investment.

Important Note: A poorly chosen CNC machine can lead to production delays, increased maintenance costs, and compromised part quality. Take time to assess your requirements thoroughly before making a purchase decision.

Key Factors to Consider When Choosing a 3-Axis CNC Milling Machine

1. Conduct a Thorough Needs Analysis

   Before evaluating machines, clearly define your machining goals. Ask yourself:

   • What materials will you primarily machine? (e.g., aluminum, steel, plastics, wood)
   • What is the typical size and thickness of your workpieces?
   • How complex are your designs? (e.g., simple 2D profiles vs. intricate 3D contours)
   • What level of precision (tolerance) and surface finish quality is required?
   • What is your expected production volume? (low-volume prototyping vs. high-volume production)

   Understanding these parameters will help narrow down machine capabilities. For example, high-precision aerospace components require tighter tolerances and higher rigidity than woodworking applications.

2. Evaluate the Work Area and Machine Capacity

   The work envelope determines the maximum size of parts you can produce. Key considerations include:

   • Table size: Ensure the machine table can accommodate your largest workpiece with room for fixturing.
   • Travel (stroke): Check the X, Y, and Z-axis travel distances to confirm they meet your dimensional needs.
   • Load capacity: The table must support the weight of your workpiece and fixtures without deflection.
   • Clearance: Verify vertical clearance for tooling and workholding, especially when using tall vises or rotary tables.

   Tip: It’s wise to choose a machine with slightly larger capacity than your current needs to allow for future growth.

3. Assess Spindle Performance and Specifications

   The spindle is the heart of the CNC milling machine, directly impacting cutting speed, material compatibility, and surface finish. Key spindle factors include:

   • Spindle speed (RPM): Higher speeds (10,000–24,000 RPM) are ideal for small tools and non-ferrous materials like aluminum or plastics.
   • Motor power (HP/kW): Higher power (5–15 HP+) is essential for heavy cutting in steel or titanium.
   • Spindle taper: Common tapers include BT30, BT40, and CAT40—ensure compatibility with your tooling inventory.
   • Cooling system: Look for air or through-spindle coolant options to extend tool life and improve chip removal.
   • Runout and accuracy: High-quality spindles maintain minimal runout (< 0.0002") for precision machining.

   For mixed-use applications, consider a machine with variable speed control and automatic tool changing (ATC) capability.

4. Select the Right Milling Cutters and Tool Compatibility

   The effectiveness of your CNC machine depends on compatible, high-quality tooling. Consider:

   • Type of cutters: End mills (square, ball-nose, corner radius), face mills, slot drills, and specialty cutters for specific tasks.
   • Material compatibility: Carbide, HSS, or coated tools for different materials and cutting conditions.
   • Tool holder system: Ensure the machine supports common holders like ER collets, hydraulic chucks, or shrink-fit systems.
   • Tool library and management: Advanced machines allow digital tool presetting and automatic tool length measurement.

   Choose a machine that supports a wide range of tooling options to maximize flexibility across different jobs.

5. Review Software and Control System

   The control system is the machine’s brain, dictating ease of use, programming flexibility, and integration potential. Evaluate:

   • Control interface: Look for intuitive, touchscreen-based controls like Fanuc, Siemens, or Haas CNC controls.
   • Software compatibility: Ensure the machine works with your preferred CAD/CAM software (e.g., Fusion 360, Mastercam, SolidWorks).
   • Programming options: Support for G-code, conversational programming, and probing cycles enhances usability.
   • Connectivity: USB, Ethernet, and Wi-Fi options facilitate file transfer and remote monitoring.
   • Automation readiness: Machines with open APIs or PLC integration are better suited for future automation.

   A user-friendly control system reduces training time and minimizes programming errors.

6. Choose a Reputable Brand with Strong Service Support

   The manufacturer and service provider significantly impact machine longevity and uptime. Consider:

   • Brand reputation: Established brands like Haas, DMG MORI, Tormach, and FANUC are known for reliability and precision.
   • Warranty and technical support: Look for at least a 1-year warranty and access to responsive technical assistance.
   • Installation and training: Professional setup and operator training ensure optimal machine performance from day one.
   • Parts availability: Quick access to spare parts and consumables reduces downtime.
   • Local service network: Proximity to certified technicians ensures faster repairs and maintenance.

   Don’t overlook post-purchase support—ongoing service can be more valuable than initial price savings.

Selection Factor	Key Questions to Ask	Ideal For	Potential Trade-offs
Needs Analysis	What materials, sizes, and tolerances are typical?	All users	Over- or under-specifying machine capabilities
Work Area	Will the machine handle current and future part sizes?	High-volume or large-part manufacturers	Larger machines require more floor space and cost more
Spindle Performance	Does RPM and power match your cutting needs?	Metalworking, high-speed machining	High-power spindles consume more energy and require cooling
Tooling Compatibility	Can it use your existing or preferred tooling?	Multi-material or high-flexibility shops	Proprietary systems may limit tool choices
Control System	Is it easy to program and integrate with your workflow?	Small shops, beginners, automation users	Advanced controls may have a steeper learning curve
Brand & Service	Is support available locally and promptly?	All users, especially production environments	Premium brands may have higher upfront costs

Expert Tip: Whenever possible, request a live demonstration or sample part run from the supplier. This allows you to evaluate machine performance, surface finish quality, and control responsiveness before committing to a purchase.

