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Coordinate Systems & Datum Setup 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 Coordinate Systems & Datum Setup flashcards as text

  1. What does the G54 code specify in a CNC program?

    Answer: The first work coordinate system offset

    G54 activates the first work coordinate system (WCS) offset, shifting the program origin to a user-defined location on the workpiece.

  2. What is a 'work offset' in CNC machining?

    Answer: The distance between machine zero and the workpiece origin

    A work offset defines the distance from the machine's home/reference position to the desired program zero point on the workpiece.

  3. What is the primary function of a tool length offset (TLO) in CNC milling?

    Answer: To account for differences in tool length so Z-axis positions remain accurate

    Tool length offsets compensate for differences in tool length so that the programmed Z-axis positions correspond correctly to the actual tool tip location.

  4. When a machinist uses an edge finder to locate the edge of a workpiece, what must they account for when setting the work offset?

    Answer: Half the diameter of the edge finder stylus

    The edge finder registers the part edge at its centerline, so the machinist must offset by half the stylus diameter to find the true edge position.

  5. In CNC programming, what does the G28 command instruct the machine to do?

    Answer: Return to machine home (reference) position

    G28 commands the machine to return to its machine home (reference zero) position, typically passing through an intermediate point for safety.

  6. Machine Zero (machine home or reference point) is best described as:

    Answer: A fixed reference point established by limit switches or encoders on the machine

    Machine zero is a fixed reference position on the CNC machine determined by homing switches or encoders, from which all other coordinate systems are measured.

  7. Which of the following best describes 'program zero' in CNC machining?

    Answer: The user-defined origin point for a specific workpiece or setup

    Program zero is the origin point defined by the programmer, typically set at a convenient feature on the workpiece such as a corner or centerline.