October 29, 2024
CNC machining is a process to machine precision parts. Most people will refer to any type of CNC operation as simply CNC machining. But, not all CNC processes and machines are the same. There are quite a few different types of CNC machines that are used for various operations.
Two broader categories of CNC machining is CNC Milling and CNC Turning.
These processes have similarities, but they’re not the same. If you’re planning a project, it’s important to understand which type of machine is best for you parts and design. Our team helps you decide how to machine your parts in the most efficient way, but you can read this post to learn more about the differences.
The biggest difference is how the material is cut away to form the part.
CNC milling rotates the cutting tool, while CNC turning rotates the part against a fixed cutting tool. Both machines take a bar of raw metal and removes material to form the part based on the design specifications.
These two machining processes are used for different types of parts. CNC turning is commonly used to form cylindrical and symmetrical parts and shafts. CNC milling is used for complex parts with square edges or multiple angles. Both machining processes can produce high quantities of precision parts efficiently.
CNC milling and turning are used for various industries, including:
When cutting the material, CNC turning uses a single point cutting tool that is in continuous contact with the raw material. CNC milling uses multi-point cutting tools that make multiple cuts on the material. The difference makes turning more efficient for cylinder shaped parts, and milling is better for irregular shaped parts, or parts with multiple surface features.
CNC turning is used for many different parts in various industries. Because the part is spinning during the machining process, nearly all of the parts that are CNC turned are symmetrical, like precision rods, spacers, or shafts. You could also turn a part like a chess pawn like this video show, but a chess knight would be better to mill because they’re not symmetrical.
Precision CNC turning uses a lathe that holds a round bar stock that rotates at very high speeds. The rotation speed depends on the material being machined. Most CNC turning lathes can reach ±0.002″ tolerances, which is similar to milling.
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CNC milling is primarily used to machine more complex parts, square parts, and asymmetrical parts.
Because CNC milling moves the cutting tool, machining can be performed on multiple axis. The standard milling machine moves the cutting tool on 3 axis: X, Y, and Z. These three axis can design most parts, but there are also 5-axis machines that move diagonally and at an angle.
A 5-axis machine is able to produce just about any part that can be CNC machined. These machines are more expensive and require more experience to set up. Once they’re set up, it can machine more parts faster than a 3-axis machine.
The CNC mill is sometimes used for finishing machining, such as adding a hole, angle, slot, or threading to a semi-finished part. Other parts can be milled from raw material to finished part.
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When choosing between CNC turning and milling, it’s essential to consider the material and design factors that can influence the choices.
Certain materials may be more suitable for one process over the other, depending on their machinability and characteristics.
For example, softer materials like aluminum, brass, and plastic are generally easier to machine using both turning and milling processes. However, harder materials like stainless steel or titanium may require specific tooling or cutting parameters to achieve the desired results. In such cases, it’s crucial to consider the capabilities of the equipment and the experience of the machinists.
The complexity of the design plays a significant role in determining the choice between CNC turning and milling.
As we mentioned, turning is more suitable for parts with rotational symmetry, such as shafts, rods, and bushings. While CNC milling is better suited for creating intricate shapes, flat surfaces, and features like pockets or slots that require more detailed cutting operations.
The level of precision required can also impact the choice between turning and milling. While both processes can achieve high levels of accuracy, milling may be better suited for projects that require extremely tight tolerances or complex geometries that are difficult to achieve using turning alone.
Another type of CNC machine is a hybrid machine that combine both CNC turning and milling capabilities. These machines, often referred to as mill-turn centers or multitasking machines, allow manufacturers to perform both processes on a single machine.
Hybrid machines have become increasingly popular in the manufacturing industry, as they offer a range of benefits, including reduced setup time, improved production efficiency, and enhanced precision. By integrating both CNC turning and milling capabilities, these machines provide an efficient solution for the production of complex parts that require multiple machining operations.
If you have more questions about CNC milling and CNC turning, don’t hesitate to reach out to our team.
We have worked on thousands of custom projects in a range of industries. We are happy to help you pick the best machining process for your next project and give you a customized quote for your project.