What is CNC Machining

CNC machining, or Computer Numerical Control machining, is a manufacturing technique that uses computer software to precisely control cutting tool motion in a way that makes it possible to produce high-accuracy parts.

It guides the cutting tool to remove the workpiece according to a predetermined path and speed, thus creating finished components to design standards. In simpler terms, CNC programming is the one that dictates the path of the cutting tool movement, ensuring full control during machining.

For those who want to do this trade in the future, don’t be afraid of so-called complex stares. Any material can be lowered to the simplest geometric shapes. All that is required is to develop a sequence of programs through the rational use of machine tools and other cutting instruments and measuring devices to machine the parts with efficiency, speed, and accuracy.

The History of CNC Machining

The history of CNC began around the 1940s with the invention of the first numerically controlled machine tool. As time passed, such machine tools grew more in number and also became more complex so that they could cater to the strict requirements of various industries such as aerospace, automobile manufacturing, and national defense.

Even then, however, the original CNC machine tools still required manual input of instruction and were extremely limited in functionalities.

It was not until the 1970s that computers changed the manufacturing industry with revolutionary technologies, producing the first numerically controlled machine tools. These advanced machine tools incorporated computer-based control systems with capabilities to process information at record accuracy and speed. With this new technology, CNC operators could enter instructions directly into the machine tool, which would proceed to automatically perform the operations, greatly simplifying the manufacturing process.

This was just the start of the development of numerically controlled machine tools. With ongoing technological advancements, improved software and hardware have been created, and new tooling options and materials have also provided manufacturing units with more options.

At present, numerically controlled machines have been widely used in many industries and can be utilized to produce different high-precision products, demonstrating their large production capacity and wide application value.

Common CNC Operations in the Entire Industry

CNC machining is highly flexible, and its working process will be adjusted according to various actual needs. For easy models, a single machining process, like milling, can be sufficient to complete the job. However, for complex models, various machining technologies are required.

CNC Milling Machines

CNC milling is a machining operation which offers high accuracy and flexibility. It is able to cut away accurately excess parts of a solid mass of material in order to acquire a definite form or shape. In the cutting process, it is the task of the CNC system to keep track of the multi-point cutting tool (milling cutter) to perform with very high precision. Workpiece is also tightly clamped on the workbench, with the milling cutter moving at tremendous speed to bite into the material systematically. CNC milling is extremely good at producing flat surfaces, but its ability does not stop there because it can also create more complex geometric shapes.

It is especially fascinating that CNC milling machines have the choice of intermittent cutting, which would mean that these machines can switch between different phases of machining when and where it is necessary to efficiently build advanced and complex geometries. Thanks to constantly increasing technology, CNC milling has encircled all kinds of milling machines beginning from 3-axis to 4-axis to even 5-axis.

• 3-axis Milling: With the linear movement along X, Y, and Z axes, basic milling operations such as planing and drilling can be achieved. It’s a very popular method due to its ease in comprehension as well as due to the fact that it is suitable for purposes where basic shape and projects have to be created. It also possesses some level of limitation in creating complex shapes of geometry and thus is ideal for projects of less complex nature.
• 4-axis Milling: Through the addition of a turning axis, this technology is able to perform more complex machining operations compared to 3-axis milling. This advanced technique is superior to dealing with angular cuts and more complex geometries, and the scope of use for Computer Numerical Control (CNC) machining is much broader. It is particularly valuable and important for high-accuracy components requiring exceeding the precision ability of 3-axis milling machines.
• 5-axis Milling: Five-axis CNC machining is the latest CNC machining state of the art. It is a process which is capable of traveling on five axes at a time, offering incredible precision of machining and complexity. In industries where maximum precision is the goal, it is invaluable in producing complicated shapes with hard tolerance specifications. Not only does the process simplify production, but it also offers effective and precise machining by eliminating many setups during production.

CNC Turning

CNC turning is a highly effective metal machining process used primarily for processing cylindrical parts and may also be used to process raw materials with square and hexagonal cross-sections. Its concept centers around using a computer-controlled lathe, with the assistance of multiple rotating cutting tools, to cut and shape the workpiece with precision until a cylindrical shape with the desired specification is obtained.

The lathe is characterized by its high level of versatility and precision machining capability, which is supported by a large range of spindle and speed control capabilities. The operation can be carried out on vertically and horizontally mounted lathes, each of which is suitable for different workpieces and specific machining requirements.

