3-axis and 5-axis machine tools and their machining processes: working principles, advantages, disadvantages and applications

Regardless of type, CNC machine tools offer high manufacturing precision, diverse functions, and a wide variety of models to meet the needs of different industries. 3-axis and 5-axis CNC machine tools are currently the two most common types on the market, each with its own advantages, disadvantages, and application scenarios. Their ultimate goal is to manufacture high-precision parts, but their functions, application directions, and costs differ.

This article will focus on three-axis and five-axis CNC machine tools. These two types of CNC machine tools each have their unique advantages and challenges. A deeper understanding of these machine tools’ details, advantages and limitations, machinable materials, applications, and how they can influence your decisions based on your manufacturing needs will be crucial.

Basic working principles of 3-axis and 5-axis CNC machine tools

In reality, whether it’s a 3-axis or 5-axis machine tool, the working principle is the same. The operation of a CNC machine tool relies entirely on computer numerical control and coding. It primarily uses pre-programmed software to control the machine tool’s operation and movement.

The basic working principle of this machine tool is as follows: A computer translates a digital design into a physical object through a CNC machine tool. The computer controller, motors, and tools constitute the basic components of the CNC machine tool. The computer controller uses G-code (a special programming language) to interpret the design and then causes the motors to follow a predetermined path when moving the machining tool.

Detailed programming is crucial for the control tools and built-in components. When the operator provides the machine with the correct code and instruction set, the machine performs a specific task. The machine, in turn, interprets the code and executes the task accordingly. Automation ensures the machine continues performing the task until it is fully completed. Most importantly, this type of equipment eliminates the need for manual operation by the operator, saving time and effort.

Currently, they are used in many different fields because they enable faster production speeds, higher precision capabilities, and greater geometric complexity when producing any given part shape, among other benefits.

Differences between control axes of 3-axis and 5-axis CNC machine tools

Regardless of the number of axes, the core technology of a CNC machine tool lies in controlling the direction of axis movement and the movement of the cutting tool. In a standard CNC machine tool, three axes are fundamental, mainly controlling the X-axis (movement from left to right), Y-axis (forward and backward movement), and Z-axis (up and down movement).

An axis is an imaginary line used to measure coordinates; the term is used to define a point in a spatial dimension. Horizontal and vertical planes are defined using the X and Y axes, while three-dimensional depth is defined using the Z axis. In machinery, the Z-axis refers to the rotational axis. Typically, linear axes emphasize the direction and movement of a machine tool; in a three-axis machine, the spindle moves up, down, and left/right; in a five-axis machine, it can move up and down, left and right, and has two rotational motions.

Therefore, a three-axis CNC machine tool can drill holes in any workpiece to create three-dimensional objects. However, it cannot handle any complex or advanced designs. When machining parts with complex designs is required, a five-axis machine is needed because it adds axes such as the A-axis (rotation around the X-axis), B-axis (rotation around the Y-axis), and C-axis (rotation around the Z-axis), allowing for control of more cutting directions and enabling more complex machining operations.

What are the core components of 3-axis and 5-axis CNC machine tools?

Although 3-axis and 5-axis CNC machine tools differ in the number of axes, their working principles are the same. The main difference lies in the cutting operations performed by different key components during operation. Below is a list of the main components of a common CNC machine tool and their respective functions:

Computer controller	It acts as the brain of the CNC machine tool, processing G-code and sending commands to the motors. Key technical parameters are:
Processor speed	This determines the speed at which G code is interpreted (in GHz).
Memory capacity	It affects the complexity of executable programs (in MB or GB).
motor	It is responsible for driving the machine to move along the X, Y, and Z axes. The motor can be a stepper motor or a servo motor.
drive system	The system consists of a ball screw, linear guide, and belt, and is used to transmit motion from the motor to the machine tool.
machine tool	Components that come into contact with raw materials and are subjected to cutting, drilling or other processing operations.
workbench	A platform for placing unprocessed materials.
Sensors and feedback systems	Accuracy and safety are ensured by providing real-time data on positioning and operations.

