G-code Overview and Related Resources for Machinists

July 31, 2020 12:21 pm

G-code, or preparatory code, is the most widely used computer numerical control (CNC) programming language. It allows CNC programmers to give directions to the machine tool with specific paths that transform a design into a solid object.

In this article, we’ll take a look at the origins of this language, give a brief overview of its functions, and provide some recommended resources that will bolster your comprehension of G-code.

History of G-code in a nutshell

In the late 1950s, MIT’s Servomechanisms Laboratory was the first to successfully implement a numerical control programming language. By the 1970s, FANUC and Siemens both pushed for the code to be standardized in manufacturing as a predominant issue was the inconsistency of the programming language and machine tool capability. Later that decade, 3D Computer Aided Design/Computer Aided Machining (CAD/CAM) systems – which optimized the manufacturing process due to their ability to decrease material waste, improve turnaround times and provide clear visual concepts – hit the market and by the late 80s, became the standard for use in CNC machining applications.

These computer aided systems enable the articulation of a design into G-code. Fast forward to present day, G-code continues to be developed and implemented in new ways in the metalworking industry.

G-code Overview

Another accepted name for G-code is “preparatory code” which is just any CNC program that begins with the letter G. Overall, G-code is an action for the machine tool to perform. Some examples of G-code activated movements are:

  • Rapid transport of tool
  • Feed movements that result in a bored hole, a workpiece routed to specific dimension or a contour added to the edge of a workpiece
  • Controlled feed in a straight line or arc
  • Tool information like offset
  • Switch coordinate systems

Thought the letter G has come to represent the entire computer language, there are many other letters used within the G-code premise.

In addition to using our G-code YouTube series (in collaboration with Marc Cronin the G-Code Tutor) as a resource, here are a list of books to consider.

Recommended Books

CNC Lathe G-code & M-code Illustrative Handbook

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Are you looking for a practical resource to better understand G and M codes specifically for CNC lathe programming? Codes in this book have been arranged in a logical way based on number, name and group number. Each section contains a quick description of the code, the command format, notes and some examples.

CNC Programming: Beginning Basics of G-code

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This book is great for beginners as it explains G-code programming through topics such as Cartesian Coordinate systems and G & M code definitions. This text also has tutorials for milling applications along with tutorials for lathe applications with included code and explanation.

CNC Programming Handbook, Third Edition (Volume 1)

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Basic Programming Essentials: Learn Basic Batch, HTML, C-, and G- and M-code for CNC Milling Applications

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If you are someone who is looking for an introduction to programming, this is a good door opener before you take a dive deeper into G-code. More of an elementary option, but a good way for someone who is looking to become more comfortable with the subject.

 

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