Practice Test Geeks(CNC) Computer Numerical Control Machinist Technical Practice Test
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Programming & Machine 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 Programming & Machine Operation flashcards as text

  1. What is the primary difference between a parametric macro program (custom macro) and a standard CNC program?

    Answer: Macro programs use variables and arithmetic logic to create flexible, reusable code

    Custom macros use variables (#1, #100, etc.) and logic (IF-GOTO, WHILE) to create programs that can adapt to different part sizes or repeat complex patterns.

  2. In Fanuc macro B programming, local variables are numbered in which range?

    Answer: #1–#33

    Local variables #1–#33 are cleared when a macro call ends, while #100–#199 are common variables that persist during program execution.

  3. A CNC machinist is running a long program and wants to skip a section of code during a test run. Which feature allows skipping blocks marked with a '/' character?

    Answer: Block delete (optional block skip)

    The Block Delete (optional block skip) feature, when activated on the control panel, causes the controller to skip any block beginning with a '/' (slash).

  4. What does 'dry run' mode do on a CNC machining center?

    Answer: Overrides programmed feed rates so all moves run at rapid traverse speed for verification

    Dry run overrides all programmed feed rates to rapid (or a set jog rate), allowing fast program verification without worrying about actual cutting speeds.

  5. When using the MDI (Manual Data Input) mode on a CNC control, what is the operator doing?

    Answer: Manually entering and executing single CNC blocks directly at the control

    MDI mode allows the operator to type and immediately execute individual CNC blocks for tasks like tool changes, spindle starts, or probing without loading a full program.

  6. A CNC operator notices the spindle is running but the axes are not moving during program execution. Which mode is most likely active?

    Answer: Machine lock (axis inhibit)

    Machine lock (axis inhibit) allows the program to run and the display to update, but prevents actual axis motion — useful for safe program verification.

  7. What is the purpose of using a 'proof cut' (or test cut) at reduced feed rate override before a full production run?

    Answer: To verify the program produces the correct part geometry and tool paths before running at full production rates

    A proof cut at reduced feed rate (e.g., 25–50% override) allows the operator to verify tool paths, offsets, and part geometry before committing to full-speed production.