Current computer numerical control (CNC) machines follow a set of protocols based on the previous numerical control (NC) system first developed in the middle of the 20th century. With the advent of CNC machine tools, the metalworking industry began to rely on the use of paper tape punch applications (or "G codes") to program instructions for manufacturing parts. The use of CNC systems continued for decades, until the late 1960s when more advanced CNC programs became the industry standard.
CNC use before 1950
Although traditional NC programming was common in the metalworking industry in the 1950s, the basic form of the punch card system has been developed in the 19th century, when the system was used to control textile machines and play pianos, with similar simplifications Method, principle.
In 1949, a CNC tool manufacturer's lathe introduced the numbering band to control the machining process, but the manufacturer's response to the new technology was contradictory. After World War II, the U.S. Air Force sought a way to add higher component design accuracy to existing manufacturing methods. The search prompted John Parsons, president of the Parsons plant in Traverse City, Michigan, to develop a batch-to-batch manufacturing technique involving servo control. The servo control system is driven by the position data input into the computing device. The new method speeds up the manual process and improves machining accuracy.
1949 to 1964
From 1949 to 1952, Parsons and the Massachusetts Institute of Technology (MIT) developed an experimental machine capable of CNC contour milling. At the time, the electronics industry had not yet created a support system to help integrate new machines, so mass production of Parson's technology was impractical. However, in 1952, before the military, the aerospace industry, the machining industry and the media, a three-axis CNC milling demonstration was successfully completed. By 1964, there were more than 35,000 CNC machine tools in use across the country.
The evolution from punched tape to software programs
Initially, NC punch tape cards were created using a machine similar to a typewriter (called "flexowriter"). The punch card is fed into a large control unit adjacent to the machine and printed with a programming sequence called G-Code, which is named after the company that developed it, Gerber Scientific Instruments.
Until the late 1960s, when the first computer numerical control (CNC) machine came out, NC machines were industry standards. CNC technology follows the same principles set by the original digital protocol system, but replaces punching and printing methods with more advanced computer software programs. This new programming technology quickly replaced NC machining and became the industry standard. CNC is also the basis for subsequent processes, such as computer-aided design (CAD) and computer-aided manufacturing (CAM). The CAD/CAM design service is conceptually similar to the mechanical punch card system created in 1952, providing today's manufacturers with greater operational flexibility.
The development of numerical controllers
Numerical control machines in the 1950s and 1960s used vacuum tubes and mechanical relays as their main controllers. At that time, the controller was a "point A to point B" locator running along two axes. However, today's high-density integrated circuits are capable of creating three-dimensional shapes in a variety of designs and size ranges. Modern controllers can also communicate with users, and store and analyze program data.
Advanced CNC machinery can automatically monitor the quality of the work performed and transfer its findings to other parts of the processing process, such as the loading and unloading stage. If the controller is found to be defective or deviated from the expected product design, it can sometimes be corrected in real time by replacing blunt tools or notifying the manufacturer of any problems. This level of automation highlights the main difference between two conceptually similar programming methods: NC controllers must operate within the parameters of direct, simple tasks, while CNC programming enables the machine to analyze data and adapt to changing conditions. surroundings.
Advantages of CNC machining
Since computer-controlled machining has been developed for decades, current iterations are more advanced than any earlier forms including NC programming in terms of accuracy, automation, and production speed. Some of the benefits provided by the latest types of CNC machining include:
Complicated and complex parts manufacturing, with higher accuracy and faster turnover.
Semi-automatic or fully automatic quality control and equipment inspection system.
Shorten the setup and integration time of CNC machine tools, thereby increasing productivity.
The computer-controlled network reduces specific The number of machines required by the project.
CNC program modification function to improve adaptability and a wider range of processing tasks.
There is no need to perform long-term machining trials under the CNC program.
The application of CNC machining
Machined hydraulic parts
CNC machining is a manufacturing process that can form a variety of selected raw materials (such as metal, plastic, wood, foam, composite materials, etc.) into customized parts and designs. Because of the range of materials, precision, and functions and operations provided by the process, it can be used to manufacture parts and components for various industries and applications, including automotive, aerospace, agriculture, construction, hydraulic equipment, ships, and robotics.