CNC technology is a key driver of the industrial revolution, with CNC milling being the most widely used method. Its high precision, efficiency, and flexibility make it essential in industries like aerospace, automotive, mold production, and medical devices, improving product quality and production efficiency.

What is CNC milling?

CNC milling is a subtractive process where computer-controlled tools remove material to shape the workpiece. We achieve this process by using a machine called a CNC milling machine or CNC mill.CNC milling uses pre-programmed instructions to control the tool’s movement and cutting path for precise and consistent results.

In CNC milling, the workpiece is fixed on the machine’s worktable, while the tool rotates to cut. The tool moves along multiple axes to process complex shapes and features. Industries like aerospace, automotive, electronics, and medical devices widely use CNC milling for efficient, high-precision parts production.

How CNC Milling Works

Before CNC was incorporated, operators performed the controls on the milling machine manually. This gave a lot of room for error. The final product appeared in the machinist’s mind or vision, similar to the way an artist draws a picture. However, with the addition of CNC, milling became a highly accurate and precise process involving several steps. There are four sequential steps involved in creating a CNC-milled part:

1. Design 3D Model

During the design stage, engineers create the three-dimensional shape of the part using computer-aided design (CAD) software. Design engineers draw the model based on functional requirements, refining every detail. The software allows for adjustments to size, shape, and features to ensure that the design is accurate and correct.

2. Convert the model to machine code

Import the designed 3D model into the CAM software to generate the machine code (G-code) for the CNC milling machine. In the CAM software, set machining parameters like tool path, feed rate, and spindle speed, then convert them into machine code. The G-code is sent to the CNC machine’s control system to perform the machining task accurately.

3. Set up the CNC milling machine

When setting up the milling machine, first select the appropriate tool and install it on the spindle. Next, firmly fix the workpiece material on the table to ensure that it is stable and motionless. Set the zero point to accurately calibrate the workpiece position for processing along the predetermined path. Finally, check all settings and connections to ensure that the equipment is operating properly.

4. Perform actual milling

During the actual milling process, the CNC milling machine starts cutting according to the preset program and tool path. The tool removes material from the workpiece at a set speed and feed rate, while the operator monitors the process for accuracy and abnormalities like vibration or noise. The cooling system sprays cutting fluid to maintain temperature and improve accuracy, extending tool life.

Materials that can be CNC milled

1. Metal materials

Common metal materials in CNC milling include aluminum, steel, and titanium. Aluminum is widely used in the aerospace and automotive industries because it is lightweight, moderately strong, easy to process, and has good thermal conductivity. Steel is chosen for manufacturing mechanical and structural parts due to its high strength and wear resistance. Titanium is selected for high-performance applications, such as medical implants and aerospace components, because of its strength-to-weight ratio and corrosion resistance. These metal materials require the selection of appropriate cutting parameters and tools to ensure machining quality and tool life.

2. Plastic materials

CNC milling is also suitable for a variety of plastic materials, including ABS, polycarbonate (PC), and polyoxymethylene (POM). ABS offers good strength and toughness, making it commonly used to manufacture housings and structural parts. Polycarbonate, with its high transparency and impact resistance, finds wide use in optical components and protective covers. Polyoxymethylene is suitable for the processing of precision gears and bearing seats due to its high rigidity and low friction. To prevent thermal deformation and melting of plastics, manufacturers use lower cutting speeds and feed rates.

Advantages and applications of CNC milling

1. High precision

CNC milling technology can achieve micron-level processing accuracy. Computer control precisely manages the tool movement and cutting path, ensuring size and shape consistency.

Application:  CNC milling manufactures precision aircraft structural parts and engine components in aerospace. In addition, manufacturers require high-precision processing in medical device production to ensure the function and safety of the equipment.

2. High efficiency

CNC milling can achieve high-speed processing and automated production. The machine tool improves efficiency and shortens the production cycle.

Application:  In the automotive manufacturing industry, manufacturers use CNC milling to produce engine parts, gearbox parts, etc. Efficient processing can quickly respond to market demand and improve the overall efficiency of the production line.

3. Flexibility

Through programming, CNC milling machines can quickly switch processing tasks to adapt to different product designs. This flexibility makes it very suitable for small-batch, multi-variety production needs.

Application: CNC milling quickly adjusts parameters to produce various molds, like injection and stamping molds, to meet customer needs.

4. Stability

CNC milling is less affected by human factors, ensuring consistent and stable processing quality. The automated operation of the equipment reduces human errors and ensures product consistency.

Application: In the electronics industry, CNC milling processes precision components and connectors, requiring stable quality to ensure product performance and reliability.

5. Versatility

CNC milling is capable of performing many types of processing, including plane milling, slot milling, hole processing, and contour processing. This enables it to cope with a variety of complex processing tasks.

Application: CNC milling processes complex mechanical parts like gears, brackets, and housings with intricate geometries and requirements.

Conclusion

CNC milling technology is essential in modern manufacturing, offering precision, efficiency, and flexibility for various industries. It provides reliable solutions for applications like aerospace and medical devices. Despite challenges like high equipment costs and programming complexity, its future remains promising with ongoing technological advancements.

The ongoing development of intelligent, composite, and eco-friendly technologies will enhance CNC milling’s capabilities and sustainability y. We look forward to more breakthroughs in this field to promote the manufacturing industry to a higher level. I hope this article offers valuable insights to help readers better understand and apply CNC milling technology.