Application of milling technology in CNC turning and milling center

The CNC turning and milling compound center is a multifunctional machine tool that can realize milling processes such as plane milling, drilling, tapping, and slot milling. It has composite functions such as turning, milling, and boring, and can realize the concept of completing the processing of complex parts with one clamping. For ease of reading, we will sometimes refer to the CNC turning and milling compound center as a CNC milling machine in this article.

The movement of the CNC turning and milling compound center tool includes four basic movements: milling cutter rotation, workpiece rotation, milling cutter axial feed, and radial feed. According to the different understandings of the purpose of the needs and process requirements, and the different relative positions of the workpiece rotation axis and the tool rotation axis, the CNC turning and milling compound center can be mainly divided into Axial turning and milling machine, orthogonal turning and milling machine, and general milling machining. Among them, Axial turning and milling is the most widely used milling machining method. Axial turning and milling machining can process the outer cylindrical surface and the inner hole surface because the milling cutter and the workpiece rotation axis are parallel. It is usually a 3-axis CNC turning and milling compound center of X, Z, and C.

cnc turning and milling 1
cnc turning and milling 1


Axial turning and milling

Axial turning and milling has a large processing range and can complete external cylindrical surface processing as well as internal hole surface processing because the Axial turning and milling tool is parallel to the workpiece rotation axis. However, this process also has shortcomings, that is, the tool’s longitudinal and stroke will be limited, and this is mainly affected by the fact that the milling cutter diameter is smaller than the radial size of the spindle box. If this situation occurs during the processing, the processing technology should be changed in time. If Axial turning and milling is continued, it will not only affect the quality of parts and components and fail to meet production requirements but may also cause damage to some equipment.

Orthogonal turning and milling

Orthogonal turning and milling means that the rotation axis of the milling tool is perpendicular to the rotation axis of the workpiece, and the cutting trajectory of the milling tool is a spatial curve with a more complex shape. When this process is applied, the instantaneous cutting depth and cutting thickness will change with the change of the tool axis and rotation direction. For milling processing, the processing process of some parts is very complicated, multiple processes will be applied, and different process parameters will also be different. To fully ensure production quality, the parameter relationship should be straightened out first, and various process parameters should be reasonably combined. If the Orthogonal turning and milling function is fully utilized in the production process, the surface processing quality of milling can be effectively improved.

Advantages of CNC turning and milling compound center processing

Shorten the manufacturing process chain of parts and improve production efficiency.

A variety of special tools can be installed, and the new tool arrangement can reduce the tool change time and improve the processing efficiency. The milling machining can complete all or most of the processing procedures in one clamping, thereby greatly shortening the manufacturing process chain of parts. In this way, on the one hand, the production auxiliary time caused by the change of clamping is reduced, and at the same time, the manufacturing cycle and waiting time of the tooling fixture are reduced, which can significantly improve production efficiency.

Reduce the number of clamping times and improve the processing accuracy.

The reduction in the number of clamping times avoids the accumulation of errors caused by the conversion of positioning references. At the same time, most of the current milling machining equipment has the function of online detection, which can realize the in-situ detection and precision control of key data in the manufacturing process, thereby improving the processing accuracy of parts; the high-strength integrated bed design improves the gravity processing capacity of difficult-to-cut materials; the machine tool is equipped with an automatic feeding device, which can realize automatic feeding to be continuous, basically realizing the assembly line operation of a single machine tool.

Reduce floor space and production costs.

The compact and beautiful appearance design improves the space utilization method, and maintenance and repair are more convenient to give customers the greatest satisfaction. Although the price of a single turning and milling composite processing equipment is relatively high, due to the shortening of the manufacturing process chain and the reduction of equipment required for parts, as well as the reduction of the number of fixtures, workshop floor space, and equipment maintenance costs, it can effectively reduce the overall fixed asset investment, production operation, and management costs.

control panel 1
control panel 1

Application analysis of milling processing technology

Analysis of milling processing elements of CNC turning and milling center

Before carrying out CNC turning and milling processing, it is necessary to analyze various factors in this regard, because the CNC programming module is relatively complex, and the overall application effect needs to show technicality and flexibility. Therefore, it is necessary to consider machine tool factors, workpiece factors, tool and fixture factors, etc., as follows:

