2 March 2024

numerical control (CN) It is an automation system that allows the movement and position of a machine tool to be controlled through a computer software program. Its importance in the industry is of great impact, mainly because it reduces production costs. Learn more about numerical controlall its features and how this highly efficient number system works.

## What does this machine tool control system consist of?

Numerical control consists of a form of automation in which the processing equipment is controlled through numbers, letters, and other symbols or programmable characters. This happens thanks to a computer program, which offers instructions for the movement and position of the machine tool.

These programs feed the machine via magnetic tape, punched cards, and other media. However, there are differences between these machines and Computerized Numerical Control (CNC) machines, which are fed by computer software such as CAD/CAM.

Commonly used character

The DIN 66024 and 66025 standard establish a series of characters that standardizes the programming language and the interface for the numerical control operation. The most commonly used are the following:

• N: block or sequence number.
• G: preparatory or modal function.
• M: auxiliary or modeless function.
• F: forward speed.
• S: spindle speed.
• T: tool selection.
• X, Y, Z: linear coordinates on the principal axes.
• I, J, K: incremental coordinates on the principal axes.
• A, B, C: Angular coordinates in the secondary or rotary axes.
• D: angle of rotation in a circular interpolation.
• H: tool length compensation.
• R: The radius or height of the arc in a circular interpolation.

Operating principle

The operation of this system bases its execution through a computer or a specific unit integrated into the machine tool. This sends signals to the servomotors that control the coordinate axes of the machine.

This system receive information from sensors that capture the status and operation of the machine tool. It then adjusts the machining parameters according to the conditions.

This mechanical process can be adapted to different types of machine tools, such as lathes, milling machines, machining centers, etc.

numerical control system

It is the device that store and run the program computer containing instructions for the movement and position of the machine tool. This system can be a computer or a specific unit built into the machine tool.

Computer program

Is he numeric data set and alphanumeric that define the coordinates, speeds and trajectories, as well as the machining times of the piece. This program can be created using specific software or using a standardized programming language called G code.

### What kind of machine tools can be controlled with this system?

There are different types of machine tools that can be controlled by numerical control. Depending on the type of machine, the device performs the machining of the part, through different processes: cutting, turning, milling, drilling, among others.

• Court: allows a part to be cut using an abrasive disc, a pressurized water jet, a laser beam or a plasma. This machine has two or more main axes: X and Y axis, and Z axis.
• Turnstile: Allows you to machine cylindrical or conical parts by rotating the part and linearly advancing a cutting tool. This works with two main axes: Z axis and X axis.
• Milling machine: Machines parts with various and precise shapes, such as slots, profiles, cavities, gears, etc. In addition, it can have several axes, depending on the type and complexity of the part to be machined. The main axes are: X axis, Y axis and Z axis.
• Drill: performs the machining of holes in a part by rotating and feeding the drill bit. It operates with a single main axis, the Z axis.

These machines are also grouped in a process of numerical control machining, according to the type of movement they perform. The most common movements:

• punctual movement: These machine tools perform a linear or circular movement in one or two axes. For example, drills or tapping machines.
• Continuous movement: are those that make the same linear or circular movement but in three or more axes, as is the case with lathes or milling machines.
• special moves: These are the machine tools whose movements are more complex or combined in several axes. In this area we can name the machining centers or EDM machines.

## What are the characteristics of the numerical control system?

The characteristics of the numerical control system are very advantageous for the industry engineering. Know what they are:

• Precision: the system machines parts with great dimensional and geometric accuracy. In the process it eliminates human errors and thermal or mechanical variations.
• Speed: Allows you to transform parts with greater speed and efficiency. In addition, it minimizes downtime and tool changes.
• Quality: offers a higher surface and structural quality. At the same time it avoids vibrations that can lead to deformation of the parts.
• Flexibility: the system offers machining of a wide variety of shapes and materials. This is possible thanks to its adaptability to different requirements by modifying the computer program.
• Economy: this system allows to reduce production costs and waste, thanks to the optimization of the use of material and energy.

## What does a numerical control operator do?

This figure is the person who is in charge of carrying out the following tasks during the machining process with the machine tool. Their functions are:

• Prepare the machine tool– You need to check the condition of the machine tool and select and assemble the right tools. It is also in charge of adjusting the machining parameters and placing the part in the clamping device.
• Enter the computer program either through an external storage device, a connection to a network or a keyboard. In addition, you must check that this program is correct and compatible with the machine tool.
• Monitor the process: is responsible for starting and stopping the machining process. You must also observe the operation of the machine tool and the numerical control system. The operator must also intervene in the event of an emergency or anomaly and make the necessary corrections.
• Check the quality of the piece: You must remove the part from the machine tool, clean it and measure it with the appropriate instruments. Then, it makes a comparison with the technical specifications to record the results.

## What type of technology does the numerical control automation system use?

This system uses a series of technologies to be able to carry out its function with successful results. Here we mention the most used.

• sensors: are devices that capture information about the status and operation of the machine tool, such as position, speed, temperature and pressure. The sensors send this information to the numerical control system so that it can adjust parameters of machining.
• actuators: these execute the actions ordered by the numerical control system that refer to movement, rotation and tool change. These devices can be electrical, hydraulic, pneumatic or mechanical.
• interfaces: allow communication between the operator and the numerical control system, through screens, keyboards, mice, joysticks, and others. In addition, they facilitate the introduction and visualization of the computer program and the data of the machining process.
• networks: Whether local or remote, wired or wireless, networks allow the connection between different numerical control system devices. These devices are computers, storage units, sensors, actuators, among others.

## What is numerical control software?

Is the set of computer programs that allow the creation and modification of the computer program that contains the instructions for the machining of the part. Computerized numerical control software or CNC can be of two types:

• CAD software (Computer Aided Design): It is used to design the piece in three dimensions using a geometric model. In addition, it facilitates the definition of the dimensions, shapes and materials of the part.
• CAM Software (Computer Aided Manufacturing): allows the generation of the computer program from the geometric model created with the CAD software. This program also makes it easy to define toolpaths, speeds, times and machining conditions.

## Why is numerical control so efficient in the engineering industry?

There are many aspects that highlight the efficiency of the numerical control system for the engineering industry. Some relevant reasons are:

• offer better accuracyspeed and quality in the manufacture of parts, compared to conventional systems.
• Improves the statistics of cost reduction of production
• It minimizes human errors and offers higher performance.
• They have the ability to adapt to market demands and technological innovations.