Contour milling with line segments in CNC Programming - Mini Project: Build & Apply

Contour milling with line segments

📖 Scenario: You are programming a CNC machine to mill a simple contour made of straight line segments. The contour is defined by points on a 2D plane. You want to create a program that generates the G-code commands to move the milling tool along these line segments.

🎯 Goal: Build a CNC program script that defines the contour points, sets a feed rate, generates the G-code commands to move along each line segment in order, and outputs the final G-code commands.

📋 What You'll Learn

Create a list of contour points with exact coordinates

Define a feed rate variable

Generate G-code commands to move the tool along each line segment between points

Print the final G-code commands

💡 Why This Matters

🌍 Real World

CNC programmers often need to convert geometric contours into G-code commands that machines understand to mill parts accurately.

💼 Career

Understanding how to automate G-code generation for contours is useful for CNC operators, manufacturing engineers, and automation specialists.

1

Define the contour points

Create a list called contour_points with these exact points as tuples: (0, 0), (10, 0), (10, 5), (0, 5).

CNC Programming

# Create the list contour_points with the given points
# Your code here

Hint

Use a Python list with tuples for each point.

2

Set the feed rate

Create a variable called feed_rate and set it to 1500.

CNC Programming

contour_points = [(0, 0), (10, 0), (10, 5), (0, 5)]
# Set the feed_rate variable to 1500
# Your code here

Hint

Just assign the number 1500 to feed_rate.

3

Generate G-code commands for contour milling

Create a list called gcode_commands. Use a for loop with variables start and end to iterate over pairs of consecutive points in contour_points. For each pair, append a string to gcode_commands in this format: f"G1 X{end[0]} Y{end[1]} F{feed_rate}".

CNC Programming

contour_points = [(0, 0), (10, 0), (10, 5), (0, 5)]
feed_rate = 1500
# Create gcode_commands list and fill it with G1 commands for each line segment
# Your code here

Hint

Use a for loop with index to access pairs of points and format the G-code string.

4

Print the G-code commands

Use a for loop to print each command in gcode_commands on its own line.

CNC Programming

contour_points = [(0, 0), (10, 0), (10, 5), (0, 5)]
feed_rate = 1500
gcode_commands = []
for i in range(len(contour_points) - 1):
    start = contour_points[i]
    end = contour_points[i + 1]
    gcode_commands.append(f"G1 X{end[0]} Y{end[1]} F{feed_rate}")
# Print each G-code command on its own line
# Your code here

Hint

Use a for loop to print each string in gcode_commands.