What is CNC machining in CNC Programming - Visual Explanation

Concept Flow - What is CNC machining

Design Created

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Program Written

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Program Loaded into CNC Machine

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Machine Reads Instructions

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Machine Moves Tools

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Material is Cut/Shaped

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Finished Part Produced

CNC machining starts with a design, then a program is made and loaded into the machine. The machine reads the program and moves tools to cut or shape material, producing the final part.

Execution Sample

CNC Programming

G01 X10 Y10 F100
G01 X20 Y10
G01 X20 Y20
G01 X10 Y20
G01 X10 Y10

This CNC program moves the tool in a square path starting at (10,10) with a feed rate of 100.

Execution Table

Step	Command	Action	Tool Position	Feed Rate	Output
1	G01 X10 Y10 F100	Move tool to X=10, Y=10	(10,10)	100	Tool moves to start point
2	G01 X20 Y10	Move tool to X=20, Y=10	(20,10)	100	Tool moves right
3	G01 X20 Y20	Move tool to X=20, Y=20	(20,20)	100	Tool moves up
4	G01 X10 Y20	Move tool to X=10, Y=20	(10,20)	100	Tool moves left
5	G01 X10 Y10	Move tool to X=10, Y=10	(10,10)	100	Tool moves down, square complete

💡 All commands executed, tool returned to start, square path complete

Variable Tracker

Variable	Start	After 1	After 2	After 3	After 4	After 5
Tool Position	(0,0)	(10,10)	(20,10)	(20,20)	(10,20)	(10,10)
Feed Rate	N/A	100	100	100	100	100

Key Moments - 3 Insights

Why does the tool position change after each command?

Each G01 command tells the machine to move the tool to a new coordinate, so the tool position updates step-by-step as shown in the execution_table.

What does the feed rate number mean and why does it stay the same?

Feed rate is the speed at which the tool moves. It is set once in the first command and remains the same unless changed, as seen in the variable_tracker.

Why does the tool return to the starting point at the end?

The last command moves the tool back to the start to complete the square shape, ensuring the path is closed as shown in the last row of the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the tool position after step 3?

A (10,20)

B (20,20)

C (20,10)

D (10,10)

💡 Hint

Check the 'Tool Position' column in row 3 of the execution_table.

At which step does the feed rate get set to 100?

A Step 2

B Step 5

C Step 1

D Feed rate is never set

💡 Hint

Look at the 'Feed Rate' column in the execution_table and variable_tracker for when it first changes.

If the last command was removed, what would happen to the tool position?

A It would stay at (10,20)

B It would move to (10,10)

C It would move to (20,20)

D It would return to (0,0)

💡 Hint

Check the tool position after step 4 in the execution_table and variable_tracker.

Concept Snapshot

CNC machining uses a program to control machine tools.
Commands move the tool to specific coordinates.
Feed rate controls tool speed.
The machine follows commands step-by-step.
This shapes material into the desired part.

Full Transcript

CNC machining means using a computer program to control a machine that cuts or shapes material. The process starts with a design, then a program is written with commands telling the machine where to move the tool and how fast. The machine reads these commands one by one, moving the tool to the right spots and cutting the material. For example, a simple program moves the tool in a square path by changing its X and Y positions. The feed rate sets how fast the tool moves and stays the same unless changed. At the end, the tool returns to the starting point to finish the shape. This step-by-step control lets us make precise parts easily.