The main differences between 3-axis and 5-axis machine tools and machining

Understanding the complexities and limitations of different CNC machine tools is essential for ensuring the optimal balance between cost, time, and quality in parts machining. Due to the complexities associated with fixtures and processes, the cost of using the wrong machine for a project can be significantly higher, especially with 3-axis and 5-axis machine tools. Therefore, understanding the key differences between 3-axis and 5-axis machining is crucial. Doing so ensures that the best machine is selected for any given project without compromising fundamental quality parameters. Below are the main differences between 3-axis and 5-axis machining.

Processing direction	Three-axis machining is limited to movement in the X, Y, and Z directions, while five-axis machining adds two rotary axes, A and C, allowing the tool to contact the workpiece from multiple angles.
Processing capacity	Three-axis machining is suitable for planar surfaces and simple contours, while five-axis machining can cover the machining needs of complex curved surfaces, deep cavities, and multi-angle parts.
Machining accuracy	Five-axis machining can complete the machining process in one setup, reducing the errors caused by multiple setups, and thus has higher machining accuracy, while three-axis machining may require multiple setups.
Cost and maintenance	Three-axis machining has lower costs and simpler equipment, while five-axis machining has higher equipment costs and maintenance expenses, requiring a higher budget investment.
Programming difficulty	Programming three-axis machine tools is relatively simple and suitable for basic machining needs; while programming five-axis machining is complex and requires a high level of expertise from technicians.

The differences in operation and programming between 3-axis and 5-axis machine tools in CNC design.

In CNC machine tool design and programming, the differences between three-axis and five-axis machine tools mainly lie in machine tool kinematics, operational complexity, toolpath generation logic, and overall programming flow. These differences directly affect part design strategies, CAM programming workload, and actual workshop operations. Below is a summary of the differences in programming for these two types of machine tools.

Programming a 3-Axis Machine Tool

Method: CAD/CAM Design: Create a 3D model of the part in CAD software.

Toolpath Generation: In CAM software, generate toolpaths that move the cutting tool along X, Y, and Z axes. Typical operations include:

• Contouring

• Pocketing

• Drilling

• Facing

• 2.5D machining

Setup Definition: Define part orientation, fixture locations, and work offsets (usually G54-G59).

Post-Processing: Convert the CAM toolpaths into machine-specific G-code.

Verification: Simulate the program to check for collisions and proper material removal.

Execution: Load the program on the CNC machine and run, adjusting feed and speed as necessary.

Programming a 5-Axis Machine Tool

Method: CAD/CAM Design: Create a 3D or freeform model of the part.

Toolpath Generation: In 5-axis CAM software, generate toolpaths that include:

• Linear and rotary axis motion

• Tool tilt and lead angles
• Full or indexed 5-axis machining

Full or indexed 5-axis machiningSetup Definition: Define the workpiece orientation and rotary axis configuration. Decide whether the part will be machined in 3+2 mode (rotary axes index, linear axes cut) or simultaneous 5-axis mode (all axes move together).

Post-Processing: Use a 5-axis-specific post-processor to translate tool vectors into rotary axis commands (A, B, or C axes). Must handle singularities, axis limits, and TCP (Tool Center Point) calculations.Verification: Simulate full 5-axis motion to prevent collisions, over-travel, or sudden rotary axis moves.

Execution: Load the program onto the machine, monitor rotary axis behavior, and adjust cutting parameters carefully.

Comparison of the advantages and disadvantages of 3-axis and 5-axis CNC machine tools

The number of additional axes available in CNC machining is the main factor distinguishing between 3-axis and 5-axis methods, and the number of axes leads to further subtle differences in machine tools. The following is a comparison of the advantages and disadvantages of the two machine tools.

