CNC turning is a machining process where a cutting tool is used to remove material from a rotating workpiece. This can be done either by feeding the cutting tool into the workpiece (turning), or by moving the workpiece past the cutting tool (facing). CNC turning can be performed on both ferrous and non-ferrous metals, as well as plastics and composites. The most common type of CNC turning machine is the lathe, which is typically used for cylindrical parts.
However, there are also specialized machines for turning spherical and irregularly-shaped parts. CNC turning can be done either manually or with the help of computer numerical control (CNC) technology. When using CNC turning, the cutting tool is mounted on a spindle that is driven by a motor. The workpiece is mounted on a chuck or collet and is rotated at high speeds. The cutting tool is then fed into the workpiece, removing material as it goes.
The speed at which the cutting tool is fed into the workpiece (known as the feed rate) and the speed at which the workpiece is rotated (known as the spindle speed) can be controlled to produce a variety of different finishes on the part. For example, a high feed rate and low spindle speed will result in a coarse finish, while a low feed rate and high spindle speed will result in a fine finish.CNC turning can be used to produce parts with a variety of different shapes and sizes. The most common shapes that are produced using CNC turning are cylinders, cones, and disks. However, more complex shapes such as spheres, helices, and threads can also be produced. CNC turning offers a number of advantages over other machining processes. It is capable of producing parts with very tight tolerances and intricate details that would be difficult to produce using other methods. In addition, CNC turning is a relatively fast process, which makes it ideal for producing large quantities of parts.
The most common types of turning
-Conventional turning, also called horizontal turning, is the most common type of turning. In conventional turning, the workpiece is mounted on a spindle that is rotated by a motor. The cutting tool is held in a chuck or collet and is fed into the workpiece to create the desired shape.
-CNC turning, or computer numerical controlled turning, is a type of machining that uses computerized controls to operate the machine tools. CNC machines can be programmed to perform very precise operations, making them ideal for complex shapes or large production runs.
-Swiss-type turning, also called slide-rest turning, is a type of machining that uses a slender, rotating workpiece. The cutting tool is fed into the workpiece from the side, rather than from the top or bottom. Swiss-type turning is often used for small parts that require high precision.
-Live tooling turning is a type of CNC turning in which the spindle of the machine tool is equipped with tools that can be used to perform drilling, tapping, or other operations while the spindle is still spinning. This allows for complex shapes to be machined in a single operation.
-Discrete part manufacturing (DPM) is a type of machining that produces parts one at a time, rather than in batches. DPM is often used for prototype or low-volume production runs.
CNC turning problems and their solutions
CNC turning can be problematic at times, especially when trying to achieve tight tolerances. The following are some common problems that can occur, along with their solutions:
1. Chatter
Chatter is a vibration that can occur when cutting, and it can cause the finished product to be uneven or have a poor surface finish. It can be caused by a number of factors, such as dull tooling, incorrect tooling setup, or high spindle speeds. To solve this problem, first, check that the tooling is sharp and properly set up. If everything looks good there, try reducing the spindle speed.
2. Tool Breakage
This is another common problem that can occur when machining with CNC turning. It can be caused by a number of factors, such as using excessive force, incorrect tooling setup, or high cutting speeds. To solve this problem, first, check that the tooling is properly set up and that you are not applying too much force. If everything looks good there, try reducing the cutting speed.
3. Poor Surface Finish
This is usually caused by using dull tooling or incorrect tooling setup. To solve this problem, first, check that the tooling is sharp and properly set up. If everything looks good there, try increasing the spindle speed.
4. Incorrect Tolerances
This can be caused by many factors, such as cutter throw-out (when the cutting tool is not perpendicular to the workpiece), incorrect tooling setup, or human error. To solve this problem, first, check that the tooling is properly set up and that the cutter is perpendicular to the workpiece. If everything looks good there, try measuring the tolerances again to double-check for accuracy.
5. Scrap Rate Increase
This can be caused by a number of factors, such as using incorrect tooling, incorrect CNC program, or human error. To solve this problem, first, check that the tooling is correct and that the CNC program is correct. If everything looks good there, try increasing the tolerance level to give yourself some room for error.
The above are just some of the common problems that can occur when CNC turns. By being aware of these problems and their solutions, you can help to ensure that your machining process is as smooth and efficient as possible.
Conclusion
CNC turning is a popular machining process used to create cylindrical parts. In CNC turning, a cutting tool is mounted on a spindle and fed into a rotating workpiece to remove material and create the desired shape.CNC turning can be used to produce parts with complex shapes and geometries, and it offers several advantages over traditional machining methods such as greater accuracy, repeatability, and productivity.