1. Analysis of machine tool factors.

This aspect is mainly based on machine tool power, machine tool coolant, and machine tool maintenance. The quality of the CNC turning and milling compound center itself, such as hardness and power, needs to be determined during the inspection. If these indicators do not meet the standards, the product quality cannot be ensured during the actual product processing process. As for the coolant, first of all, it is necessary to scientifically select the coolant according to the actual needs, and then pay attention to the flow of the cooling medium. If the coolant is not used during production, the operator should do a good job of daily maintenance of the milling cutter to avoid jamming during actual application;

2. Workpiece factor analysis.

When applying CNC programming technology, the workpiece factors should be fully considered, including the assembly status of the workpiece, repeated positioning, and especially positioning, which must be fully ensured to be accurate, otherwise the product is very likely to have defects. In addition, the tools and materials should be reasonably allocated to ensure that the workpiece size, blank size, surface quality, and other aspects meet the production requirements;

3. Tool and fixture factor analysis.

First, the milling cutter diameter should be determined, and secondly, the forward angle blade should be selected as much as possible, because this blade can not only reduce power consumption, but also improve the smoothness of the plane, and then select the tool, with the product production requirements as the indicator, to ensure the product production accuracy as the purpose, scientifically select the tool shape and material, and finally determine the main inclination angle.


Generally, countries have extremely strict requirements for the machine tool industry, not only requiring the production quality of various parts but also strict requirements for the operation specifications of CNC turning and milling compound centers. During CNC milling operations, human intervention should be avoided as much as possible, and all preparations should be done.

First, the workbench and fixtures need to be cleaned. Although CNC milling is mainly based on the operation of mechanical equipment, there are still many operators on site to assist in production. In order to ensure the life and health safety of personnel and reduce equipment failures, the site must be cleaned well. Because metal fragments are generated when the CNC turning and milling compound center is running, the fragments are very sharp. If they are not cleaned in time, it is easy to cut the operator, and the longer the metal fragments stay on the workbench, the more it will affect the product’s accuracy. Timely cleaning can effectively avoid such situations.

cnc turning and milling center 1
cnc turning and milling center 1

In addition to cleaning the workbench, the fixture is also a key cleaning object. The jaws, base, clamps, etc. are prone to sticking to small iron filings. If they are not handled in time, the production accuracy will inevitably be reduced when used again. If these fixtures have bulged, the working state of the fixture itself will continue to decline, and even some products will be scrapped and reworked, which will not only cause economic losses to the manufacturing company but also affect the processing progress.

Secondly, the blanks need to be checked, which can directly affect the machining accuracy of the machine tool. When checking, the main work content is whether there is any damage to the parts. If the parts are found to be damaged, they should be replaced immediately.

Processing technology analysis

Both CNC milling and manual milling belong to mechanical manufacturing processes, while CNC uses computer programming to realize automatic control of the processing process. There are great differences between the two. For CNC milling technology, whether the preparation process is reasonable will determine the success or failure of CNC milling technology. The following aspects should be done under this process:

1. Dimensioning.

When designing and programming, the advantages of CNC technology should be flexibly applied to clarify the dimensions and positions of all points, lines, and surfaces of the product, and do a good job of marking;

2. Analyze elements.

As a programmer, he should first clarify the various influencing elements of the process, understand the parameter relationship, and ensure the rationality of programming. During the product design process, the designer should check the drawings in detail. If any problems are found, they should be reported to the superiors in a timely manner, and timely adjustments should be made after feedback.

3. Accurate positioning.

Since the processing procedures in the CNC milling process are relatively concentrated, it is particularly important to use the positioning work under the same benchmark. The accuracy of each positioning must be ensured, otherwise it will inevitably harm subsequent processing operations;

4. Unified type and size

The operation of a CNC milling machine should maintain continuity and avoid frequent interruptions of operation. In addition, the quality of the tool should be fully guaranteed. After the tool is determined and installed, daily care should be done to reduce the number of replacements. At the same time, the processing time should be shortened through various means. To achieve the above purpose, the form and size should be unified first, so that large-scale production can be achieved. However, it should be noted that some parts have special requirements for the shape of parts in production. For example, if a geometrically symmetrical shape is to be reflected, this operation can be completed through the CNC mirror function to reduce the trouble of CNC milling programming.

