What Is CNC? | System, Working Principle, Types

If you are planning to work in the manufacturing industry, or are a novice in the manufacturing industry, it is normal to feel unfamiliar with the word CNC, because no one will systematically organize all the professional terms in this industry.

Therefore, most people are now prejudiced against the professional term CNC, thinking that CNC means numerical control machining. On the one hand, this is due to the lack of understanding of the meaning of CNC, and on the other hand, it is due to not knowing what CNC stands for.

To help everyone understand what real CNC is, this article will take the following aspects as the starting point to give everyone a clear understanding of CNC.

What Is CNC?

CNC Definition and Background

In simple terms, CNC is the abbreviation of "Computer Numerical Control" in English, and its origin can be traced back to the late 1940s and early 1950s. What we call CNC now is postmodern technology, which is the result of CNC's technical system upgrade after a period of time.

In the beginning, the system composition of CNC was very simple, consisting of hardware circuits. You can understand it as directly issuing operating instructions with wires, without the need for an intermediate transmission system. It is just a direct instruction to make the CNC machine tool respond in a certain way. The CNC of this period is called early CNC, also known as hard NC. In the traditional sense, it is just line integration, which cannot be regarded as a real CNC operating system.

Are CNC and CNC Machining the Same?

What we call CNC now refers to the product of the integration of computer software technology and hardware circuits after the 1970s. This is the integration and innovation of science and technology. If we must investigate what CNC means, according to modern people's understanding, its meaning will change greatly because many people will mislead everyone into thinking that CNC is CNC machining.

CNC≠CNC machining. In my opinion, CNC is just an operating system, and CNC machining is to use this system to perform some specific processing actions on physical materials. The processing object can be metal material or plastic material. The choice of this material is determined by the customer to choose the most suitable material for component processing based on the actual use of the component.

For the CNC machining service we provide, we will let customers provide their own processing materials (customer-supplied materials) for us to perform CNC machining, or choose the manufacturing materials we provide.

The only difference between the two is that the materials provided by the customer will be more accurate, because each country has different standards for the implementation of materials, and there will be some subtle differences in the raw materials produced, but generally speaking, they can achieve the expected product effect.

Through the above description, everyone should understand that CNC and CNC machining are two concepts. CNC refers more to the numerical control system, while CNC machining emphasizes the specific machining part. Whether this link can be coordinated well determines the quality of the parts processed by CNC. The most challenging part of CNC machining is the cooperation between the machining teams.

What Is the Logic of CNC's Operating System and How Does It Work?

The CNC operating system mainly includes three aspects: receiving, translating, and executing CNC programs. Through regular logical processing or reading the program specified by the symbolic instructions, the CNC machine tool performs the specified actions and completes the processing of parts.

In this process, the role played by the CNC system is a real-time multi-tasking computer system, and its main work content process includes the following parts:

1. Receiving CNC programs: The CNC system first receives the CNC program from the input device, which contains the part processing program, control parameters, and compensation data. The processing data of the parts is usually written by experienced CNC programmers.

These data usually exist in the form of NC code, which is automatically generated or manually compiled by CAM software according to the design model of the part. However, each CNC programmer is involved in different fields and has learned different editing software, so the compiled execution program will also be different.

As far as I know, in the current CNC industry, the programmers around me prefer to use Mastercam or UG software to write part processing routes, but no matter which one, the desired CNC part processing effect can be achieved in the end.

2. Translate NC code: The CNC system "translates" the received NC code into machine code that can be recognized by the computer. This process converts human-readable information into a binary form that can be recognized by CNC hardware, i.e. machine code.

This machine code is mainly divided into 2 types (G code and M code) in CNC execution code. In the next article, I will explain this code in detail.

3. Execute processing: convert machine code into control signals, such as electrical pulse signals that control the movement of coordinate axes, the rotation of spindles, and other auxiliary control signals.

For example, on a CNC milling machine, the feed signal controls the feed pulses of the X, Y, and Z coordinate axes, drives the servo motor to move accordingly, and the rotation of the motor is converted into the translation of the worktable through the transmission mechanism until the processing operation of the part is completed.

It is worth mentioning that in order to present a perfect CNC part processing effect, an excellent CNC programmer is very important. Because there are many things to consider, a qualified programmer must write different software code instructions according to the existing machine system, and at the same time ensure that the software design meets the two major requirements of management and control.

