CNC machining has become one of the workshops’ most critical manufacturing processes worldwide. Handheld machines have advanced to highly sophisticated computerized machines (CNC). Different types of CNC machining require more excellent CNC programming preparation time to accommodate complex rotatory movement but allow us to process one workpiece on all five sides during one operation.

CNC machining technology has evolved to include 3-axis, 4-axis, and 5-axis machines, which enable helical machining. These machines use 2 of the three possible rotation axes, depending on the type of machine. CNC machines have undergone several evolutions to meet the increasingly complex requirements of multiple industries.

Through this article, we will learn the differences between 3 Axis, 4 Axis, and 5 Axis CNC Machining and their advantages and disadvantages. Let’s go!

What is 3-Axis CNC Machining?

3-axis CNC machining refers to a computer-controlled process that uses three axes of motion to manufacture parts or products. The three axes are the X-axis(horizontal axis), Y-axis(vertical axis), and Z-axis(depth axis).

Here are some examples of 3-axis CNC machines:

1. 3 Axis CNC milling machines use rotary cutting tools to remove material from a workpiece. They are commonly used to produce automotive, aerospace, and medical parts.

2. 3 Axis CNC routers: These machines use rotating cutting tools to carve, cut, or shape materials such as wood, plastic, and metal. They are commonly used in the woodworking and signage industries.

3. 3 Axis CNC lathes: These machines are used for turning operations, which involve rotating a part against a cutting tool to create cylindrical shapes. They are commonly used to produce automotive, aerospace, and medical components.

4. 3 Axis CNC plasma cutters: These machines use a plasma torch to cut through electrically conductive materials such as steel, aluminum, and brass. They are commonly used in the metal fabrication industry.

5. 3 Axis CNC drilling machines: These machines are designed to drill holes in metal and plastic. They are commonly used in the electronics and automotive industries.

Manufacturing Uses for 3-Axis Machines

-Drilling holes

-Machining slots

-Rounding corners(Cutting sharp edges)

-Cutting more superficial features and geometries

What is 4-Axis CNC Machining?

4-axis CNC machines are advanced manufacturing machines that can move the cutting tool or the workpiece in four axes (X, Y, Z, and an additional rotational axis). The fourth axis of rotation allows for more complex and precise cutting and shaping of parts. Here is the introduction to 4-axis CNC milling and turning machines:

1. 4 Axis CNC milling machines: These milling machines can have a rotary table or a tilting head to add the fourth axis of rotation. The workpiece can be rotated with a rotary table while the cutting tools move in the other three axes. With a tilting tool head, the cutting tool can be tilted to an angle, allowing for more intricate cuts.

2. 4 Axis CNC turning machines: These machines can have a sub-spindle or a live tooling system to add the fourth axis of rotation. With a sub-spindle, the workpiece can be transferred between the main and sub-spindle, allowing for machining on both ends of the workpiece. Live tooling can rotate and move the cutting tool in the other three axes, allowing for more intricate cuts.

Manufacturing Uses for 4-Axis Machines

-Cutting features on cylindrical or curved pieces

-Working along the side of the material without manually rotating and re-zeroing the machine

-Continuous cutting

-Making multi-axis rounded features

What is 5-Axis CNC Machining?

5 Axis machining is the term used to describe a machine’s capacity to maneuver a tool or workpiece in five axes concurrently. While the X, Y, and Z axes are utilized in standard machining, the addition of two additional axes, namely the A-axis and B-axis, through the use of a 5-axis CNC machining tool, endows the cutting tools with a multidirectional approach.

There are several types of 5-axis machines, including:

1. CNC milling machines: capable of simultaneously milling and drilling complex parts along five axes.

2. CNC routers: Like CNC milling machines, routers use rotating cutting tools to carve out complex shapes from various materials.

3. CNC lathes: use cutting tools to remove material from a rotating workpiece, allowing for complex turning operations along five axes.

4. Laser cutting machines: use a laser beam to cut and shape materials along five axes precisely.

5. EDM machines: EDM (electrical discharge machining) machines use an electrical discharge to erode materials, allowing for precise cutting and shaping along five axes.

Manufacturing Uses for a 5-Axis Machine

-High-accuracy pieces

-Faster turnarounds

-Making intricate workpieces

-Machining complex geometries and features

-Less operator interaction

Main Difference Between 3, 4, 5 Axis CNC Machining

3-axis, 4-axis, and 5-axis CNC machining differ primarily in the following ways:

Working Principle

A 3-axis CNC machine moves the cutting tools along X-axis, Y-axis, and Z-axis. A 4-axis CNC machine adds a rotational axis (A-axis), and a 5-axis CNC machine adds a tilting axis (B-axis) to the three linear axes, allowing for more complex machining operations and greater flexibility in part design and manufacturing.

Precision & Accuracy

The more axes a CNC machine has, the more accurate and precise it becomes. Typically, a 3-axis CNC machine can reach 0.001-inch precision, and 0.002-inch accuracy, a 4-axis CNC machine can do 0.0005-inch precision and 0.001-inch accuracy, and a 5-axis CNC machine can do 0.0001-inch and 0.0005-inch precision.

