CNC program documentation in CNC Programming

Introduction

Writing notes inside a CNC program helps you and others understand what the program does. It makes fixing and changing the program easier.

When creating a new CNC program to explain each step.

When sharing a program with a teammate or operator.

When saving a program for future use or updates.

When troubleshooting problems in the machining process.

When documenting special instructions or safety warnings.

Syntax

CNC Programming

(In most CNC languages, comments are written using parentheses or semicolons)

( This is a comment )
; This is also a comment

Comments do not affect how the machine runs the program.

Use comments to explain complex moves or tool changes.

Examples

This comment explains the purpose of the program section.

CNC Programming

(Start of program - drilling holes)

This comment shows a tool change step.

CNC Programming

; Tool change to drill bit

This comment describes the move command that follows.

CNC Programming

(Move to X10 Y20 Z5 - safe position)

Sample Program

This program drills three holes in a row. Comments explain each step so anyone reading the program knows what is happening.

CNC Programming

(Program to drill 3 holes)

G21 (Set units to millimeters)
G90 (Use absolute positioning)

(Tool change to drill bit)
T1 M06

(Drill first hole at X10 Y10)
G00 X10 Y10 Z5 (Move above hole)
G01 Z-5 F100 (Drill down)
G00 Z5 (Retract)

(Drill second hole at X20 Y10)
G00 X20 Y10 Z5
G01 Z-5 F100
G00 Z5

(Drill third hole at X30 Y10)
G00 X30 Y10 Z5
G01 Z-5 F100
G00 Z5

M30 (End of program)

Important Notes

Always keep comments clear and short.

Update comments if you change the program.

Use comments to mark important sections or warnings.

Summary

Comments help explain CNC programs for easier understanding.

Use parentheses or semicolons to write comments.

Good documentation saves time and prevents mistakes.