CNC Turning Process – Detailed Explanation

When you learn about modern manufacturing, you’ll find automatic manufacturing the most important part of it. Consecutively, the CNC turning process is the most crucial method of modern automatic manufacturing. You know CNC stands for Computer Numeric Control. It involves the use of computer programs. That means once you insert the code in the machine, it automatically creates hundreds and thousands of metal parts. Indeed, automatic manufacturing is incredibly fast.

Since the CNC turning process is crucial to modern manufacturing, understanding its fundamentals is also crucial. Learning its basics lets you distinguish different types of products made from distinct turning processes. Overall, it helps you choose the right type of metal parts for your projects.

The CNC turning process is a material shaping method. In the turning process, you can mostly create cylindrical parts. As the name implies, this turning process typically comes with CNC technology. The process rotates a cylindrical workpiece. On the other hand, it traverses a cutting tool along the length of the workpiece.

These two operations continuously remove material and create the desired shape. Normally, the cutting tool is controlled by a CNC system. You know, it can move along multiple axes with high precision and accuracy.

One of the key advantages of the process is its ability to create complex metal parts. You can literally obtain tolerances up to 0.01mm. It also provides excellent surface finishes. You may often find various CNC turning parts in the automotive, aerospace, medical, and electronics industries. Products like shafts, bushings, pulleys, and fittings are noteworthy.

Turning Process is a type of subtractive manufacturing process. It means this process creates metal parts by removing materials from the workpieces. Before understanding its working principle, it is necessary to know more about a CNC turning machine structure.

Usually, a CNC turning machine comes with a machining section and a controller section. In the machining section, you may find a bed, headstock, tailstock, carriage, spindle, and tool turret. On the other hand, the controller section comes with a display only. You can either write CNC codes on it or insert the pre-programmed file.

The working principle of a CNC turning machine is simple. The spindle on the machine holds the workpiece. In addition, the tool turret holds various types of cutting tools. You can calibrate the position of the tool turret using adjustment screws. Once you start the machine, the spindle starts rotating at a certain speed. The tool turret follows the CNC codes. The whole process works together to make certain shapes on the workpiece.

When you explore turning more, you will find distinct types of operations. This diversity typically arises from the various uses of cutting tools. In addition, the necessity of different shapes, features, and surface finishes also differentiates the types of operations. Usually, manufacturers and engineers determine the types of operations. In most cases, you may find the following ten types of CNC turning operations in modern manufacturing.

Type #1 Turning

The CNC turning method removes material from the outer diameter of a workpiece. Using this method, you can create cylindrical shapes of metal parts. It’s the most common method for shaping, sizing, and finishing shafts, pins, and sleeves.

Type #2 Hard Turning

This CNC turning method is almost like the usual turning method. They differ by using robust cutting tools and techniques to achieve higher precision results. You may not need any additional grinding methods for hardened workpieces.

Type #3 Facing

CNC facing is the process of removing material from the end face of the workpiece. You can create a smooth and flat surface. It’s often used to ensure perpendicularity and parallelism between faces. It prepares the workpiece for subsequent operation.

Type #4 Grooving

This CNC turning method allows you to cut narrow channels or grooves into the surface of a workpiece. These grooves serve some particular purposes. It helps in accommodating O-rings and retaining rings. It also provides clearance for other components in assemblies.

Type #5 Parting

CNC Parting is also known as CNC cutoff. You can separate a workpiece from the primary workpiece using this method. Note that this process is named after a specialized cutting tool called the parting tool.

Type #6 Threading

This CNC turning method is also one of the most popular in modern manufacturing. Using this method, you can make spiral grooves into the surface of a cylindrical workpiece. You know you create both internal and external threads.

Type #7 Knurling

CNC knurling makes patterns of straight or diamond-shaped engravings on material surfaces. By doing so, you can technically increase the grip and aesthetics of the metal part.

Type #8 Boring

CNC boring enlarges existing holes or internal features in a workpiece. You can also create new holes using this method. But you should know that this type is included in turning processes. The workpiece rotates at a certain speed, and the cutting tool creates the holes.

