In this lesson, I’ll introduce you to G code, which is the most common way to program CNC machines. Watch the video below, and check out all the extra resources on this page!
Lesson Summary
Here’s the lesson in a nutshell.
The machine is given positions by using the Cartesian coordinate system. This can define any point in 3D space.
The origin is the X, Y and Z “zero” point that we program from. It’s usually based on where the part is within the machine.
A modal command is a code that stays active until it’s either turned off or overwritten. It works in the same way that a light switch does.
A non-modal command is a single-use command that does not stay active. It’s more like a button on a keyboard.
G codes are preparatory codes, and they get the machine ready to perform some kind of action.
M codes are miscellaneous commands, and they can be used for pretty much anything.
Positional addresses give the machine a position to interpret in some way, whether to use as a reference position or a go-to point.
“Other” letter addresses are used to set parameters and values, and they’re paired with G and M codes.
Review Questions
- What’s an example of a modal command?
- Give an example of a non-modal command.
- What system is used to define positions within the machine?
- What are M codes used for?
- What are G codes used for?
- Name 3 types of positional addresses along with what they define.