Contour milling with line segments in CNC Programming

Introduction

Contour milling with line segments helps cut shapes by moving the tool along straight lines. It is simple and precise for making edges and outlines.

Cutting a rectangular pocket in a metal plate.

Tracing the outline of a part with straight edges.

Removing material along a straight path on a flat surface.

Creating a frame or border with straight sides.

Machining a simple polygon shape with straight edges.

Syntax

CNC Programming

G01 Xx Yy Ff

G01 means move in a straight line at a controlled feed rate.

Xx and Yy specify the end point coordinates of the line segment.

Ff sets the speed of the tool movement.

Examples

Move the tool in a straight line to X=10, Y=0 at feed rate 100.

CNC Programming

G01 X10 Y0 F100

Move diagonally to X=10, Y=10 at feed rate 150.

CNC Programming

G01 X10 Y10 F150

Move straight to X=0, Y=10 using the last feed rate set.

CNC Programming

G01 X0 Y10

Sample Program

This program mills a rectangular contour 50mm wide and 30mm tall by moving the tool along four straight line segments.

CNC Programming

G21 ; Set units to millimeters
G90 ; Use absolute positioning
G00 X0 Y0 ; Move quickly to start point
G01 X50 Y0 F200 ; Cut line to X=50, Y=0
G01 X50 Y30 ; Cut line to X=50, Y=30
G01 X0 Y30 ; Cut line to X=0, Y=30
G01 X0 Y0 ; Cut line back to start
M30 ; End program

Important Notes

Always set the correct units (G20 for inches, G21 for millimeters) before contour milling.

Use absolute positioning (G90) to make coordinates easier to understand.

Feed rate (F) controls how fast the tool moves; too fast can damage the tool or part.

Summary

Contour milling with line segments uses straight moves (G01) to cut shapes.

Coordinates specify where the tool moves next.

Set units and positioning mode before starting the contour.