What is the process of CNC machining?

Recently, the reporter visited the production workshop of a high-end precision manufacturing enterprise in Zhejiang and witnessed how computer numerical control (CNC) machining technology reshapes the manufacturing logic of modern industry with "one cut and one engraving". In the dust-free workshop with constant temperature and humidity, dozens of CNC machine tools are operating around the clock. The robotic arms accurately grasp raw materials such as aluminum and titanium alloys, and the tools cut with an accuracy of 0.001 mm. This almost "surgical" processing method is pushing the production of parts in the fields of aerospace, medical equipment, etc. into a new stage.

From drawings to physical objects: three-layer technical closed loop

According to the introduction of the technical director, CNC machining needs to go through a strict three-layer technical closed loop. First, engineers use 3D modeling software (CAD) to design the part structure and verify its mechanical properties through a simulation system; then, programmers convert the model into code instructions that can be recognized by CNC machine tools. Only one aircraft engine blade may contain tens of thousands of lines of code; finally, the operator needs to adjust the cutting parameters according to the material characteristics, and even the millimeter temperature difference caused by the tool speed needs to be included in the calculation.

The hard power behind the "micron-level" precision

In the company's quality inspection laboratory, the reporter saw a new energy vehicle motor housing that had just come off the production line. After the quality inspector scanned it with a laser measuring instrument, the screen showed that all aperture errors were less than 0.005 mm, equivalent to one twentieth of a hair. "This kind of precision is inseparable from the five-axis linkage technology." The director explained that the complex curved surfaces that traditional three-axis machine tools cannot complete can now be completed through the CNC system to synchronously control the five degrees of freedom of the tool. A single clamping can complete 360-degree processing, and the efficiency is increased by more than 70%.

Industry applications are broadened and technical bottlenecks are to be broken through

At present, the company's CNC products have been applied to high-end fields such as Long March rocket fuel valve bodies and artificial joint implants. However, according to the technical director, facing the processing needs of new materials such as ceramic-based composite materials, the existing tool loss rate is still high. To this end, the company is cooperating with universities to develop an adaptive CNC system that automatically corrects parameters by real-time monitoring of cutting vibration, and it is expected to be put into testing by the end of this year.

With the advancement of Industry 4.0, CNC technology is deeply integrated with the Internet of Things. In the central control room of the workshop, the large screen shows the energy consumption, progress and other data of each device in real time. The factory director revealed that by introducing digital twin technology, the trial production cycle of new products has been shortened from two weeks to three days. According to statistics from the industry association, the market size of CNC machine tools in my country will exceed 380 billion yuan in 2023, and the market share of domestic high-end equipment will increase by 12 percentage points compared with five years ago.

This manufacturing revolution, which started with computer code, is redefining "Chinese precision". When the coldness of machinery meets the rigor of data, it may be the key to breaking through the high-end manufacturing industry.