Analysis of clamping and positioning of parts

Before formal production, the CNC milling machine should place the workpiece on the corresponding fixture or machine tool, and then fix it to avoid displacement of the workpiece due to vibration during the processing. To improve the effect, the operator should have the ability to operate the equipment flexibly and clamp it once. If the clamping is not successful once, the operator needs to make manual adjustments. However, it is difficult to ensure accuracy through manual operation, and the operation speed is slow and dangerous. Therefore, this situation will be avoided as much as possible in actual production activities.

Determine the selection of CNC milling machine tools and cutting amount

Whether it is a tool or cutting amount, if the selection is unreasonable, it will affect the processing effect of the machine tool. In addition, the selection of tools during transportation operations will also affect the processing accuracy. Therefore, when selecting tools, it is necessary to start from the processing perspective, especially for CNC milling machines, the tools used must have the advantages of high precision, high strength, high rigidity, high durability, easy installation, and easy adjustment.

When in a processing environment, the specific requirements of workpiece processing are the only criterion for tool selection. Generally speaking, when selecting tools, a method combined with the geometric parameters of the workpiece is adopted. However, if it is a closed keyway, this method will be difficult to play a role. At this time, the keyway milling cutter should be used as the main tool. If the product is required to be refined, the four-sided blade should be used as the main tool.

When determining the cutting amount, first of all, it should be clear what the main influencing factors in this aspect are, such as cutting amount, cutting speed, and spindle speed. If you want to determine the milling machine, you should also consider its application life. There are two types of service life, one is the minimum economic life and the other is the maximum working life. Many machinery manufacturing companies will take economic benefits as the main consideration when accepting orders, but if the production task is too urgent, the optimal cutting power must be the primary condition.

Select CNC milling tools and feed methods

If CNC milling operations want to fully improve the quality of machine tool processing, the tool path must not be ignored. The tool path often directly affects the process effect. When selecting the tool path, the machining accuracy of machine tool parts and the matching degree of external roughness are both influencing factors. At this time, only by shortening the tool running trajectory as much as possible and reducing the empty edge in the tool path can the processing effect be guaranteed. If two adjacent tool paths are connected with a ramp, the arc radius needs to be increased to avoid direct intersection. At this time, the tool can automatically track the next processing route.

If the tool paths are the same, measures should be taken in terms of the arc radius to keep it in motion at all times. The application of this method can not only ensure the smoothness of the CNC milling machine tool position trajectory but also reduce the resistance of the tool during operation and avoid tool wear.

The arc transition process has a good application effect in this regard because it can effectively complete the workpiece tangent operation and comprehensively improve the quality of CNC milling. The range of tool-feeding methods is small, usually between longitudinal and spiral methods. The longitudinal feeding method is more harmful to the tool because the cutting force of the milling cutter and mold is greater than that of the spiral method.

Therefore, the spiral method is more likely to be selected in actual production activities. When applying this feeding method, it is necessary to scientifically set the cutting amount, reasonably set the screw diameter, and standardize the operation process to avoid damage to the tool due to illegal operations or unreasonable operations.

Optimize the CNC milling programming process

In CNC milling projects, CNC machine tools can often play a huge role. Therefore, in addition to making reasonable choices, we should also pay attention to programming work and continuously optimize the CNC milling programming process according to industry needs.

First, adopt standardized programming methods and specifications to ensure the consistency and efficiency of the programming process, such as using unified naming rules, annotations and documentation requirements, and following the conventional programming style;

Second, use computer-aided manufacturing (CAM) software or other programming tools to write automated programs to generate CNC milling processing codes to improve programming speed and accuracy;

Then, adjust the tool path and trajectory planning, optimize the cutting path and feed rate to minimize cutting time, prevent collisions, and improve cutting efficiency and accuracy, and use advanced path optimization algorithms and simulation tools to ensure the rationality and optimization of cutting paths and sequences;

Finally, optimize cutting parameters such as cutting speed, feed rate, cutting depth, etc. according to different workpieces and processing requirements. Through experiments and tests, verify and adjust these parameters to achieve the best processing effect.

