Comprehending CNC Motion Control and Three Common Types
Knowledge

Comprehending CNC Motion Control and Three Common Types

The primary advantage provided by various types of CNC machine tools is enhanced automation, as it allows for the reduction or elimination of operator intervention in the production of workpieces.
Published: Nov 17, 2023
Comprehending CNC Motion Control and Three Common Types

The advantage of many CNC machines is their ability to operate unattended throughout the entire machining cycle, providing the operator with the freedom to engage in other tasks. This not only reduces operator fatigue but also minimizes errors resulting from operational mistakes. Additionally, it ensures a consistent and predictable machining time for each workpiece. As the machine operates under program control, the skill level required of the CNC operator is lower compared to a machinist using conventional machine tools.

At the core of CNC functionality lies motion control—a fundamental and essential aspect. All types of CNC equipment feature two or more axes for precise and automatic positioning along their respective lengths of travel. Unlike conventional machines that rely on manual cranks and handwheels for motion, CNC machines utilize servomotors controlled by the CNC and guided by the part program. This allows for programmable motion types, such as rapid, linear, and circular, specifying the axes to move, the extent of motion, and the feed rate, in almost all CNC machine tools.

The execution of a CNC command involves the control system instructing the drive motor through a program to rotate a precise number of times. The rotation of the drive motor, in turn, moves the ballscrew, which drives the linear axis. A feedback device at the opposite end of the ballscrew confirms the completion of the commanded rotations, ensuring precision.

While a simple analogy to a table vise's linear motion helps illustrate the concept, the precision of a CNC machine's linear axis is far superior. The number of revolutions of the axis drive motor precisely dictates the amount of linear motion along the axis.

Understanding the programmable motion directions (axes) is crucial for CNC programmers. The axis names vary between machine tool types and are denoted by letter addresses, with common names like X, Y, Z, U, V, and W for linear axes, and A, B, and C for rotary axes. Programs consist of commands, and commands consist of words, each with a letter address and a numerical value. CNC control manufacturers may differ in how they determine word names, requiring reference to the manufacturer's programming manual for clarity.

A brief list of some common word types includes:

  • O: Program number (used for program identification)
  • N: Sequence number (used for line identification)
  • G: Preparatory function
  • X, Y, Z: Linear axis designations
  • R: Radius designation
  • F: Feedrate designation
  • S: Spindle speed designation
  • H: Tool length offset designation
  • D: Tool radius offset designation
  • T: Tool designation
  • M: Miscellaneous function

Rotary axis departures also require a letter address (usually A, B, or C) along with the endpoint specified in degrees.

The three most basic motion types in CNC machines are:

Rapid Motion (Positioning): Used to command the machine's fastest possible rate, minimizing non-productive time during the machining cycle. Common applications include positioning the tool to and from cutting positions, moving to clear clamps and obstructions, and any non-cutting motion during the program.

Straight Line Motion: Enables the programmer to command perfectly straight line movements, as discussed in linear interpolation. This motion type allows the specification of the motion rate (feed rate) during the movement and can be employed for straight cutting movements, such as drilling, turning straight diameters, faces or tapers, and milling straight surfaces.

Circular Motion: Causes the machine to move in a circular path, generating radii during machining. This motion type, discussed in circular interpolation, maintains feed rate considerations made in straight-line motion.

Published by Nov 17, 2023 Source: mmsonline Source: mmsonline Source: mmsonline

Further reading

You might also be interested in ...