Applications

For simple milling and drilling tasks on flat or prismatic pieces, we frequently employed the 3-axis CNC machines, such as flat panels, molds, or basic mechanical elements. They are perfect for making simple workpieces with simple geometries.

More complicated items with curved or cylindrical characteristics work best on 4-axis CNC machines. They are used to machine components, like gears, impellers, or camshafts, that require different rotating movements.

Manufacturing extremely sophisticated items with intricate geometries, such as aircraft components, medical implants, or automotive parts, requires the usage of 5-axis CNC machines. They are perfect for objects that need simultaneous machining operations from several angles or intricate features that are difficult to accomplish with 3- or 4-axis machines.

Costs

CNC machining costs depend on complexity, materials, automation level, precision, tooling, and volume. 5-axis machines are the most expensive, and 3-axis machines are the least expensive. However, costs vary based on quality requirements, factory capabilities, and other factors. A careful evaluation of production requirements can determine the most cost-effective solution.

Lead Time

The production lead time for machining parts on a 3-axis machine is faster than on a 4-axis or 5-axis machine. A 3-axis machine can typically produce a part in a few hours to a day or two. A 4-axis machine can take a bit longer, ranging from a few hours to a couple of days, while a 5-axis machine can take several days to produce a complex part. However, actual production lead times can vary widely depending on various factors.

Here below is a chart for a quick check of different axes CNC Machining

5-Axis Machining vs. 3+2 Axis Machining

5-axis machining uses three linear axes and two rotational axes to machine complex geometries simultaneously. The 3+2-axis machining process combines a 3-axis manufacturing process with two additional axes for rotating the holding tool in a fixed position rather than manipulating it repeatedly during the machining process.

5-axis machines offer the advantage of achieving complex geometries with greater precision, thanks to the ability to work with tighter tolerances. Meanwhile, a 3+2 system allows for improved access to features by holding less complex parts in positions that are better suited for the task.

Benefits of 5-axis Machining

5-axis machining aids in the cost-effective production of complex designs. The following are some of the benefits of switching to 5-axis machining:

Minimized Setup

A 5-axis machine can create mechanical components on almost all surfaces, except for the clamping area and bottom. On the other hand, a 3-axis machine needs multiple setups and manual rotation to work on contoured parts or parts that require machining on different faces. With 5-axis technology, the whole job can be done in one setup, which saves time and reduces the number of setups needed.

Complex Designs

With 5-axis machining, it’s possible to create complex shapes and designs using a wider range of angles and curves than with traditional machining methods. In the past, achieving such intricate designs required multiple setups and specialized fixtures. But now, 5-axis machining eliminates the need for complicated fixtures because the workpiece can be securely held in place and rotated to achieve the desired shape all in one process.

Rotational Accuracy

When a workpiece is removed from a machine, it can lose its precise alignment, which is essential for producing high-quality results. However, 5-axis machining is more accurate than 3-axis machining because it allows for the entire job to be completed in one setup. This means that complex shapes can be created without sacrificing accuracy or quality control.

Faster Material Removal

In 5-axis machining, the cutting tool stays in contact with the cutting surface, which makes the process faster and less expensive because it can remove more material with each pass.

Better Surface Finishes

The fourth and fifth axes on a machine tool make it easier to position the workpiece and cutting tool, which allows for the use of shorter cutting tools. This reduces vibrations during cutting and improves the surface finish. Additionally, using a 5-axis machine tool can save time because it can perform multiple operations on a single part without needing to reposition it. In contrast, a 3-axis machine tool requires more cutting to achieve a good surface finish, which takes more time.

3 Axis vs. 4 Axis vs. 5 Axis Machining, Which Is Better?

The best machining option between the 3-axis, 4-axis, and 5-axis depends on the specific requirements of the parts being produced and the machinist’s available resources and expertise. For simple parts, 3-axis machining is typically sufficient and cost-effective. 4-axis machining is a better option for parts with more complex shapes as it can rotate the part around an additional axis. For extremely complex parts requiring machining from multiple angles, 5-axis machining is the best option. However, the increased number of axes also means higher programming, operation, and equipment cost complexity. Therefore, carefully evaluating costs and benefits is necessary to choose the optimal option.

Conclusion

3-axis machining is the primary option for simple parts and low-volume production runs. 4-axis machining adds a rotary axis, allowing access to features from multiple angles, making it useful for medium-volume production runs. 5-axis machining adds a tilt axis, allowing for even more complex parts to be machined with high precision, suitable for high-volume production runs or pieces requiring high precision.

With the development of technology, even the 6-axis CNC machines have been invented with three linear axes (X, Y, Z) and three rotational A, B, and C axes to achieve greater accuracy.

Ultimately, deciding which option to use will depend on the CNC machined parts’ complexity, the required accuracy, the target price, and the production volume.