The Ultimate CNC Programming Examples Library — 50 Real G-Code Programs for Milling, Drilling, Pocketing and Contour Machining

CNC programming examples are one of the most valuable learning resources for machinists and programmers. Instead of studying theory alone, real machining programs demonstrate how professional CNC programs are structured and executed on industrial machines.

Most CNC programmers learn by analyzing existing programs that show how tool movements, drilling cycles, contour operations, and machining strategies are implemented in real production environments.

This library presents practical CNC machining programs used for common manufacturing operations.

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SECTION 1 — BASIC MILLING PROGRAM
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This program mills a square profile.

%
O1001
G90 G17 G40 G49 G80
G54
T1 M06
S3000 M03
G00 G43 Z100 H01
G00 X0 Y0
G01 Z-5 F200
G01 X40
G01 Y40
G01 X0
G01 Y0
G00 Z100
M30

This program demonstrates basic contour milling.

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SECTION 2 — DRILLING PROGRAM
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Drilling cycles simplify repetitive hole machining.

%
O2001
G90 G17 G40 G49 G80
G54
T2 M06
S2500 M03
G00 G43 Z100 H02
G81 X20 Y20 Z-15 R2 F120
X40 Y20
X60 Y20
G80
M30

The G81 canned cycle drills multiple holes automatically.

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SECTION 3 — PECK DRILLING PROGRAM
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Peck drilling is used for deeper holes.

%
O2100
G90 G17
G54
T3 M06
S2000 M03
G00 G43 Z100 H03
G83 X30 Y30 Z-30 R2 Q5 F100
G80
M30

The Q value controls the incremental drilling depth.

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SECTION 4 — POCKET MACHINING PROGRAM
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Pocket machining removes material inside a defined boundary.

%
O3001
G90 G17
G54
T4 M06
S3500 M03
G00 G43 Z100 H04
G00 X0 Y0
G01 Z-3 F150
G01 X40
G01 Y40
G01 X0
G01 Y0
G00 Z100
M30

This example demonstrates simple pocket milling.

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SECTION 5 — CIRCULAR INTERPOLATION PROGRAM
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Circular machining uses G02 and G03 commands.

%
O4001
G90 G17
G54
T5 M06
S3200 M03
G00 G43 Z100 H05
G00 X20 Y20
G01 Z-5 F150
G02 X40 Y20 I10 J0 F200
G03 X20 Y20 I-10 J0
G00 Z100
M30

These commands generate circular toolpaths.

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SECTION 6 — TOOL CHANGE PROGRAM
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Programs often require multiple tools.

%
O5001
G90 G17
G54
T1 M06
S3000 M03
G00 G43 Z100 H01
G00 X0 Y0
G01 Z-2 F150
G00 Z100
T2 M06
G00 G43 Z100 H02
G01 X50 Y50
M30

The machine automatically changes tools during the program.

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SECTION 7 — SAFE PROGRAM STRUCTURE
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Professional CNC programs follow a structured pattern.

Program start

G90 G17 G40 G49 G80

Tool preparation

T1 M06
G43 H01

Machining operations

G01 G02 G03

Program end

M30

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FINAL PRINCIPLE

Studying real CNC programming examples is one of the fastest ways to learn CNC machining. By analyzing program structures, canned cycles, and machining patterns, CNC programmers can develop efficient machining strategies and create reliable programs for industrial CNC machines.