Machine Type	Advantages	Disadvantages
3-Axis CNC Machine Tools	• Lower equipment purchase and maintenance cost • Simple machine structure and stable operation • Easier programming and operation • Wide availability of operators and CAM support • Suitable for most prismatic and flat parts	• Limited ability to machine complex geometries • Multiple setups required for multi-face machining • Lower efficiency for complex parts • Accumulated positioning errors from repeated clamping • Restricted tool access and cutting angles
5-Axis CNC Machine Tools	• Capable of machining complex and freeform geometries • Single-setup machining for multiple faces • Higher machining accuracy and consistency • Better surface finish and longer tool life • Higher efficiency for complex and high-precision parts	• High initial investment and maintenance cost • More complex programming and setup • Higher requirements for CAM software and post-processors • Requires skilled operators and engineers • Higher risk of collision if improperly programmed

Industries and applications of 3-axis and 5-axis CNC machining

CNC machine tools, regardless of the number of axes, can be widely used in many industrial fields. Below are some common industries that 3-axis and 5-axis CNC machine tools serve and the corresponding parts they manufacture.

Industry Sector	Parts Typically Machined by 3-Axis CNC	Parts Typically Machined by 5-Axis CNC
Automotive	Brackets, engine covers, transmission housings, mounting plates, fixtures	Cylinder heads, turbocharger housings, suspension knuckles, complex powertrain components
Aerospace	Structural brackets, mounting plates, tooling components	Turbine blades, impellers, blisks, airframe structural parts
Medical Devices	Instrument housings, surgical tool handles, equipment brackets	Orthopedic implants, dental implants, bone plates, complex surgical instruments
Electronics & Electrical	Heat sinks, enclosures, connector plates, chassis components	Precision connectors, RF components, complex electronic housings
Industrial Equipment	Machine bases, covers, flanges, shafts, standard fixtures	Precision gear housings, hydraulic manifolds, multi-port valve bodies
Mold & Die	Simple mold bases, inserts, cores with straight features	Complex mold cores, cavities with freeform surfaces, high-precision die components
Energy & Power	Mounting components, pump housings, structural supports	Impellers, turbine components, compressor blades
Consumer Products	Frames, panels, casings, decorative metal parts	Ergonomic housings, complex aesthetic parts, high-end product shells

A comprehensive comparison of 3-axis and 5-axis CNC machine tools and their machining information.

The above article has briefly described the basic information about 3-axis and 5-axis machine tools and related machining principles. Below, we will conduct a comprehensive comparison of the two.

Comparison Dimension	3-Axis CNC Machine Tools	5-Axis CNC Machine Tools
Machine Configuration	Linear movement along X, Y, and Z axes only. Tool orientation remains fixed relative to the workpiece.	Linear movement along X, Y, Z axes plus two rotational axes (A/B/C), enabling continuous tool orientation changes.
Machining Capability	Suitable for simple to moderately complex geometries with features accessible from a single direction.	Capable of machining highly complex geometries, undercuts, and multi-angle features in a single setup.
Setup and Fixturing	Requires multiple setups and re-clamping for multi-face machining, increasing fixture complexity.	Typically completes multi-face machining in one setup, significantly reducing fixturing and alignment requirements.
Machining Accuracy	Accuracy is affected by cumulative repositioning errors due to multiple setups.	Higher overall accuracy due to fewer setups and continuous tool orientation control.
Surface Quality	Surface finish may vary between faces due to tool repositioning and setup changes.	Superior surface finish, especially on complex contours, due to optimal tool engagement angles.
Programming Complexity	Relatively simple programming; widely supported by basic CAM systems and operators.	More complex programming requiring advanced CAM software and skilled programmers.
Machining Efficiency	Lower efficiency for complex parts due to repeated setups and non-cutting time.	Higher efficiency for complex parts by reducing setups and enabling continuous machining paths.
Tool Life	Tool wear may be uneven due to limited tool orientation and suboptimal cutting angles.	Improved tool life through consistent cutting angles and reduced tool load.
Equipment Cost	Lower machine purchase cost and maintenance expenses.	Significantly higher capital investment and maintenance costs.
Typical Applications	Flat or prismatic parts, simple brackets, plates, housings, and standard mechanical components.	Aerospace, medical, automotive, and mold components requiring complex surfaces and high precision.
Operator Skill Requirements	Moderate skill level; easier training and operation.	Higher skill requirements for operation, setup, and process optimization.
Overall Advantages	Cost-effective, easy to operate, flexible for general machining tasks.	High precision, reduced setups, superior surface quality, and capability for complex parts.
Overall Disadvantages	Limited geometric capability and lower efficiency for complex parts.	High cost, complex programming, and greater dependence on skilled personnel.

