Tool length offset (G43) in CNC Programming - Mini Project: Build & Apply

Tool Length Offset (G43) in CNC Programming

📖 Scenario: You are programming a CNC milling machine to drill holes at different depths. To ensure the tool length is correctly compensated, you need to use the tool length offset command G43. This helps the machine know the exact length of the tool attached, so it drills at the right depth without crashing.

🎯 Goal: Build a simple CNC program that sets up a tool length offset using G43 and drills two holes at specified coordinates with correct depth compensation.

📋 What You'll Learn

Create a variable called tool_number with the value 1.

Create a variable called tool_length_offset with the value 10.5 (in millimeters).

Write a line of code that uses G43 with the tool_length_offset value and tool_number to apply the tool length offset.

Write two lines of code to drill holes at coordinates X50 Y50 and X100 Y50 with a depth of Z-20.

Print the complete CNC program lines as output.

💡 Why This Matters

🌍 Real World

Tool length offsets are essential in CNC machining to ensure the tool tip reaches the correct depth, preventing damage and ensuring precision.

💼 Career

CNC programmers and machinists use G43 commands daily to compensate for different tool lengths when changing tools on milling machines.

1

Set up tool number variable

Create a variable called tool_number and set it to 1.

CNC Programming

# Your code here

Hint

Use simple assignment like tool_number = 1.

2

Set up tool length offset variable

Create a variable called tool_length_offset and set it to 10.5 (millimeters).

CNC Programming

tool_number = 1
# Your code here

Hint

Assign the value 10.5 to tool_length_offset.

3

Write G43 command with tool length offset

Write a line of code that creates a string called g43_command with the value G43 H{tool_number} Z{tool_length_offset} using f-string formatting.

CNC Programming

tool_number = 1
tool_length_offset = 10.5
# Your code here

Hint

Use an f-string like f"G43 H{tool_number} Z{tool_length_offset}".

4

Create drilling commands and print full CNC program

Create two strings called drill1 and drill2 with values G01 X50 Y50 Z-20 and G01 X100 Y50 Z-20 respectively. Then print g43_command, drill1, and drill2 each on a new line.

CNC Programming

tool_number = 1
tool_length_offset = 10.5
g43_command = f"G43 H{tool_number} Z{tool_length_offset}"
# Your code here

Hint

Print each command on its own line using separate print() calls.