Management Software and Control Software

Management software refers to tasks such as processing input, I/O, display, and diagnosis. In simple terms, it is the operating instructions that can be seen on the CNC console, while control software refers to tasks such as decoding, tool compensation, speed processing, interpolation, and position control.

In the actual CNC machining process, only a closely coordinated CNC system can ensure that each task can be carried out in parallel while maintaining the stability and real-time performance of the system.

In a CNC system with a single-core CPU, if you want to achieve multiple tasks at the same time, you must reasonably allocate the CPU usage time. You can use a loop structure to arrange tasks in a logical order and achieve multi-task parallel processing through the method of "resource time-sharing".

What Is the Principle of CNC Machining?

The principle of CNC machining is to control the machine tool through computer programs to automatically complete the machining process according to the predetermined machining path and machining parameters (this part of the work is generally completed by CNC programmers).

The core of CNC machining is to convert the CAD drawings of the machined parts into digital control instructions that the machine tool can understand, and pass these instructions to the machine tool through the CNC system to control the machine tool for automatic machining.

The principle of CNC machining mainly includes the following parts:

1. Design and programming: This part is usually designed and programmed by experienced CNC programmers according to the CAD drawings ordered by customers.

In this process, the more complex the part, the more complex the tool path required. If the optimal tool path is not written well, the tool will break during the actual product processing, which is very dangerous.

2. Data transfer: When the programmer completes the first step, the current data must be transferred to the CNC operating system. This is a solution. Most data transfers are carried out by copying USB flash drives.

3. Processing execution: This part of the work is usually done by CNC operators.

4. Inspection: Before the CNC tool mills or cuts the material, it is necessary to simply start the program route compiled by the CNC programming, including but not limited to cleaning the CNC machine (because the tool path used by the previous product is different, it is necessary to check the tool magazine to ensure that the worn tool can be replaced in time).

5. Adjustment: When the part is officially CNC machined, the tool needs to be calibrated to ensure that the processed product is within the tolerance range desired by the customer. CNC tolerance is very important for the CNC industry. In the next chapter, we will explain CNC tolerance in detail.

In fact, the principle of CNC machining has many steps, and all CNC work is for one thing, that is, to improve the production efficiency and adaptability of the machining center while ensuring machining accuracy and quality. ‌

What Are the Common Types of CNC Machine Tools?

In the CNC machining industry, the topic we mention most often is CNC machine tools. Different machine tools produce different parts and use different CNC machining technologies.

These CNC machine tool types are widely used in various manufacturing fields from precision part manufacturing to large part processing according to their specific processing capabilities and application range. The following are common types of CNC machine tools:

CNC milling machine: This machine is mainly used for processing CNC parts such as planes, curved surfaces, grooves, etc. It is characterized by multi-edge tools, which means that it is suitable for processing hard metals and industrial-grade materials and is also particularly suitable for cutting softer and delicate materials such as plastics, wood, and foam.

CNC milling machines are ideal for creating panels, plastic prototypes, and injection molding application molds. It is worth noting that according to the different raw materials processed, CNC milling machines are divided into plastic (as shown in Figure 1 below) and hardware (as shown in Figure 2 below).

The parts produced by these two different CNC milling machines will be different. I will make a sharp comparison of this CNC milling machine in another blog. Interested friends can click to check it out.

‌CNC Lathe‌: Also known as CNC Turning Center, it has a chuck and spindle. These machines usually have a 3-axis configuration and can achieve tight tolerances of ±4μm, which is very suitable for processing complex cylindrical shapes. CNC lathes are suitable for high-quality turning processes, including taper turning, knurling, drilling, cutting, and grooving.

‌CNC Laser Cutting Machine‌: Similar to CNC milling machines, but uses laser beams to perform cutting operations. It is suitable for high levels of cutting accuracy and a wide range of material compatibility. It is very suitable for cutting a variety of materials, including metals, plastics, and hardwoods.

It is worth noting that the materials cut by CNC cutting machines are best controlled at around 6mm and below 6mm so that the accuracy of the parts cut out will be guaranteed.

Friends who know about laser cutting know that laser cutting generates heat, and the thicker the raw material. The cut part will be dissolved, resulting in the actual product tolerance not meeting the tolerance standard marked on the drawing. Therefore, laser cutting is generally used in sheet metal manufacturing, because sheet metal parts allow such errors.

