In the precision world of mold manufacturing, every step is crucial. After the mold design is completed, high-quality steel is the skeleton, and exquisite processing technology is the key to endowing the mold with soul. Among various processing methods, CNC (Computer Numerical Control) drilling and milling technology is undoubtedly one of the most widely used and high-precision processes in modern mold manufacturing. Today, let's step into the world of CNC and explore its mysteries in mold processing.

What is CNC?

     CNC， Computer Numerical Control (CNC) is a technology that uses computer programs to control machine tools for machining. Simply put, it is to "translate" the designed mold drawings into a "language" that computers can understand, and then have the machine tool automatically and accurately cut, drill, and mill according to instructions, ultimately completing the manufacturing of mold parts.

The role of CNC in mold processing
1.High precision machining: CNC machine tools can achieve micrometer level machining accuracy, ensuring that the size and shape of the mold meet the design requirements.
2.Complex surface machining: CNC machine tools can easily handle complex surfaces and irregular structures that are difficult to achieve by traditional manual labor.
3.Efficient production: CNC machine tools can work continuously for 24 hours, greatly improving production efficiency and shortening the manufacturing cycle of molds.
4.Consistency: CNC machining ensures high consistency of mold parts, reducing the difficulty of assembly and debugging.

The process of CNC machining
Programming: Professional CNC programmers write detailed machining programs based on mold drawings and processing requirements.
Material preparation: Install the rough processed mold steel on the CNC machine tool.
Processing: Start the CNC machine, and the machine will automatically perform milling, drilling, boring, and other operations according to the preset program.
Testing: After processing is completed, the size and surface quality of the mold parts are tested to ensure that they meet the design requirements.

Precautions for CNC machining
CNC machining is the bottleneck of the entire mold manufacturing process. Unreasonable arrangement of machine tools (large machines and small parts) and unreasonable processes (CNC machining for wire cutting and drilling machines) can lead to low machining efficiency and increased machining costs.

Tool selection: Choose the appropriate tool based on different materials and processing requirements to ensure processing efficiency and quality.
1.The cutting tool should be securely clamped and not too short in the handle.
2.Before each cutting, it is necessary to check whether the cutting tool meets the requirements. The length of the cutting tool should be determined according to the machining depth indicated in the program sheet, generally slightly longer than the machining depth value by 2mm, and consideration should be given to whether the tool holder collides.
3.When using an extended cable nozzle, it is particularly important to understand the depth of the blade and the required length of the blade.
4.Before installing the cutting head on the machine, the taper fitting position should be wiped clean with a cleaning cloth, and the corresponding position of the machine tool sleeve should also be cleaned to avoid iron filings on the fitting surface affecting accuracy and damaging the machine tool.
5.Usually, the tool length is adjusted using the tip alignment method (in special cases, the tool is aligned within the tool), and the instructions on the program sheet should be carefully checked during alignment.
6.When the program is interrupted or needs to be re aligned, attention should be paid to whether the depth can be connected to the front. Generally, the depth can be adjusted by 0.1mm first, and then adjusted according to the situation.
7.Rotating detachable cutting heads, if using water-soluble cutting fluid, should be lubricated with oil for several hours every half month for maintenance, which can lubricate the internal components of the cutting head and prevent wear.
8.During the machining process, it is necessary to pay attention to the wear of the cutting tools and replace the cutting particles or tools appropriately. After replacing the cutting particles, pay attention to whether the joint boundaries of the machining match.

Cutting parameters: Reasonably set cutting speed, feed rate, cutting depth and other parameters to avoid tool wear and workpiece deformation.

Cooling and lubrication: During the machining process, sufficient cooling and lubrication should be carried out to reduce cutting temperature and extend tool life.

Cooling and lubrication: During the machining process, sufficient cooling and lubrication should be carried out to reduce cutting temperature and extend tool life.

Coordination between NC and other processing methods
In mold manufacturing, CNC often does not work alone, but cooperates with other processing methods. Therefore, unless otherwise specified, it is necessary to consider the machining compensation allowance for subsequent processes.
Wire cutting: used for machining small gaps and irregular holes that are difficult for CNC to reach.
EDM (Electric Discharge Machining): Used for machining high hardness materials and complex surfaces.
Grinding machine processing: used to improve the surface smoothness and dimensional accuracy of mold parts. 

conclusion
CNC technology is one of the core technologies in modern mold manufacturing, which provides strong guarantees for the quality and production efficiency of molds with high precision, high efficiency, and high flexibility. With the continuous development of technology, CNC machining will play an increasingly important role in the field of mold manufacturing.

Transferred from: Mold making and Plastics Research Society