Shulou(Shulou.com)11/24 Report--

The original title: "which one is better when learning numerical control?" China. This article of No. 2 Middle School! "

Computer numerical control machine tool (computer numerical control machine,CNC) is a kind of material processing tool, which can cut whole pieces of raw materials into the desired shape of parts. CNC machine tools use software to control the movement of complex machines such as grinders, lathes and milling machines, and use these machines to cut materials.

These computer-aided manufacturing technologies can achieve many complex and accurate NC machining tasks, producing standard accessories and specially designed parts for the automotive, national defense and aerospace industries.

Although 3D printing and other augmentation manufacturing processes play a major role in the production of modern flexible devices, most daily necessities are still the products of highly automated weight reduction technology.

The mold of the plastic water bottle is made of CNC concave die technology; the independent drive system components of the car are milled to the exact size by CNC machine tools, so that all gears can closely mesh and achieve the best mechanical performance.

"it's quite possible that everything you come into contact with in daily life has been machined by machine tools," said Tony Schmitz, an engineering professor at the University of Tennessee at Knoxville. "if you've been on a plane-for example, a Boeing 747Fry-there are millions of machine-made parts on it that can be assembled before the plane can fly."

How do CNC machine tools work? CNC machine tools are as versatile and dynamic as many products processed by them. However, most CNC machines are controlled by two kinds of logic: open-loop or closed-loop systems.

In the open-loop CNC system, the operator will develop computer numerical control programs for the current task and use computer-aided design (CAD) software to generate g codes or working files. The computer then passes the correct steps to the controller and its connected servo motor.

These motors operate cutting tools such as turning tools or grinding tools along at least two axes (X and Y), but high-end CNC machine tools can improve accuracy and function by moving tool heads and other accessories around a few more additional axes.

The closed-loop CNC machine tool system provides feedback data to the display to solve the problem of inconsistency in the movement and cutting of CNC machines around raw materials. This kind of motor-display communication enables the closed-loop system to change the speed, position and feed speed of lathes and other CNC machine tools in real time.

The five main functions of CNC machine tools are some of the most common industrial applications of CNC machinery:

1. CNC cutting machines can cut raw materials accurately and efficiently, and they can apply two state-of-the-art cutting technologies: electrical discharge forming (sinker EDM) and WEDM (wire EDM).

The EDM machine uses the thermal erosion caused by the interaction between two electrodes, one of which is a copper or graphite electrode in contact with the tool, and the other is connected to a dielectric liquid impregnated with no material. The metal on the surface of the workpiece is melted by the local instantaneous high temperature produced by the discharge, creating a small pit. The workpiece is machined into the desired shape by constantly moving the discharge position. Surprisingly, the tool and the workpiece have never been in direct contact during the production process. WEDM works in the same way, except that it uses welding wire as a tool for precision cutting.

two。 The drilling CNC machine tool can drill holes accurately, and it uses rotary cutting tools (usually bits or high-speed water jets) to drill round holes in fixed workpieces. These holes are usually used to assemble screws.

3. Grinding CNC machine tools are usually equipped with grinding wheels to produce an almost completely smooth surface. The precision of this reduced grinding technology is much higher than that of any augmented manufacturing process, and the defect tolerance can be reduced to 1 / 10 of the width of human hair.

4. Milling CNC milling machines are similar to ordinary milling machines and other manual milling machines, using lathes, water jets or turning tools to remove excess materials from raw materials. CNC milling machines can move along multiple axes, so operators can perform horizontal, vertical, inclined and surface milling tasks with absolute precision. Because operators do not have to adjust and refix raw materials many times, these multi-angle cutting functions improve the efficiency of manufacturing complex wood, metal and plastic parts.

5. Turning is a CNC machine tool process that works similar to milling; however, instead of fixing the raw material on the machine base, it is connected to a high-speed rotating turning mechanism. The worker then uses a lathe or a CNC machine tool with similar accessories to remove a small amount of material until the raw material blank is made into the desired shape of the part.

What is computer-aided manufacturing software?

Both CAM and CAD software are important parts of NC machining. Wikipedia computer aided Manufacturing (CAM) software is an important part of NC machining process. It is the intermediary and interpreter of all computer-aided processing operations because it controls the manual and mechanical input and output of each stage of the processing process.

For example, a designer creates a 3D model of a project in computer-aided design (CAD) software and transfers files to CAM software. Then, the CAM software will interpret the model and generate m code or g code to convert the machining requirements of the project into a NC programming language. When the CNC machine tool is working, it will send the data back to the CAM software and show all the factors that may affect the processing result of the product.

A brief history of CNC machine tools NC machining can be traced back to technological advances during the industrial revolution in the mid-19th century, when manufacturing factories began to use cam-based lathes and milling tools to mass-produce guns, factory equipment and daily necessities. In the 1940s and 1950s, the original NC machining in the form of m-code punch cards began to replace manual control in specific tasks and began automatic manufacturing.

With the progress of digital computers and computer software in the 1970s and 1980s, more manufacturing tools can be controlled automatically, thus improving production speed and overall efficiency.

In the 21st century, CAM and CAD software and cutting-edge CNC machine tools provide a cost-effective way for small factories to produce a large number of complex parts. With the continuous development of machine learning and artificial intelligence, the manufacturing industry may continue to optimize processes and improve the level of automation.

What will NC machining look like in the future? When we first entered the "artificial intelligence revolution", it was easy to fantasize about a future world in which robots do all the work. However, processing professionals and engineering scholars understand that CNC processing requires skilled workers to ensure that everything is all right.

"it [computer numerical control] is a basic capability that will not disappear soon," Schmitz said. On the contrary, he believes that increased material manufacturing and reduced material manufacturing actually complement each other, so that "hybrid manufacturing" will become the mainstream NC machining process in the future.

Schmitz also said that this hybrid manufacturing would "first produce a preliminary part matrix with increased material, and then use limited reduced material processing to produce a smooth surface, which cannot be achieved by adding material."

However, one of the biggest obstacles facing NC machining in the future is the shortage of qualified skilled workers who are familiar with NC programming. As senior CNC professionals retire, few people enter the industry to take their place, and the shortage will only intensify.

"although historically, processing has always been considered a craft-craftsmen need years of training and practical experience to create the parts they want-I believe we will move from this state to a more automated processing environment," Schmitz said. " There will still be demand for manual processing in the future, but they will be very different from the beginning of NC machining technology in the 1940s and 1950s. "

Author: Mitch Ryan

Translator: Tibetan idiot

Revision: floor-sweeping monk

Original link: What Is CNC Machining?

This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: Mitch Ryan

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.