CNC CNC G-Code and Programming 1 — Questions and Answers
Question 1: Which G-code command is used to set absolute positioning mode in CNC programming?
- G90 (Correct answer)
- G91
- G92
- G93
Correct answer: G90
G90 sets the machine to absolute positioning mode, where all coordinates are measured from the work origin.
Question 2: What does the M03 command do in a CNC cutting program?
- Stops the spindle
- Starts the spindle clockwise (Correct answer)
- Starts the spindle counterclockwise
- Activates coolant
Correct answer: Starts the spindle clockwise
M03 starts the spindle in the clockwise (CW) direction, which is the standard direction for most cutting tools.
Question 3: Which G-code is used to perform a circular interpolation in the clockwise direction?
- G00
- G01
- G02 (Correct answer)
- G03
Correct answer: G02
G02 commands the machine to move in a clockwise circular arc, defined by the center point (I, J, K) or radius (R).
Question 4: What is the function of the F-word in a CNC program block?
- Spindle speed
- Feed rate (Correct answer)
- Tool number
- Fixture offset
Correct answer: Feed rate
The F-word specifies the feed rate, which controls how fast the cutting tool moves through the material.
Question 5: Which G-code command cancels tool radius compensation in CNC programming?
- G40 (Correct answer)
- G41
- G42
- G43
Correct answer: G40
G40 cancels cutter radius compensation, returning the tool path to the programmed centerline.
Question 6: In a CNC program, what does the S-word specify?
- Step-over distance
- Surface finish code
- Spindle speed in RPM (Correct answer)
- Subroutine number
Correct answer: Spindle speed in RPM
The S-word defines the spindle speed in revolutions per minute (RPM), which directly affects cutting performance.
CNC CNC G-Code and Programming 1
Which G-code command is used to set absolute positioning mode in CNC programming?