Measures to improve the quality of CNC milling processing

Standardize CNC milling processing and operation process

To fully improve the processing quality, it is necessary to standardize the CNC milling processing and operation process. In this process, advanced technology should be introduced as much as possible, the technical level should be improved, and the entire operation process should be optimized. Specifically, it can be started from the following aspects:

1. Carry out training for operators. In addition to continuously improving their operating level during the training process, their operating procedures should also be sorted out. If some operators do not strictly abide by the operating procedures during the actual production process, they should be dealt with in accordance with the corresponding management system;

2. Specify the use specifications of CNC milling machines, especially the two parts of processing and operation. The specific specification process is made into a document and issued to each department. Then, the on-site management system is formulated according to the document, and the managers of each department or the team leaders are responsible for supervision;

3. Improve the rationalization of programming procedures.

Under normal circumstances, there will be some differences in CNC milling technology in machine tool performance, programming and actual application. To reduce the negative impact of such differences, manufacturing companies should do a good job in resource allocation to avoid waste of resources.

Before this, it is necessary to investigate the existing equipment, including quantity, purchase years, current performance, whether there are any faults or damages, etc., and then reasonably arrange the equipment according to the actual processing needs. If some equipment is already in the scrap stage, it should be handled in time to avoid wasting storage space or confusing the infrastructure within the enterprise.

Improve the software and hardware system of machine tools

In CNC milling machines, the software system and hardware system can not only determine the ability of CNC processing equipment but also directly reflect the digital management level and software application ability of mechanical manufacturing enterprises. Therefore, if enterprises want to enhance work efficiency, they need to improve the software and hardware system of machine tools, optimize the programming program, and ensure the efficient and stable operation of machine tools. Specifically, we can start from the following aspects:

1. optimize the control system:

ensure that the control system of the machine tool has powerful functions and stability, and can support complex programming and processing operations, update and upgrade the firmware and software of the control system to improve performance, accuracy, and stability;

2. strengthen cutting parameter management.

Optimize the setting and management of cutting parameters, including cutting speed, feed speed, cutting depth, etc., to ensure that the cutting parameters match the material characteristics and workpiece requirements to achieve more efficient and more accurate processing;

3. strengthen simulation and simulation functions.

By enhancing the simulation and emulation functions of the machine tool software, the machining path can be virtually simulated and any potential conflicts or errors can be checked, which can reduce the downtime and human errors of the machine tool and improve production efficiency and quality;

4. improve the user interface of the machine tool software to make it easier to operate.

It is recommended to use a graphical interface;

5. is equipped with high-precision sensors for real-time monitoring of the status of the machine tool, the position of the workpiece, and feedback on the cutting process.

Apply three-dimensional surface machining technology

Three-dimensional surface machining is a machining process for three-dimensional cutting on a surface, which is used to manufacture parts with complex surface shapes. The process steps are generally as follows:

1. design surface model:

use computer-aided design software (CAD) to create or import the surface model to be machined. This can be point cloud data obtained from scanning a solid model, or it can be created through curve and surface modeling tools.

2. plan the machining path.

Use computer-aided manufacturing software (CAM) to generate the machining path for three-dimensional surface machining. According to the design model, select the appropriate tool, process parameters, and cutting path.

3. select the tool.

According to the processing path and the characteristics of the surface, select the appropriate tool for milling. Usually use ball-end tools, spiral tools or special-shaped tools to adapt to the shape of the surface.

4. set cutting parameters.

Determine the cutting parameters such as cutting speed, feed speed, cutting depth, and cutting direction. The selection of these parameters should comprehensively consider the hardness of the material, the performance of the tool, and the requirements of the workpiece.

5. Surface treatment and inspection.

After completing the three-dimensional surface processing, surface treatment such as polishing and painting may be required to achieve the required surface quality.


The CNC turning and milling center integrates multiple processing technologies such as turning and milling to achieve one-time clamping and multi-process continuous processing of complex parts, greatly improving production efficiency and processing accuracy. It is widely used in aerospace, automobile manufacturing, mechanical processing, precision instruments, and other fields, and is suitable for a variety of processing needs such as complex surfaces, polyhedral parts, and high-precision parts. In modern manufacturing, the milling processing technology of CNC turning and milling centers plays an irreplaceable and important role, in promoting the continuous progress and development of manufacturing technology.

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