CNC turning is a manufacturing process in which bars of material are held in a chuck and rotated while a tool is fed to the piece to remove material to create the desired shape.

1. What is CNC Turning? 

In CNC turning, the cutting tool typically moves in a linear fashion while the work piece rotates. This is different from CNC milling, where the work piece is stationary while the cutting tool moves.

Turning is used to create a variety of shapes, including complex designs and geometries. It’s highly efficient for producing parts that are symmetrical around an axis of rotation. Major examples are as cones, cylinders, or shafts.

2. What are the differences between CNC Turning and CNC Milling?

  • Operation Method:
    • CNC Milling: It involves using a rotating cutting tool that moves along multiple axes to create shapes, holes and etc in the work piece. The work piece is stationary and the cutting tool moves to remove material.
    • CNC Turning: In turning, the work piece rotates on a spindle, and the cutting tool is stationary. The tool is fed into the rotating work piece to remove material and produce the desired the shape.
  • Type of Parts Produced:
    • CNC Milling Parts: Ideal for creating complex shapes and features like slots, holes, grooves, and contours. Milling offers more versatility.
    • CNC Turning Parts: Ideal for creating cylindrical parts such as rods, shafts, and bushings. It is most effective for parts with a round shape.
  • Axis of Motion:
    • Milling Machines: Operate typically on 3 to 5 axes. This multi-axis movement is the key for versatility to be able to produce more complex parts.
    • Turning Centres: Operate on 2 axes (X and Z).
  • Material Removal:
    • Milling: The cutting tool rotates against the work piece, cutting away material as it moves along different axes.
    • Turning: The work piece spins, and the cutting tool moves linearly, parallel or perpendicular to the axis of the work piece.

3.  Which Steel Grades can be CNC Turned?

  • Carbon Steels: Low carbon steels (like 1018) are more ductile and weldable, while high carbon steels (like 1045) are harder and wear-resistant but less ductile.
  • Alloy Steels: These steels are often used for their strength, toughness, wear resistance, and hardness. Examples include 4140 and 4340 steels.
  • Tool Steels: Tool steels are high-carbon steels .They are known for their hardness and resistance to abrasion. Examples are D2, A2, and O1.
  • Stainless Steels: Common grades used in CNC turning include 304 and 316, known for their good formability and corrosion resistance.

4. What are the advantages of CNC Turning?

  • High Precision and Consistency: CNC turning machines can fabricate parts with tight tolerance. Ideal for large production runs where every part needs to be identical.
  • Complex Designs and Geometries: It’s possible to create complex shapes and designs with CNC Turning. This includes intricate cuts, grooves, and curves.
  • Increased Efficiency and Productivity: CNC machines can operate continuously and faster than manual lathes without compromising the precision. This leads to higher production rates and more efficient use of materials and time.
  • Flexibility and Versatility: CNC turning machines can work with a wide range of materials, from various metals to plastics. They can easily switch between different productions specifications, which allows to produce various parts without needing extensive machine reconfiguration.
  • Reduced Labour Costs: As CNC machines are automated, they require fewer operators, reducing labour costs. 
  • Improved Safety: CNC turning doesn’t require manual operation which reduces the risk of accidents in the workplace.
  • Lower Error Rate: The precision of CNC machines significantly reduces the error rate compared to manual turning. 
  • Easy Replication and Scalability: Once a design is programmed into the CNC machine, it can be easily replicated any number of times, which is particularly beneficial for large-scale production runs.
  • Integration with CAD/CAM Software: CNC turning machines can be integrated with computer-aided design (CAD) and computer-aided manufacturing (CAM) software. This allows a seamless transition from design to production.
  • Quick Setup and Changeover: Modern CNC machines have quicker setup times compared to older models and manual lathes, especially when switching between production runs of different parts.

5. CNC Turning Applications

  • Shafts: These are long, cylindrical pieces used to transmit power or motion. 
  • Pins: Precision pins are used in various applications, including as hinge pins, dowels, or locator pins in machinery and equipment.
  • Bushings: These are cylindrical linings designed to reduce friction or provide a protective interface between two parts in mechanical systems.
  • Spacers: Used to create a space between two components in an assembly to ensure proper positioning and alignment.
  • Valves and Valve Components: Essential in controlling the flow of liquids or gases in systems.
  • Pulleys: These parts support movement and change of direction of a belt in machines.
  • Bolts and Screws: Precision threading can be produced with CNC turning.
  • Hydraulic Components: Parts like pistons, cylinders, and connectors, used in hydraulic systems.

Novelty Steel supplies bespoke CNC Turned parts for various applications.

Knowledge Hub