An Overview Introduction to CNC Turning

 

CNC

CNC turning services offer a wide range of technologies for manufacturing cylindrical parts from a variety of materials. Unlike CNC milling, CNC turning rotates the workpiece and introduces a stationary tool into the workpiece. Advanced CNC turning centers go a step further and add milling capabilities to produce highly complex parts.(CLICK HERE) 

CNC Turning Explained

CNC turning is a subtractive manufacturing technique that refers to the process of removing material from a (usually) cylindrical stock, although CNC turning can also be performed on stock shapes such as hexagonal or square bars. The machine rotates the workpiece while the tool moves to engage and remove material until the desired shape is achieved.

Lathes can be either vertical or horizontal. Vertical CNC lathes are often used to machine large and heavy designs because the center of gravity of the material is aligned along the axis of rotation. 

Horizontal CNC turning uses a cantilever effect in the way the workpiece is mounted. A cantilever setup can cause vibrations in large, heavy workpieces, which can affect the quality of the process and cause potential damage to the lathe and tooling. However, vertical turning also has its own disadvantages. One of these disadvantages is chip evacuation: if the chips are not evacuated effectively after cutting, there will be potential problems such as chip re-cutting and part scoring. Therefore, horizontal CNC turning is the most common setup. 

CNC Lathes vs. CNC Turning Centers 

The difference between a CNC lathe and a CNC turning center can be simply described as a function of functionality, with turning centers typically being able to perform a variety of operations, while lathes are simply turning. A lathe is a machine designed to cut a rotating workpiece, while turning is a general term for the process of cutting a rotating workpiece. Prior to CNC technology, lathes were similar and easy to identify. However, as technology advanced, many new capabilities were added to lathes. Therefore, we need to distinguish between simple CNC machines that perform operations like the original lathes, and enhanced machines (CNC turning centers) that can perform turning cutting in more ways. 

Some companies distinguish between the two based on the number of axes of tool paths that the machine can perform. CNC tool paths can be 2D, 3D, 4-axis, or 5-axis (this applies to both milling and turning operations). Lathes are typically 2-axis machines, while turning centers are typically 3-axis, 4-axis, or 5-axis machines. Other companies refer to machines that can perform both turning cutting and milling and drilling operations as turning centers.

 CNC Turning Machine Components 

A lathe consists of a spindle that is connected to the machine’s drive system at one end and a chuck at the other end that holds the workpiece to be cut. The chuck usually has three or four jaws, with three jaws being the most common. Four-jaw chucks can be used to hold square bars and can also be used for eccentric turning. The cutting tools are usually made of carbide inserts. These inserts are mounted on a tool holder that is bolted to the turret using a variety of specialized tool holders, depending on the type of tool. The tool is then indexed as part of the preparation before machining begins. 

Types of CNC Turning Operations 

Facing

Facing is a process used to cut a plane perpendicular to the workpiece’s axis of rotation. The tool is mounted on a tool holder on a lathe. During the process, the facing tool is fed perpendicular to the workpiece’s axis of rotation. Facing can be performed as a roughing operation or a finishing operation. 

Turning

CNC machine turning operations involve removing material from the outside diameter of a workpiece. Turning can be done parallel to the workpiece’s axis of rotation or at an angle to create a tapered workpiece. 

Drilling 

If you need to drill a hole in the workpiece’s rotational axis, you’ll need to use a drill. On more advanced turning centers, you can drill holes in almost any direction, not just the center axis. 

Boring 

After drilling, it may be necessary to enlarge the hole diameter. The simplest way to do this is to perform a boring operation, where a cutting tool is fed into the existing hole and material is removed from the inner wall of the hole. 

Threading 

Threading is the process of cutting threads into a hole or over the outer diameter of a workpiece.

Grooving or Parting 

Grooving is commonly used to create features such as O-ring or circlip grooves, as well as contouring. Grooving tools, sometimes called parting tools, are used to remove the finished part from the workpiece blank. 

Knurling 

Knurling creates a diamond pattern on the outside diameter of a part. This pattern is not created by cutting, but rather the knurling tool compresses the material into the desired pattern. Knurling is most often used to add grippers to a part.

Advantages of CNC Turning 

Advantages of CNC Turning There are many advantages to CNC turning, some of which are listed below:

Accuracy: CNC turning can reliably produce extremely accurate parts, thanks to the automated nature of the system, which eliminates the human factor.

Flexibility: CNC turning is a flexible manufacturing technology that can produce parts of varying complexity. CNC turning centers take this a step further by combining milling and turning capabilities together for maximum flexibility.

Safety: All cutting takes place behind machine guards, meaning the operator never gets close to the rotating material, eliminating the typical risks of manual lathes.

Faster: A CNC lathe can produce parts quickly because it follows a precise set of instructions without pauses, and different tools can be quickly changed when required. 

Sourcing Simplified – Start Your Next  Project With PROTO MFG

Are you looking for a reputable partner for your parts fabrication and machining projects? Look no further. At PROTO MFG, we specialize in CNC machining and related technologies, including sheet metal fabrication, rapid prototyping, etc. Whether it is a project with a simple design or parts with complex geometries, do not hesitate to contact us today!

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