What is CNC machining? Processing steps, types, equipment, etc

What is CNC machining

CNC machining is a technology that uses computer control and programming to automate the machining operations of machine tools. In CNC machining, computers control the movement and operation of machine tools through pre written programs, achieving precise cutting and machining processes.

Traditional machine tool processing requires manual adjustment and control by operators, while CNC machining utilizes computers and specialized controllers to transform manual operations into automated processes. Through pre written programs, operators can define cutting paths, cutting parameters, working coordinate systems, and transmit this information to CNC controllers.

The CNC controller receives and interprets the instructions in the program, and then controls the axial movement, spindle speed, feed speed, etc. of the machine tool to perform precise cutting and machining operations. Due to the use of computer control, CNC machining has the characteristics of high precision, high efficiency, good repeatability, and strong flexibility.

CNC machining can be applied to various types of machine tools, such as milling machines, lathes, drilling machines, grinding machines, etc. Widely used in parts processing, mold manufacturing, aerospace, automotive industry, medical equipment and other fields in the manufacturing industry.

Numerical control machining is a technology that utilizes computer control and programming to dynamically control machine tools for precise machining, playing an important role in modern manufacturing.

Steps of CNC machining process

Firstly, design and draw the parts according to the requirements and requirements of the product. Designers use CAD software to create 3D models and 2D drawings, and define machining processes and cutting paths. Then, based on the design drawings and requirements, develop a processing plan, including selecting suitable machine tools, tools, and tool paths.

After developing a processing plan, convert the processing process into a CNC program. Programmers use CNC programming language to write programs that specify cutting paths, cutting parameters, working coordinate systems, etc. The written program will be loaded into the CNC controller.

Before actual machining, it is necessary to set up and prepare the machine tool. This includes installing and clamping workpieces, installing suitable tools and fixtures, adjusting the various axes and working coordinate systems of the machine tool, and ensuring that the initial positions of the machine tool and workpieces are correct.

After everything is ready, start the processing operation. By starting the CNC controller, loading the CNC program, and selecting the correct program to run, the machine tool will automatically process according to the specified cutting path and parameters in the program. The CNC controller will control the spindle speed, feed speed, tool position, etc. to achieve precise cutting operations.

During the machining process, it is necessary to maintain the cutting tools and adjust the cutting parameters according to the actual situation. Including tool replacement, tool compensation, adjustment of cutting speed and feed speed, etc., to ensure machining quality and efficiency.

After processing, quality control and inspection are required. Use measuring tools and equipment to inspect the dimensions, surface roughness, and other aspects of the processed parts to ensure that they meet design requirements and standards.

Optimize and improve the process based on actual processing conditions and quality inspection results. By analyzing processing data, adjusting parameters and process flow, improve processing efficiency and quality.

The CNC machining process requires a combination of knowledge of machine tools, programming, and machining technology, as well as an understanding of product requirements and material characteristics. By reasonably planning and executing machining processes, high-precision, high-efficiency, and stable machining processes can be achieved.

Types of CNC machining operations

CNC milling

CNC milling is one of the most common CNC machining operations. By rotating the tool, the material is removed from the workpiece to achieve cutting operations for machining shapes. Milling can be divided into various forms such as face milling, side milling, slotting, hole processing, etc.

CNC drilling

Drilling is a machining operation that creates circular holes on a workpiece. By using a rotating drill bit, the material is cut on the workpiece through high-speed rotation and feeding, achieving the machining of holes.

CNC turning

CNC turning is an operation used to process cylindrical workpieces. On a lathe, the workpiece rotates while the tool cuts on the workpiece. By adjusting the position and feed rate of the cutting tool, cylindrical machining of different shapes and sizes can be achieved.

CNC boring

CNC boring is an operation used to process holes. By rotating the cutting tool, material is cut on the workpiece to achieve hole expansion or improve machining accuracy.

cnc grinding

CNC grinding is an operation that uses grinding stones or wheels for cutting. Through grinding, precision machining of the workpiece surface and improvement of surface quality can be achieved.

CNC cutting

CNC cutting is an operation that divides a workpiece into the required dimensions. Through CNC cutting machines, plates, pipes, etc. can be cut to meet the needs of different shapes and sizes.

CNC processing equipment and its key components

numerical control machine

CNC machine tools are the main equipment for CNC machining. Composed of multiple key components, including the bed, spindle, feed system, servo drive system, tool library, etc.

