CNC MACHINES: what they are and how they work
Are you passionate about the world of CNC machines or do you want to buy one but are you lost in the technologies and models?
In this article we try to do some clarity about what CNC machines are and how they work.
WHAT CNC MACHINES ARE
CNC machines are machine tools whose movements are controlled by an electronic device integrated in the machine called “numerical control”. The movements and functions of these machines are pre-established, they are pre-set to a table through specific software.
These characteristics make them excellent for performing high precision machining that require long processing times, but they prevent the machine from interacting with the external environment autonomously in the event of collisions or unforeseen events. For this reason they must be controlled by an operator, who has the task of setting up the program, preparing the blanks to be processed and intervening in case of problems or corrections in processing.
It seems complex, isn’t it? But once you understand the mechanism, your workflow will improve and you will be able to increase your production capacity, and especially your income.
So, what are these machine tools for?
In other words, these machines are mainly used to export material and create objects of any kind, from the design table to high precision mechanical components.
Then we start from a block of raw material, and through a tool, such as a cutter, we remove material until the finished object is obtained.
These machines are very widespread in industrial processing due to their ability to work many materials such as:
- EPS and XPS polystyrene,
- soft metals,
- much else
Basically, you can work all the materials. Just find the machine with the most suitable technology.
But let’s get to the bottom of this vast world, let’s try to understand better what these CNC machines are.
WHAT "CNC" MEANS
You will surely have asked yourself what CNC means, the acronym stands for “Computer Numerical Control” and means that an internal electronic device, is responsible for controlling the movements and functions of the machine during processing, all this depending on a well defined work program.
Be careful not to confuse the CNC with the robots, the latter have a different technology, and are able to adapt to changes in the environment and sudden obstacles.
Now let’s try to understand how the machine tools do these movements correctly.
The numbers generated are converted into a 3-dimensional XYZ coordinates chart that are sent to the machine, thanks to these the machine can understand where position itself exactly, moving its axes with precise movements and replicating the design or the path imported.
CLASSIC AND INNOVATIVE CNC MACHINES
As we have already mentioned, the panorama of CNC machines is enormously vast, there are different technologies depending on the processing or the material you want to work with.
Click here to see all our CNC machines.
Here we will show you only the most classic applications of numerical control technology:
CNC drilling machines,
The CNC lathe,
CNC milling machines.
These three types of machines exploit numerical control technology and apply it to different processing principles.
The CNC drilling machine takes care of drilling a material through the rotation of a drill bit, which comes into contact with a static block and pierces it.
The CNC lathe uses the opposite principle compared to the drilling machine, the material to be machined is rotated against the tool, which remains fixed
The CNC milling machine is the most common numerical control machine and is used on an industrial and artisan level.
The drills shape the material, by rotating the tool at high revolutions, remove the stuff in excess.
Milling machines are able to make engravings, sculptures, works of art and high-precision workmanship. The best CNC machines come to a precision of one ten thousandth millimeter (100 nanometers).
If you want to buy one, look at our CNC milling machines for precision crafts and milling.
In addition to these 3 classic applications, numerical control is applied to many other types of machines with different technologies and uses.
Among the applications with the most common alternative technologies are:
CNC laser cutting,
CNC plasma cutting,
Water jet machines,
Hot wire cutting machines,
THE AXES OF NUMERICAL CONTROL MACHINES
The main feature of CNC machines is the degrees of freedom, which represent the number of moving axles of the machine. A few paragraphs further up we mentioned something about the axes, but we need to go deeper into this topic. What do the axes do and how many can a machine have?
The axes allow the tool to be inclined related to the work plane and, depending on the number of degrees of freedom, give a greater or lesser flexibility of movement during processing. Below I report the substantial characteristics of each machine according to the axes it carries:
The 2-axis CNC machines allow movements only on X and Y, and the machining will not have any variation in depth.
The 2.5 axes CNC machines allow to work in 3 dimensions, but they are limited to an interpolation only on the X and Y axes. The Z axis generally has a partial movement and can vary its altitude, but it can’t be interpolated with the two others.
CNC machines with 3 axes allow you to work simultaneously in height, width and depth, they are excellent for working on free-form surfaces. This category usually includes CNC milling machines.
The 4-axis CNC machines add the rotation movement applied to the tool or to the workpiece. In the 4-axis interpolated machines the rotation movement occurs simultaneously with the other 3 axes, while in the 4-axis indexed machines the rotation can take place only when the other three axes are stopped.
The 5-axis machines combine both the tool holder head and workpiece rotation to the other 3 axes. These machines have excellent movement flexibility and allow interpolation simultaneously.
SOFTWARE TO COMBINE WITH CNC MACHINES
The universe of numerical control machines is not only composed of machinery, technologies and mechanical components, but also of software components, namely: CAM software and CAD software.
Computer Aided Design (CAD) software are programs that are used to perform technical drawings directly on computers.
These software have gradually replaced the manual design and allow the generation of the project to be carried out by the CNC machine.
If you want to start creating projects at CAM, you’ll want to start with the entry level CAM software suite we offer:
CAM (Computer Aided Manufacturing) software, on the other hand, are programs that convert CAD drawings into toolpaths, i.e. instructions that can be interpreted by the machine controller. These software convert drawings made by CAD into numbers, which are considered by the machine as coordinates of a chart. The coordinates are translated by the CNC machine into real movements and allow the tool movement and the material modeling.
To sum up, first create a 2D / 3D drawing or drawing of the object (CAD) on the computer, then import the file generated in the CAM program, which will be able to translate and define the movements to be performed by the axes and from the tool.
Also available on the market are CAD/CAM software, which combine the functions of technical drawing with the programming of toolpaths in a single program.