Computerized Numerical Control (CNC) is an automated process where the movement of production equipment is controlled by pre-programmed software and code. These high-tech machines are primarily used for turning raw materials into precise parts at accurate specifications.
Within the overall spectrum of this technology, there are two major techniques in common rotation – CNC Milling and CNC Turning. When compared to manual techniques, both offer superior accuracy and time efficiency.
If you are about to engage with an engineering or manufacturing company for CNC purposes, we are here to break down each style and give you the lowdown on where, when, and why to opt for milling or turning.
CAD-CAM Technology
Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM) are the collective backbones of CNC cutting tools and technology. Designed to work hand-in-hand, these intuitive pieces of software form the first part of the overall process. The primary purpose of this software is to create the designs, manufacturing prototypes, finished products, and production runs. This information is then used to initiate the final stage of cutting and refining.
CNC Milling – How It Works
The foremost advantage offered by the CNC milling machine is the ability to progressively remove material from the original piece to produce a customized part/product. Of course, this process is automated and utilizes multi-point cutting tools to achieve a precise and accurate result. Regardless of the automated element, milling machines need to be operated by trained professionals in line with the necessary safety precautions.
When to Apply
A CNC Milling machine can be applied to a wide range of materials, including everything from plastic to metal, glass, and wood. Areas that fall under the CNC milling spectrum generally involve mechanical, electrical, thermal, and chemical processes. CNC milling delivers exceptional results for rigid, rectangular, and square shapes without a rounded geometric structure.
The four primary forms of CNC milling include
- Face milling
- Plain milling
- Angular milling
- Form filling
CNC Turning – How it Works
Used to create rounded, conical, and cylinder parts, CNC turning machines are slightly less versatile than CNC milling yet remain highly effective in certain instances. You may commonly hear these machines referred to as CNC lathes or turning centers. A turning center can either be horizontal or vertical.
Machines of this style work through a cutting tool that is attached to a turret. This tool is then activated by automated computer technology to move in the direction of a spinning workpiece.
When to Apply
The CNC turning technology is capable of handling thousands of single parts at a time. Effectively, this means that lathe-based turning or boring can be very cost-effective. For complex spherical and rounded parts, a twin-spindle lathe machine is often the best method.
Turning technology produces shapes with both an Outer Diameter (OD) and an Inner Diameter (ID). Therefore, the machines are ideal for parts with symmetry around the axis and can be easily clamped in the spindle.
Key Differences
As we have established, both CNC Milling and CNC Turning are essentially used to achieve the same overriding goal. However, the fundamental difference between milling and turning surrounds the connection between the cutting device and the material. While a turning machine will force the workpiece to rotate, the milling machine creates the opposite effect – the cutting tool forces the piece to rotate.
The second major distinction lies in the use of a lathe. The lathe is a critical component of various forms of CNC turning machines. Mills, on the other hand, doesn’t use this technology. This primarily enables them to create a wide range of different shapes. For round shapes, however, CNC turning technology is typically in a class of its own. Achieving the perfect level of roundness can be more difficult on a CNC milling machine.
CNC Milling Advantages
Whether you are a manufacturer, sole trader, or prototype business, mills offer a versatile service for the creation of varied shapes. While a CNC milling machine is inherently useful for the transformation of raw materials, it can also be used for roughing, end-milling and post-machining.
Milling is a premium alternative for square and rectangular items. In addition, this technology is also quick, repeatable, and affordable when produced in low volumes. These features have firmly established CNC milling as a leading choice for rapid prototyping requirements.
Milling Part Examples
So, what specific products are created from CNC milling? Let’s delve into a list of the common types.
- Metals
- Gears
- Engine parts
- Plastics
- Ceramics
- Water Pumps
CNC Turning Advantages
CNC turning technology excels in three core areas, accuracy, speed, and geometric definition. In terms of accuracy, the precise computerized turning center is ideal for boring holes that meet intricate dimensions tolerances. Although it can produce parts at an incredible accuracy, each machine operates at equally remarkable speeds and efficiency. Quicker assembly, therefore, can lower overall production costs.
Lastly, CNC turning technology is renowned for its ability to refine materials down to smooth circular shapes and spheres. Products with rounded profiles, therefore, are naturally created with turning center machinery.
Turning Part Examples
While CNC turning can be used to produce a wide variety of parts, some of the most common include:
- Rollers
- Car parts
- Firearms
- Turbines
- Shafts
- Nozzles
The Multi-Pronged Approach
In certain instances, an engineering firm may carry out both CNC milling and turning. This process will generally center on the use of turning, followed by a final refinement with the milling machine. Of course, this can only occur if the operator has access to both in the same facility. This may be worth enquiring about before you send the order off to the manufacturer.
Seek Out Advice from the Experts
If you want further clarification, advice, or recommendations, your best bet is to reach out to a specialist CNC provider. Their staff/machinery operators should be able to advise you as to whether your product is most suited to CNC milling, turning, or a combination of both.