Practice Test GeeksCNC - Cutting Practice Test
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Basics 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.

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  1. What is the role of a 'tool length offset' (TLO) in CNC machining?

    Answer: It compensates for the difference in length between tools so Z-axis moves are accurate

    Tool length offsets tell the controller the actual length of each tool so Z coordinates programmed relative to the workpiece surface remain accurate regardless of which tool is active.

  2. Which cutting parameter should be reduced FIRST when machining a thin-walled workpiece to prevent deflection?

    Answer: Radial depth of cut (stepover)

    Reducing radial depth of cut lowers the lateral cutting force that causes thin walls to flex or chatter.

  3. What does the CNC term 'dry run' mean?

    Answer: Executing the program at reduced feed with no workpiece installed to verify motion

    A dry run cycles the program at reduced or rapid speed with the workpiece absent to verify the tool path and prevent crashes before actual cutting.

  4. When is conventional (up) milling preferred over climb milling?

    Answer: When machining hard, abrasive materials with no backlash in the machine

    Conventional milling is preferred on machines with leadscrew backlash or when cutting hard, abrasive materials where climb milling's tendency to 'grab' could damage the setup.

  5. What is the purpose of a 'canned cycle' (e.g., G81, G83) in CNC programming?

    Answer: To simplify repetitive operations like drilling with a single-block command

    Canned cycles condense multi-step operations (rapid approach, feed, retract) into one G-code block, greatly reducing program length for drilling, boring, and tapping.

  6. What effect does increasing the number of flutes on an end mill have when machining aluminum?

    Answer: Chip evacuation can worsen because flute gullets become smaller

    Aluminum produces large, stringy chips; more flutes mean shallower gullets that can pack and clog, which is why 2- or 3-flute end mills are standard for aluminum.

  7. What does the G28 command do on most CNC machining centers?

    Answer: Returns all axes to the machine reference (home) position

    G28 commands the machine to rapid all specified axes through an intermediate point and then to the machine home (reference) position.