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CNC Mill Setup & Operation 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 CNC Mill Setup & Operation flashcards as text

  1. A CNC mill is producing chatter marks on the part surface. Which of the following is the LEAST likely cause?

    Answer: Using a new, sharp cutting tool

    A sharp, new tool is less likely to cause chatter than worn tools, poor clamping, excessive overhang, or a resonant spindle speed.

  2. When setting a work zero using an edge finder, why is it important to account for the edge finder's tip diameter?

    Answer: Because the spindle centerline is offset from the workpiece edge by the tip radius, which must be added or subtracted from the zero offset

    An edge finder tip is typically 0.200" diameter, so when it deflects on the edge, the spindle center is 0.100" away from the true workpiece edge — this offset must be applied to the zero position.

  3. What does the term 'chip load' mean in CNC milling?

    Answer: The amount of material removed per tooth per revolution, equivalent to feed per tooth

    Chip load (feed per tooth) = feed rate ÷ (RPM × number of flutes) and is the primary driver of cutting force per edge.

  4. Which of the following materials is best machined with a high spindle speed and moderate feed using an uncoated carbide end mill?

    Answer: 6061-T6 Aluminum

    Aluminum alloys like 6061 are soft and non-abrasive, allowing very high SFM values with sharp, uncoated carbide to prevent built-up edge.

  5. On a Fanuc control, what is the purpose of the RESET key during program execution?

    Answer: It stops program execution and returns the program cursor to the beginning

    Pressing RESET stops motion, cancels the current block, and resets the program pointer to the start, requiring a new Cycle Start to re-run.

  6. Which workholding method is most appropriate for CNC milling a thin, flat aluminum plate that cannot be clamped on the edges?

    Answer: Double-sided tape or a vacuum fixture

    Double-sided tape or a vacuum fixture holds the full underside of the plate without obstructing the top surface or bending thin material.

  7. What does the S-word specify in a CNC milling program block such as 'S2500 M03'?

    Answer: Spindle speed in revolutions per minute (RPM)

    S2500 sets the spindle speed to 2500 RPM; M03 simultaneously starts the spindle in the clockwise (forward) direction.