Headline
Knowledge
Precision in Rotation: Indexing Plates in Metal Machining
Rotary Indexing Plates are precision components of milling machines that facilitate the precise angular positioning of workpieces and cutting tools. They are used in both metal machining and woodworking, and while they share a fundamental purpose, there are notable differences in their design, capabilities, and applications due to the distinct characteristics of the materials and processes involved.
Headline
Knowledge
Sheet Metal Fabrication Machines: An Overview
Sheet metal machines are widely used in various manufacturing industries for shaping, cutting, and forming sheet metal into different components. Some of the industries that extensively utilize sheet metal machines include light industries such as electrical and medical equipment, all the way up to heavy industries such as automotive, rail, oil and gas, as well as wind power generation.
Headline
Knowledge
The Significance of Planing Machines in the Machining Tool Industry
Metal and wood planing machines are essential tools in the machining industry. Wood planers use a rotating cutterhead equipped with sharp blades to smooth and size workpieces, ensuring uniformity in woodworking projects. Metal planers use a cutting tool mounted on a reciprocating tool head to remove excess material from metal surfaces, achieving precise dimensions in components. Both types of planning machines enhance efficiency, precision, and the overall quality of finished products. Understanding the key features of the various types of planing machines will help you choose the right machine best suited for your machining needs.
Headline
Knowledge
Stamp Press Technology and Manufacturing in Taiwan
Nestled in the heart of East Asia, Taiwan has emerged as a powerhouse in the global stamp press industry, with a robust manufacturing ecosystem, and cutting-edge technology. With a rich manufacturing tradition and a focus on precision engineering, Taiwanese companies meet the demands of diverse sectors, ranging from electronics and automotive to medical devices and aerospace, supplying high-quality stamp press solutions to a diverse range of markets worldwide.
Headline
Knowledge
Introduction to Stamp Press Technology
Stamp press technology, also known as stamping or pressing, is a manufacturing process that utilizes a press to shape or cut materials into desired forms. This process involves the use of a die and a punch to form or cut the material, creating intricate shapes with high precision. Widely employed for mass production due to its speed, accuracy, and repeatability, this process is a crucial part of modern manufacturing.
Headline
Knowledge
Mechanical Reducers in Industrial Manufacturing
Speed reducers are powerful mechanical devices generally used in machining tools to multiply the force or torque generated by an input power source, thereby increasing the usable force, enhancing the performance and precision of the machining tool. They are also used in material handling systems such as conveyor belts and lifting mechanisms to control the speed of material transfer and manage heavy loads efficiently. By multiplying the available output force, they enable the use of a reduced input power source, resulting in cost savings for machine tool investments. When choosing the appropriate speed reducer, the torque, speed, and horsepower of the input, as well as the mounting configuration, efficiency, and required lifetime all need to be considered. The quality of the machine chosen will also be reflected in the amount of backlash, transmission error, torsional rigidity, and inertia experienced during machining.
Headline
Knowledge
Introduction to Stamp Press Technology
Stamp press technology, also known as stamping or pressing, is a manufacturing process that utilizes a press to shape or cut materials into desired forms. This process involves the use of a die and a punch to form or cut the material, creating intricate shapes with high precision. Widely employed for mass production due to its speed, accuracy, and repeatability, this process is a crucial part of modern manufacturing.
Headline
Knowledge
Innovations in Sawing Technology
The traditional image of saws as just cutting tools is being reshaped by cutting-edge advancements that integrate automation and robotics in sawing technologies, paving the way for greater precision and efficiency of sawing technology in manufacturing.
Headline
Knowledge
The Fundamentals of Drilling Machines
Drilling machines play a pivotal role in the manufacturing industry, using rotary motion to create precise holes in a variety of materials. Whether it's metal, wood, plastic, or composites, drilling machines are versatile and essential for producing components in countless applications.
Headline
Knowledge
Hybrid Milling in Manufacturing: Integrating Additive and Subtractive Processes
The integration of additive manufacturing (AM) and subtractive milling processes has emerged as a transformative manufacturing process known as hybrid milling. This technique combines the strengths of both 3D printing and traditional subtractive milling, opening up new possibilities and diverse applications for creating complex geometries with improved material efficiency.
Headline
Knowledge
Features and Mechanics of Industrial Saws
Industrial saws shape raw materials into precise components that form the backbone of countless products. Understanding the mechanics of sawing, examining the fundamental principles, cutting mechanisms, and essential aspects of safety and maintenance will ensure the most efficient and safe operation of industrial saws.
Headline
Knowledge
Understanding the Diversity of Industrial Saws
Industrial saws play a pivotal role in processing a wide range of materials with precision and efficiency. Taiwan is a major supplier of industrial saws to the automotive, aerospace, and construction, as well as the metal fabrication industries. This article aims to provide a comprehensive understanding of the diverse industry of industrial saws, exploring their types, structures, applications, and the crucial role they play in various industries.
Agree