‌CNC plasma cutting machine‌: Similar to the laser cutting machine, but uses a plasma torch to perform the cutting operation, providing a high level of cutting accuracy and a wide range of material compatibility, especially suitable for cutting conductive materials.

‌CNC electrical discharge machining machine (EDM): Uses the electric sparks generated by metal tools to cut the workpiece into the desired shape, suitable for processing conductive workpieces, with high precision and high-quality cutting effects.

Usually, the CNC parts involved in electrical discharge machining have complex product structures and need to pass through the conductive metal copper "copper male" medium to accurately remove the desired cutting structure.

In Which Areas of Life Is CNC Machining Applied?

The importance of CNC manufacturing

For a person who has just entered the industry, if you can't feel the importance of CNC manufacturing, it is normal, and you are not alone. In other words, such feelings are real, which is also the original intention of we writing this article.

It is because of the emergence of CNC manufacturing that our ordinary life will be more full of technology. Technology is advancing, and the premise of technological advancement is that a large number of prototypes are needed for verification, and the emergence of CNC manufacturing just meets this demand.

1. Automobile manufacturing industry

For example, you need to understand that before a car is officially produced, it takes time to verify whether the automotive product data designed by the designer is accurate. A series of tests must be carried out, and mass production can only be carried out after passing the test.

And CNC manufacturing is undoubtedly the most suitable. The parts it processes are closest to the data that the designer wants, which involves a precision problem. Everyone should understand that one of the most commonly used areas of CNC machining is prototype verification, and the most accurate statement is prototype verification in the automotive field.

2. Aerospace field

The aerospace field has extremely high requirements for product precision and performance, so CNC machining also has important applications in this field. Aerospace product parts need to go through multiple complex processing procedures, including high-precision milling, drilling, turning, and other operations. CNC machining has high-precision and high-stability processing capabilities, which can meet the high requirements of product quality and performance in the aerospace field.

3. Mold manufacturing field

In the manufacturing industry, molds are important tools in the manufacturing industry. Through the automated processing capabilities of CNC machine tools, the efficiency and precision of mold manufacturing can be greatly improved.

4. Mechanical manufacturing field

In the process of mechanical manufacturing, if you want to perform precise cutting, milling, drilling, and other operations on various raw materials to obtain parts that meet the requirements, then CNC machining is the best manufacturing tool.

4. Electronic manufacturing industry

In the process of electronic product manufacturing, various small and precise parts need to be processed, such as integrated circuit boards, electronic components, etc. For such product parts with high-quality requirements, only through CNC processing can the products be controlled within a precise error range.

5. Medical device manufacturing industry

In real life, medical device products have extremely high requirements for precision and quality. Seemingly simple products need to go through multiple complex processing steps to obtain them, so CNC processing is also widely used in this field.

Through the above, everyone should have the most intuitive concept, that is, if you design some precise things in life, you can't do without CNC manufacturing. This is the importance of CNC manufacturing, which involves all aspects of our lives.

Is CNC Difficult to Learn?

There is a saying in China that "Nothing is difficult if you set your mind to it." It means that if you are very interested in something, you will achieve certain success in this field by constantly learning.

If you want to work in CNC manufacturing, you have two directions, one is a CNC programmer and the other is a CNC machinist (CNC operator). The difficulty of these two directions will be different, but you need to know that the premise of becoming a CNC programmer is that you have to have a certain understanding of the CNC operating system. This means that the CNC operator is the most basic threshold.

If you want to know the specific difficulty, in the next article, I will use "Is CNC difficult to learn" as the title to give you the most intuitive feeling of the difficulty of learning CNC.

Do you provide CNC machining services?

First of all, I am glad that you can see this, which shows that you are very interested in the CNC industry, and thank you for your high recognition of this article. In some of the above questions, you should feel most intuitively that we are professional in CNC manufacturing. This means that we provide CNC machining services, whether it is prototype production or batch manufacturing of parts, we can meet your project needs.

If you need it, just upload your CAD design drawing file, and we will provide you with a free quotation service. If you want to know more about our factory conditions, you can click here to enter; if you want to know more about consultation, please check out our business team page for one-on-one communication with a dedicated person.

For more CNC dynamic information, please pay attention to our website at any time, we will update it in real-time.