Should a 3-axis or 5-axis CNC machine tool be chosen when actually manufacturing parts?

When determining which machine tool to use to manufacture parts, the decision should be based on a structured assessment of part requirements, cost constraints, and production targets, not just the performance of the machine tool. I have summarized the following factors for reference.

Part geometry and design complexity

The primary and most critical factor is the part geometry. If the part features only need to be machined in one or two directions, a three-axis machine tool is usually sufficient. However, for parts containing complex freeform surfaces, deep cavities, undercuts, or features requiring multiple machining angles, five-axis machining is more suitable.

Tolerance, precision and surface quality requirements

Complex parts are typically manufactured using three-axis machine tools because the need for multiple clamping operations can accumulate positioning errors, making it difficult to maintain strict tolerances. Therefore, for parts that require high-precision positioning between multiple surfaces or to achieve excellent surface finish on curved surfaces, five-axis machining centers offer the advantages of single clamping, continuous machining, and optimal tool orientation, making them more suitable for machining complex parts.

Production volume and cost sensitivity

For medium-to-high volume, low-complexity parts, three-axis machining is the most cost-effective option. Conversely, for medium-to-low volume, high-complexity, or high-value-added custom parts, five-axis machining is more suitable. This is because it can reduce total manufacturing costs by reducing the number of setups, shortening delivery cycles, and reducing scrap and rework.

Delivery cycle and process efficiency

High-volume custom manufacturing projects typically prioritize shortening lead times. Three-axis machining centers offer faster programming and easier scheduling, but complex parts requiring multiple setups can lead to excessively long overall machining cycles. Five-axis machining centers can integrate multiple operations into a single setup, significantly improving machining efficiency and delivery speed for complex parts.

Engineering Resources and Risk Control

Five-axis machining requires advanced CAM software, precise post-processors, and experienced programmers and operators. If these resources are limited, the risk of programming errors or collisions increases. In such cases, for simpler parts, a well-designed three-axis machining process may be a safer option.

Customized CNC machining solutions for different axes for your business

We can provide customized CNC machining solutions for your company, and our services can be tailored to different manufacturing requirements. Our design team, together with our engineering department, collaborates with clients at every stage to identify your specific needs, thereby delivering a final product that maximizes productivity while minimizing downtime. Therefore, we can provide robust support throughout your project lifecycle, from initial consultation and design to installation, plus ongoing maintenance. You can rely on our knowledge and modern equipment to achieve outstanding performance and reliability for all your CNC machining needs.

Conclusion

If you’re struggling to decide whether to use a 3-axis or 5-axis CNC machine for your custom parts project, you’ll find that neither is inherently superior when comparing them. There’s no single, standard approach to choosing the best machine for your project, as many factors need to be considered. You’ll need to consider your production needs, production targets, production volume, existing expertise and skill levels, and budget. This article explains the basic working principles of 3-axis and 5-axis CNC machine tools, their differences, applicable industries, and considerations when making a selection.

FAQ

What are the main differences between three-axis, four-axis, and five-axis CNC machine tools?

The main difference between these machines lies in the number of directions (or axes) they can move or control. A 3-axis CNC machine tool moves in three directions: X, Y, and Z. A 4-axis machine tool adds rotational motion around one of these axes. A 5-axis machine offers even greater flexibility, enabling movement in five different directions. This provides higher precision and allows for the creation of complex shapes in less time.

FAQ