Practice Exam Questions And Correct

CNC Machine Operator Certification Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What does CNC stand for?
• Computer Numerical Control
• Computer Numeric Code
• Controlled Numerical Coding
• Coded Number Computation

Answer: A. Computer Numerical Control

Rationale: CNC stands for Computer Numerical Control, which refers

to computer-based systems that control machine tools.

• What is the main function of a CNC machine?
• To design parts
• To control machining tools automatically 1 / 3

• To inspect finished parts
• To assemble products

Rationale: CNC machines automatically control tools to perform

machining operations with precision.

3. The G-code command G00 represents:

• Circular interpolation
• Rapid positioning
• Feed motion
• Dwell command

Rationale: G00 is used for rapid positioning of the tool without

cutting.

4. The G-code G01 stands for:

• Dwell
• Thread cutting
• Linear interpolation (cutting feed motion)
• Machine stop

Rationale: G01 is used for linear interpolation or straight-line cutting

at a programmed feed rate.

• Which of the following is a common coordinate system used in CNC

machines?

• Polar coordinates
• Cylindrical coordinates
• Cartesian coordinates 2 / 3

• Spherical coordinates

Rationale: CNC machines primarily use the Cartesian coordinate

system (X, Y, Z axes).

• What does M03 command do in CNC programming?
• Stops the spindle
• Starts the spindle in a clockwise rotation
• Starts spindle counterclockwise
• Turns off coolant

Rationale: M03 activates the spindle in the clockwise direction.

• Which axis represents depth in milling operations?
• X
• Y
• Z
• A

Rationale: The Z-axis typically represents the vertical movement,

controlling depth of cut.

• A CNC lathe primarily controls which two axes?
• X and Z
• X and Z
• Y and Z
• X and Y

Rationale: CNC lathes operate on X (diameter) and Z (length) axes.

• / 3