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Preventive Maintenance Schedules 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 Preventive Maintenance Schedules flashcards as text

  1. When performing a weekly PM on a CNC machining center, which coolant system check is most critical?

    Answer: Check coolant concentration using a refractometer

    Coolant concentration directly affects tool life and corrosion protection, and should be verified weekly with a refractometer.

  2. A CNC lathe PM schedule calls for checking the chuck jaw repeatability. What instrument is used for this task?

    Answer: Dial test indicator

    A dial test indicator measures runout and positional repeatability of chuck jaws during PM checks.

  3. Which lubricant type is typically specified for CNC ball screw assemblies during scheduled PM?

    Answer: Low-viscosity grease such as NLGI #2

    Ball screws require NLGI #2 grease applied in controlled amounts to prevent over-lubrication and contamination.

  4. During a monthly PM inspection, a technician finds the CNC machine's air pressure regulator is set at 85 PSI instead of the required 100 PSI. What is the most likely consequence if left uncorrected?

    Answer: Inadequate clamping force on pneumatic fixtures

    Insufficient air pressure reduces clamping force on pneumatic workholding, risking part movement during cutting.

  5. What is the purpose of checking the Z-axis counterbalance during a CNC vertical machining center PM?

    Answer: To ensure the spindle head is properly supported against gravity at rest

    The Z-axis counterbalance supports the spindle head weight so the Z-axis servo is not overloaded when the axis is stationary.

  6. A PM checklist requires inspecting the CNC control cabinet filters. How often are these filters typically cleaned or replaced?

    Answer: Monthly or per manufacturer specification based on environment

    Control cabinet air filters trap dust that can cause overheating; cleaning frequency depends on the shop environment but is generally monthly.

  7. During a PM procedure, the technician notices the machine tool way covers (telescoping steel covers) are dented and not sliding freely. What is the primary risk if this is ignored?

    Answer: Chips and coolant contaminating the linear guideways

    Damaged way covers allow chips and coolant to reach the linear guides, causing accelerated wear and premature failure.