There are mainly two types of machines:

• CNC Lathes: This machining process is ideal for precision turning, especially for the manufacture of high-precision cylindrical components. It uses stiff cutting tools to machine the turning workpiece and is very capable of generating simple to moderately complex shapes. This technology has been widely used in industrial applications in industries such as the automotive and aerospace industries due to its outstanding machining performance and accuracy.
• CNC Turning Centers: It integrates the turning process with a number of other operations such as milling and drilling to form a multi-functional machining process. The multi-tasking processing function enables the completion of the entire production process of complex parts in a single setup, significantly improving the efficiency of production and the precision of machining. For industries that require complex and multi-faceted components, for instance, advanced manufacturing, this machining process is highly significant.

CNC Drilling

Drilling is one of the significant manufacturing operations that can create threaded holes of varying sizes in workpieces. Because of the computer’s precise control of the movement and speed of the drill bit, the operation has been automated.

CNC drilling technology is used extensively in the majority of industries, including printed circuit boards, metal components, and plastic goods. In contrast to manual drilling methods using traditional manual drills, CNC drilling possesses some advantages, including higher precision, high repeatability, and very good production efficiency.

CNC Routers

The general operation mode of a CNC router is much the same as a common milling machine.

During the milling process, the workpiece remains stationary, but the spindle oscillates in various directions along a prescribed path. Note should be taken of the fact that because the milling is practically applied in fairly soft material, the revolution speed of the spindle can be fairly slow. There are numerous CNC milling machines, and some of them are bench milling machines, gantry milling machines, and mobile gantry milling machines. The specific machine tool and cutting tool to be utilized must be established on the basis of the specific workpiece properties and the intended final product.

Electrical Discharge Machining (EDM)

Electrical Discharge Machining (EDM) is a process in which the electric spark discharge process is used to remove materials and obtain complex geometries and forms.

The essence of this process is the electric sparks between the workpiece and the electrode. The technicians will submerge the workpiece in a dielectric fluid, which not only insulates the electrical energy but also enables accurate control of the electric sparks. When the electric sparks are emitted, the local area of the workpiece will rapidly vaporize and serve as the function of material removal and shaping the desired shape.

EDM is primarily classified into two categories: wire EDM and die-sinking EDM. Die-sinking EDM (Sinker EDM) employs an electrode that continuously becomes used for generating electric sparks, whereas wire EDM employs a thin reciprocating wire that produces electric sparks.

CNC Plasma Cutting

CNC plasma cutting is a high-technology manufacturing process widely used on large-scale industrial processes, and it is most renowned for high-speed and precise cutting of electrically conductive materials such as steel, stainless steel, aluminum, brass, and copper. CNC plasma cutting uses a plasma torch to establish a high-energy plasma arc between the electrode and the workpiece, which has the ability to melt and vaporize the material at the contact point. In this process, there is a significant role played by a high-pressure gas stream (e.g., air or nitrogen). It is the one that efficiently sweeps away the melted material from the cutting zone so as to maintain the cleanliness and sharpness of the cutting edge and reduce material deformation or coloration.

With its amazing versatility, the CNC plasma cutting technology can serve the cutting need of the varied materials in thickness, either thin or thick, and thereby expands its potential scope of applications in the manufacturing sector. Compared to the other cutting processes, plasma cutting has excellent economical advantages, for instance, is cheaper to operate. With economy, speed, and accuracy as its three folds, CNC plasma cutting technology forms an integral component of sophisticated manufacturing in such sectors with very high demands on both efficiency and precision.

CNC Laser Cutting

CNC laser cutting is one giant step ahead of the rest of industrial manufacturing, extremely well-recommended for its perfect precision and unbelievable speed. It is being equipped with sophisticated lasers, including CO2 lasers, neodymium lasers (Nd lasers), and neodymium-doped yttrium aluminum garnet lasers (Nd:YAG lasers), that can effectively vaporize materials, making clean and precise edges. As this technology can treat a range of materials, its application range is extremely broad, which has also encouraged its popularity in a range of industries.