CNC controller

The CNC controller is the core equipment for controlling and managing the operation of CNC machine tools. It consists of input devices (such as keyboards and mice), CNC system software, CNC host, and servo drivers. The CNC controller is responsible for loading and executing CNC programs, and controlling various axial and cutting parameters.

Axial system

The axial system is a key part of CNC machine tools, used to control the movement of workpieces and cutting tools. It includes different axes such as X-axis, Y-axis, Z-axis, etc. Each axis is composed of corresponding servo motors, slide rails, ball screws, encoders, etc.

principal axis

Spindle is the main cutting tool on CNC machine tools, used for rotating cutting tools. The spindle is usually composed of a motor, spindle head, tool clamping device, etc., providing rotational speed and cutting force.

Tools and tool magazine

The cutting tool is a crucial part of CNC machining, used for cutting and removing materials. The tool library is a device for storing and managing various tools, which can automatically select and replace tools to meet different processing needs.

fixture

The fixture is used to fix and position the workpiece, ensuring its stability and accuracy during the machining process. Fixtures can be mechanical fixtures, vacuum cup fixtures, pneumatic fixtures, etc., selected according to the shape of the workpiece and processing requirements.

Programming and control software

CNC machining requires the use of specific programming languages to write CNC programs. Programming software is used to create and edit CNC programs, while control software is used to control and monitor the operation of CNC machine tools.

What is a CNC machine tool

CNC machine tool refers to a machine tool that controls the movement and machining process of the machine tool through a computer control system. It introduces computer technology on the basis of traditional machine tools, and achieves automatic control of the machine tool through pre written CNC programs.

Advantages of CNC machine tools

High precision

 CNC machine tools achieve high-precision machining through precise calculations and motion control, ensuring product quality and dimensional accuracy.

High efficiency

CNC machine tools have the characteristics of automation, which can achieve automated processing through pre written CNC programs, improving production efficiency and processing speed.

Flexibility

CNC machine tools have strong flexibility in processing different shapes and sizes by writing different CNC programs according to different processing needs and requirements.

Types of CNC machine tools

CNC milling machine

used for milling operations, cutting materials on workpieces through rotating tools to achieve machining of planes, curved surfaces, and various shapes.

CNC lathe

used for turning operations, which cuts materials on the workpiece through the relative movement of rotating workpiece and cutting tool, achieving the processing of cylindrical and conical shapes.

CNC drilling machine: used for drilling operations, by rotating the drill bit to cut materials on the workpiece and achieve hole processing.

CNC grinding machine

used for grinding operations, cutting materials on workpieces through grinding stones or wheels to achieve high-precision machining and improve surface quality.

CNC boring machine

used for boring operations, which cuts materials on the workpiece by rotating the tool to achieve hole expansion and improve machining accuracy.

CNC shearing machine: used for cutting operations, cutting workpieces through cutting tools to achieve the segmentation of plates, pipes, etc.

Wire cutting machine

It uses electric discharge for cutting operations, processing materials with complex shapes and high hardness.

CNC machine tool programming

CNC machine tool programming refers to writing a CNC program that tells the CNC machine how to perform machining operations and control movements. CNC programming is a key technology that determines the machining accuracy, efficiency, and finished product quality of CNC machine tools.

Steps for programming CNC machine tools

Firstly, it is necessary to determine the cutting tools, cutting paths, and processing sequences required during the processing process based on the design requirements and processing technology of the product.

Select the appropriate programming language and environment based on the type of CNC machine tool and control system. Common CNC programming languages include G code, M code, ISO code, etc.

Use the selected programming language to write CNC programs. A CNC program is a collection of instructions used to describe the various steps and parameter settings during the machining process. These commands include tool path, feed rate, cutting depth, cutting direction, etc.

After completing the CNC program, conduct debugging and verification. Run the program in a simulated environment or actual machine tool to check whether the machining path, cutting parameters, and workpiece size meet expectations.

After completing the verification, upload the CNC program to the control system of the CNC machine tool. Control the movement and machining process of the machine tool by loading and executing programs through the operating interface of the control system.

Common Instructions

• G code: used to describe the motion control of machine tools, such as linear interpolation, circular interpolation, fast positioning, etc.
• M code: used to describe the auxiliary functions of the machine tool, such as spindle start/stop, tool replacement, coolant switch, etc.
• T code: used to select tools in the tool library.
• S code: used to set the speed of the spindle.
• F-code: used to set the feed rate.

CNC machine tool programming requires a deep understanding of machine operation and process flow, as well as good logical thinking and programming skills.