Manufacturing Processes-II Lab
Experiment 03
CNC Milling
Objectives:
• To write the G & M codes for profile milling operations and perform the
operations on the CNC Milling.
Types of CNC machines
• CNC Turning
• CNC milling
• CNC wirecut
• CNC router
• CNC laser cut
• CNC water jet cutting etc.
Working on CNC Machine/ EDM wirecut
C) Machine
A) Instructions B) Controller
Component
A) Instructions to machine: (based on the available facilities in Labs)
Machine Form of instruction
EDM wirecut 2D cad drawings using AutoCAD software
CNC lathe Writing G & M codes manually
CNC milling Generating G & M codes using Fusion 360 software
G & M codes
Generally, G-codes create movement & M-codes turn things ON, turn things OFF.
Recommended order of Addresses in a block
N… G… X (or U)… Z (or W)… F… S… T… D… M… H…
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Department of Mechanical Engineering, Air University A&AC Kamra
Manufacturing Processes-II Lab
Addresses
N Refers to block number / sequence
G G-codes
X Absolute distance traveled by tool in x-axis
U Incremental distance traveled by tool in x-axis
Z Absolute distance traveled by tool in z-axis
W Incremental distance traveled by tool in z-axis
F Feed rate
S Spindle speed
T Tooling management
M M-codes
G-codes (Preparatory functions)
G
Code Description
G00 Positioning (rapid traverse)
G01 Linear interpolation
G02 Circular interpolation clockwise
G03 Circular interpolation counterclockwise
G04 Dwell
G17 Plane XY
G18 Plane XZ
G19 Plane YZ
G20 Dimensions in inches
G21 Dimensions in mm
G28 Automatic machine reference
G40 Cancel cutter radius compensation
G41 Cutter radius compensation left
G42 Cutter radius compensation right
G80 Deselection of drilling cycles
G90 Absolute programming
G91 Incremental programming
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Department of Mechanical Engineering, Air University A&AC Kamra
Manufacturing Processes-II Lab
G92 Spindle speed limit
G98 Feed per minute
G99 Feed per revolution
G96 Constant cutting speed, feed per revolution
G97 Constant spindle speed
M-codes (Miscellaneous functions)
M
Code Description
M00 Programmed stop
M01 Optional stop
M02 Main program end
M03 Spindle rotation clockwise
M04 Spindle rotation counterclockwise
M05 Spindle stop
M06 Tool change
M08 Coolant ON
M09 Coolant OFF
M10 Chuck open
M11 Chuck close
M19 Spindle lock
M20 Spindle unlocks
M30 Main program end
Procedure:
• Mount the Workpiece: Securely clamp the workpiece onto the CNC machine's
table, ensuring it is stable to prevent movement during the machining operation.
• Tool Selection: Insert Tool 1 into the machine's spindle, which is appropriate for
the profile milling operation (e.g., an end mill). Work Coordinate System: Use
the command G54 to select the correct work coordinate system.
• Zeroing: Zero the machine at the starting point of the workpiece (X0, Y0, Z0)
using absolute positioning (G90). Tool Offset: Apply tool offset with T1 D1 to
ensure proper tool length and diameter compensation.
• Feed Rate: Set the feed per revolution using G95 and assign the feed rate as
**0.9* (F0.9). Spindle Speed: Start the spindle in a clockwise direction at 1000
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Department of Mechanical Engineering, Air University A&AC Kamra
Manufacturing Processes-II Lab
RPM with M03 S1000.Move to Start Point: Use G00 X0 Y0 to move the tool
rapidly to the starting point in the XY plane
• Safe Z Position: Move the tool to a safe height using G00 Z10 to avoid collisions
while moving to the start position.
• Start Cutting: Begin the profile milling by lowering the tool to the cut depth with
G01 Z6.
• Perform a linear move from (X0, Y0) to (X-10, Y5), shaping part of the profile.
• Continue moving linearly along the Y-axis to Y41 to complete the side profile.
• Execute a circular interpolation with G02 to form an arc, moving to (X50, Y20)
with a radius of 30.
• Final Linear Move: Make a final linear move along the Y-axis to Y6 to finish the
remaining part of the profile.
• Retract Tool: Use G00 Z20 to raise the tool back to a safe Z height at Z20 after
the milling operation is complete.
• End the Program: Use M30 to stop the spindle and end the program.
Conclusion:
The CNC program above performs a profile milling operation on the workpiece,
creating a specific external contour. The tool follows both linear and circular paths to
achieve the desired profile. The procedure ensures that the tool moves rapidly to the
start position, avoiding any material collisions. The cutting operation is performed with
both linear and circular interpolation commands, forming both straight edges and
curves on the workpiece. Safe Z movements ensure the tool retracts properly between
operations. The program concludes with a spindle stop and machine readiness for the
next operation.
Photograph of the product/part manufactured in Lab:
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Department of Mechanical Engineering, Air University A&AC Kamra