Not only does the accuracy of CNC laser cutting appear in one step, but its great repeatability is also a giant bonus to mass production. Its stable accuracy is undoubtedly a giant benefit to industries with ultra-high accuracy needs like aerospace and automotive. Furthermore, CNC laser cutting is also highly efficient. Not only can it reduce material loss, but also accomplish cutting tasks with high accuracy. The operation also allows the clamping workpiece process and lessens the chance of workpiece contamination, therefore enhancing the overall efficiency of production. With its capability of performing precise cutting and holding tight tolerances, CNC laser cutting has become an indispensable tool in modern manufacturing.

The Core Process of CNC Machining

• CAD Design: Employ software (e.g., SolidWorks, AutoCAD) to model the 3D part in CAD. 

Computer-Aided Design (CAD) software is utilized by engineers to firstly create a 3D workpiece model. The model design is transformed into numerical control codes (e.g., G codes) and data parameters like cutting parameters and machining paths by Computer-Aided Manufacturing (CAM) software.

• CAM Programming: Load the model into CAM software (e.g., Mastercam, UG) to produce tool paths and G codes.

The written numerically encoded program is uploaded to the CNC machine tool control system with the help of a data interface transmission device (e.g., USB, Ethernet, etc.). The control system executes and follows these codes and creates control signals to make the machine tool’s moving components move.

• Machine Tool Setup: Align the workpiece, assemble the cutting tool, input the program, and prepare the machine tool.

The numerical control program instructions are used by the CNC machine tool to automatically program and run the tool path. The moving parts of the machine tool (e.g., spindle, workbench, etc.) move along the trace set under control of the numerical control system to finish operations such as cutting, drilling, and milling on the workpiece.

• Machining Execution: The machine tool executes operations such as cutting, drilling, and milling automatically according to the program.

During machining, the CNC system will, in real time, monitor such factors as cutting tool location and workpiece location and the cutting force, and adjust accordingly to achieve quality and accuracy of machining. Certain advanced CNC machine tools also have online measurement and feedback systems that can detect errors in real time during machining.

• Quality Inspection: Use a Coordinate Measuring Machine (CMM) or laser scanner for detecting machining accuracy.

Main Application Areas

What are the Benefits of Choosing CNC?

As a next-generation machining technology, there are several benefits of CNC machining for human beings. The benefits of CNC machining are as follows:

• High Accuracy: Direct tolerances simply refer to the fact that the final products produced using precision machining will be of high accuracy. Precision machining is usually done for parts that require matching with other parts.
• Low Production Cost：Since precision machining never involve any deviations, there are fewer defective products. Hence, this process can cut down the rate of scrap parts significantly. Thus, the material cost is low. Further, the process of computer-aided manufacturing can lower the labor cost. The combined lowering in labor cost and material cost results in the production cost of CNC machining being lower than any other alternative.
• Speed and Efficiency: Precision machining makes use of high-speed robotics, which are able to manufacture parts more rapidly than manual manufacturing on traditional lathes. Additionally, the parts are high-precision and tight tolerance finishing, so secondary processing is not required. This can save the production time and improve the productivity and efficiency of the workshop.
• Complex Machining Capability: CNC machine tools have the capacity of complex machining (i.e., 3D surface milling, spiral cutting, and multi-axis simultaneous machining, etc.). They can control the motion of the cutting tool and workpiece with accuracy as per the pre-programmed program, which allows them to achieve the machining of complex shapes and structures.
• Safety: CNC machine tools replace human labor with a computer numerical control system and remove the risk factors of human error involved in the cutting process, which greatly minimizes the potential risks workers are subjected to when working with the machine tools. Workers can also be redirected to skill-based positions, for instance, CNC design operations.
• Reduction of Human Errors: Because a computer regulates the machining of CNC machine tools, the influence of humans on quality of machining is minimized. (Human errors are such as: for instance, fatigue, uneven operations, and judgments, which have a tendency to produce poor machining results.) CNC machine tools are able to reduce these errors and optimize the uniformity and accuracy of machining.

KESU’s CNC Machining Service

As one of the most significant technologies of modern manufacture, numerically controlled machine tools have played a great role in promoting industrial automation process. And on our side at KESU, we also have a team of highly experienced and professional technical experts. Each of them is an expert in the working abilities of the respective posts. In our opinion, KESU will be an ideal choice.

Conclusion

CNC machining is the basis of modern manufacturing. With computerized and automated technology, it has transformed production efficiency and product quality. With Industry 4.0 development, CNC machining is slowly changing to become more intelligent and integrated and one of the fundamental competitiveness of high-end manufacturing.