Additional Recommendations

• Consider future scalability—choose a machine that can be upgraded with probes, tool changers, or automation.
• Budget for additional costs: tooling, workholding, software licenses, training, and installation.
• Read customer reviews and consult industry forums to gauge real-world user experiences.
• Ask about financing options or leasing programs to manage capital expenditure.
• Ensure the machine meets safety standards (e.g., CE, OSHA) and includes emergency stops and guarding.

Selecting the right 3-axis CNC milling machine is a strategic decision that impacts productivity, part quality, and operational efficiency. By carefully analyzing your needs, comparing technical specifications, and prioritizing reliable support, you can invest in a machine that delivers long-term value and performance. When in doubt, consult with application engineers or industry experts to guide your decision-making process.

3-Axis CNC Milling Machine: Frequently Asked Questions

Q1: What materials can a 3-axis CNC machine cut?

A 3-axis CNC milling machine is a versatile manufacturing tool capable of machining a wide range of materials across multiple industries, including aerospace, automotive, woodworking, and prototyping. The machine's spindle moves along three linear axes—X (left-right), Y (front-back), and Z (up-down)—allowing it to precisely remove material from a stationary workpiece.

Commonly Machined Materials:

• Metals: Aluminum (most common due to its softness and lightweight), brass, copper, carbon steel, stainless steel, tool steel, and titanium (with appropriate tooling and cooling).
• Plastics: Acrylic (PMMA), polycarbonate (Lexan), ABS, nylon, POM (Delrin), PVC, HDPE, and polyethylene.
• Wood & Composites: Hardwood, softwood, plywood, MDF, particleboard, and laminates.
• Other Materials: Foam (ideal for molds and prototypes), wax (used in investment casting), rubber, and circuit boards (FR4).

Material selection depends on several factors, including tool hardness, spindle speed, feed rate, cooling methods, and fixturing. Softer materials like wood and acrylic require lower cutting forces and can be machined at higher speeds, while harder metals demand rigid setups, carbide tooling, and proper lubrication or coolant to prevent overheating and tool wear.

Q2: What file formats does a 3-axis CNC machine use?

Modern 3-axis CNC machines rely on digital design and programming files to control toolpaths and machining operations. Unlike traditional manual milling machines that used physical templates or simple drill jigs, CNC systems operate based on coded instructions derived from CAD (Computer-Aided Design) and CAM (Computer-Aided Manufacturing) software.

Primary File Types Used:

• G-code (.nc, .gcode, .tap): The most essential file format—it contains the actual machine instructions (tool movements, speeds, feeds, spindle on/off) generated by CAM software. This is the final code uploaded to the CNC controller.
• DXF (.dxf): A 2D vector format commonly used for flat designs, engravings, or simple profiles. Often imported into CAM software to generate toolpaths for 2.5D operations.
• DWG (.dwg): Native AutoCAD format, similar to DXF but with more advanced features. Requires conversion or direct CAM compatibility.
• STEP/STP (.step): A 3D CAD format used to transfer solid models between different software platforms. Ideal for complex 3D parts that need full 3-axis contouring.
• IGES (.igs): An older 3D interchange format, still supported by many systems for geometry transfer.
• SLD (SolidWorks), PRT (Siemens NX), IPT (Inventor): Native CAD files that can be directly imported into compatible CAM software for programming.

The typical workflow involves designing a part in CAD software, exporting or importing it into CAM software, defining toolpaths, selecting cutting tools, and generating G-code tailored to the specific CNC machine and material. This ensures precision, repeatability, and efficient material removal.

Q3: What is the difference between a 2D and 3D CNC machine?

The terms "2D" and "3D" in CNC machining refer to the complexity of the toolpath and the number of axes used for cutting, rather than the physical structure of the machine itself. Most modern CNC mills are 3-axis machines, but they can perform both 2D and 3D operations depending on programming and toolpath strategy.

Feature	2D CNC Machining	3D CNC Machining
Axis Movement	Uses X and Y axes; Z-axis only for depth control (e.g., pocketing or drilling).	Full simultaneous movement across X, Y, and Z axes for complex contours.
Toolpath Complexity	Flat, planar cuts—ideal for outlines, engravings, and 2.5D features like slots and holes.	Multi-dimensional surfaces such as molds, sculpted parts, and organic shapes.
Common Applications	Signage, PCB routing, sheet cutting, joinery, and simple part profiling.	Prototypes, injection molds, aerospace components, artistic sculptures, and custom enclosures.
Software Requirements	Basic CAM software with 2D or 2.5D capabilities.	Advanced CAM software with 3-axis or 3+2 axis programming (e.g., Fusion 360, Mastercam).
Machining Time	Generally faster due to simpler toolpaths and higher feed rates.	Slower, as the tool must follow intricate paths with smaller stepovers and depths.

While a 3-axis CNC machine is physically capable of 3D work, it’s often used for 2D tasks when simplicity and speed are priorities. True 3D machining requires careful planning of tool engagement, surface finish, and tool deflection to avoid chatter and inaccuracies. For even more complex geometries, 4-axis and 5-axis CNC machines are used, allowing rotation of the part or tool for access to multiple sides without re-fixturing.