Type #9 Chamfering

Chamfering is another type of CNC turning process. Using this method, you can create beveled edges or angles onto the corners or edges of a workpiece. You know why chamfering is necessary for every metal part. It reduces the risk of damage or injury from sharp edges.

Type #10 Reaming

Finally, you can enlarge or refine existing drilled holes in a workpiece using the reaming method. What makes reaming and boring different is that boring can create new holes, but reaming can not.

In the CNC turning process, the number of axes is generally the direction the cutting tool can move relative to the workpiece. You know, a typical CNC lathe operates with three axes: X, Y, and Z. These axes control the tool torrent’s movement along the workpiece’s diameter, length and depth.
Modern turning machines may have multiple axes as per different requirements. You can add extra axes, such as a fourth axis for rotational movement or even six axes for more complex operations.
These extra axes enable intricate machining tasks. For example, it allows cutting features at various angles or creating complex contours. Note that it enhances the machine’s versatility and precision in manufacturing processes.

Number of AxesName of Axes
3 Axes CNC TurningX, Y, Z
4 Axes CNC TurningX, Y, Z, A
5 Axes CNC TurningX, Y, Z, A, B
6 Axes CNC TurningX, Y, Z, A, B, C

In modern manufacturing, both CNC turning and CNC milling are popular. You can find a wide range of products produced through these two machining processes. However, they have some fundamental differences. Let’s check them out.

AspectCNC TurningCNC Milling
OperationRotating workpiece against a stationary toolStationary workpiece with a rotating cutting tool
ToolingSingle-point cutting toolMulti-point cutting tools
Workpiece ComplexityLimited to rotational symmetrySuitable for complex 3D shapes and features
Surface finishGenerally smoother surface finishIt may require additional finishing operations
Material Removal RateFasterFaster
Setup TimeGenerally, quicker setup timeLonger setup time due to fixture and tool setup
ApplicationIdeal for cylindrical parts and shaftsIdeal for complex parts with intricate details

You may already know that multiple CNC machining methods exist to create similar metal parts. But how do you choose the correct method? Therefore, assessing whether CNC turning is the optimal method is essential. When you do that, several factors come into play.

1: Part Geometry

CNC turning is typically for producing cylindrical or rotational parts. You may require additional operations for complex geometries.

2: Material

With various metals. Popular materials are aluminum, steel, brass, and titanium. In this case, you can consider the material’s hardness, machineability, and other properties.

3: Tolerance & Surface Finish

CNC turning can achieve tight tolerances and smooth surface finishes. You can technically achieve 0.01mm of tolerances.

4: Design Considerations

5: Symmetry

Parts with symmetrical features around a central axis are suitable for CNC turning. These types of metal part designs provide the most efficient machining.

6: Tools Access

Ensure the design allows for proper tool access and clearance. You must double-check, especially for those with interior features or complex shapes.

7: Const & Times

Finally, evaluate the cost-effectiveness and production time. You can compare alternative methods like CNC milling, drilling, or grinding. You can also consider setup, tooling, and machining time.

Returning Questions

Q1. Why Is CNC Turning Important?

CNC Turning is important because it provides excellent precision, efficiency, and versatility. You can create almost all types of cylindrical components. In addition, it offers high-volume production and maintains tight tolerances (0.01mm).

Q2. How Many Axes Can A CNC Machine Have?

A CNC turning machine can have up to six axes. Although, in CNC milling operations you can add axes up to 12 directions. It depends on how complex your metal parts are.

Q3. What Materials Are Used in CNC Turning?

The CNC Turning method is a versatile machining solution. It means you can work with a wide range of materials. Popular turning materials include aluminum, steel, brass, and titanium. In some situations, you can also work with plastics and composite materials.


Let’s wrap everything up! CNC turning is a vital process in modern manufacturing. It offers various operations like turning, threading, facing and more. With different axes configurations, it can meet your diverse machining needs.
When you compare CNC turning with CNC milling, understanding material suitability and design considerations is crucial. You know, CNC turning plays a crucial role in precision metal part fabrication.

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