Practice Test Geeks(CNC) Computer Numerical Control Machinist Technical Practice Test
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G-Code & M-Code Programming Flashcards

7 cards from real CNC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 G-Code & M-Code Programming flashcards as text

  1. Which G-code cancels cutter radius compensation?

    Answer: G40

    G40 cancels cutter radius compensation (left or right) that was previously activated.

  2. What does the address 'F' specify in a CNC program?

    Answer: Feed rate

    The F address defines the feed rate, typically in inches per minute (IPM) or millimeters per minute (mm/min).

  3. M06 is used to command which machine function?

    Answer: Tool change

    M06 initiates an automatic tool change on CNC machining centers.

  4. In G-code, what does G17 specify?

    Answer: XY plane selection

    G17 selects the XY plane, which is required for circular interpolation arcs in that plane.

  5. Which M-code turns the spindle on in the counter-clockwise direction?

    Answer: M04

    M04 starts the spindle rotating in the counter-clockwise (CCW) direction.

  6. What is the purpose of G91 in a CNC program?

    Answer: Incremental positioning mode

    G91 switches the control to incremental mode where all coordinates are relative to the current tool position.

  7. Which code in a CNC turning program specifies the spindle speed in surface feet per minute?

    Answer: G96

    G96 activates Constant Surface Speed (CSS) mode, where spindle RPM automatically adjusts to maintain a constant surface speed as diameter changes.