A CNC milling machine is a machine tool used to machine parts by removing chips (waste material) with a multi-tooth cutting tool known as a milling cutter. The cutter is mounted in a rotating spindle head, while the workpiece is clamped to a table or main carriage. These machines can move along three axes: up and down, left and right, and forwards and backwards.
Put this way, however, the definition could just as well apply to conventional, manually operated milling machines. What sets CNC milling machines apart is their electromechanical operation: their operations are executed by a computer that controls the various cutting parameters. CNC stands for “Computer Numerical Control”, the system these machines use.
Key points about CNC milling machines
To find out whether a CNC milling machine could be useful to you, you need to consider several factors relating to its specifications, how it works and what it can do.
CNC vs. conventional milling machines
One particular feature of these machines is that, unlike conventional milling machines, the head carrying the cutter is not always fixed; it can move around the workpiece to make the required cuts more easily and with greater versatility.
In fact, some types of CNC milling machine do not even have a main carriage to move the workpiece, which stays in a fixed position. This may be the case with machines designed mainly for working wood, plastic or glass.
Different CNC milling machine models
Other models have both a moving carriage and a moving head, controlled by the computer numerical control. It is worth pointing out that some conventional milling machines can be converted to CNC by installing kits designed specifically for this purpose. After all, most CNC milling machines use the same moving parts as conventional ones.
Broadly speaking, there are fully computerised CNC milling machines, semi-automatic CNC milling machines and retrofitted CNC milling machines (converted conventional models).
Whatever the model, the workpiece material can be roughed from any side required, with far greater precision, speed and efficiency than on conventional milling machines.
Applications of a CNC milling machine
The applications of this machine tool range from small art studios and digital design and fabrication companies to mass production in large factories. That is why CNC milling machines vary not only in type and model, but also in size and production capacity.
For the same reason, there are also many types and sizes of milling cutter. There are cutters designed for holes, slots, edges, flat faces, gear teeth and much more. The main focus is on milling metals such as aluminium, but they are also very useful for working wood or PVC.
CNC milling machine vs. lathe
This machine tool differs from a lathe in several ways, but the most distinctive is that its cutting tool (the milling cutter) has several cutting edges, whereas a lathe tool has a single cutting edge. That is precisely why it is regarded as a milling tool rather than a single-point cutting tool.
When does it make sense to have a CNC milling machine?
CNC milling machines can complete more complex tasks than conventional machines, above all because they allow movements to be programmed that could not otherwise be achieved with manually operated levers and handwheels. Here are some of the reasons why it is worth having one of these modern machines:
- Essential for complex shapes: a CNC milling machine may be right for you if you need to produce diagonal lines, circles or complex three-dimensional shapes.
- Better design quality: some CNC milling machine models feature a screen with CAD (computer-aided design) software, allowing highly detailed designs to be created directly on the machine and then produced with greater precision.
- Consistency in series production: whatever milling you need for the series production of a given product, CNC versions ensure greater consistency between the units produced.
- More efficient productivity: a CNC milling machine completes jobs faster, which means greater production capacity and even better use of materials.
Finally, bear in mind that there are countless models available, which makes it hard to define clearly identifiable types. Each manufacturer develops different models to meet every possible milling need. In this respect, it should be made clear that not every CNC milling machine will be useful to you, so it is advisable to research carefully to find the most suitable model for each case.