G-code program structure in CNC Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the O number at the start of a G-code program?

The O number is the program number or ID. It helps the CNC machine identify and select the program to run, like a name tag for the program.

beginner

What does the G00 command do in a G-code program?

G00 tells the machine to move the tool quickly to a new position without cutting. Think of it as moving your hand fast to a new spot before starting to draw.

beginner

Why is it important to have a M30 command at the end of a G-code program?

M30 signals the end of the program and resets the machine to the start. It’s like saying "I’m done" so the machine knows to stop and get ready for the next job.

intermediate

What role do G-codes and M-codes play in a G-code program?

G-codes control the tool’s movements and actions (like moving, cutting), while M-codes control machine functions (like turning the spindle on/off). Together, they tell the machine what to do step-by-step.

intermediate

Explain the typical structure order of a simple G-code program.

A simple G-code program usually starts with the program number (O), then setup commands (like tool selection and spindle on), followed by motion commands (G00, G01), and ends with the program stop command (M30).

What does the O1000 line represent in a G-code program?

A Tool number

B Program number or ID

C Spindle speed

D Feed rate

The O number is the program ID used to identify the program.

Which command moves the tool quickly without cutting?

A G01

B M30

C G00

D M03

G00 is the rapid positioning command for fast moves without cutting.

What does the M30 command do?

A Starts the spindle

B Changes tool

C Moves tool to home

D Ends the program and resets

M30 ends the program and resets the machine for the next run.

Which codes control machine functions like spindle on/off?

A M-codes

B G-codes

C T-codes

D F-codes

M-codes control machine functions such as spindle and coolant.

What is the correct order in a simple G-code program?

A Program number, setup commands, motion commands, end command

B End command, motion commands, setup commands

C Motion commands, program number, end command

D Setup commands, end command, program number

A typical program starts with the program number, then setup, motion, and ends with the stop command.

Describe the main parts of a G-code program and their purpose.

Think about how the program starts, what it does, and how it finishes.

Explain the difference between G-codes and M-codes in a G-code program.

One controls motion, the other controls machine actions.