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Cutting Tool Geometry & Selection 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 Cutting Tool Geometry & Selection flashcards as text

  1. What does the ISO tolerance class 'M' mean in an insert designation code?

    Answer: The insert has a standard tolerance on the inscribed circle and thickness

    In the ISO insert code, tolerance class 'M' specifies a particular range of dimensional tolerances for the inscribed circle diameter and insert thickness.

  2. A thread milling cutter is preferred over a tap for which scenario?

    Answer: Threading thin-walled or large-diameter holes where tap breakage risk is high

    Thread milling is safer in large or thin-walled features because the small cutter cannot break catastrophically inside the part like a large tap can.

  3. Which drill geometry feature is designed to reduce thrust force during drilling?

    Answer: Web thinning (point thinning)

    Web thinning reduces the chisel edge width at the drill point, which significantly lowers the axial thrust force needed to penetrate the material.

  4. In CNC milling, 'climb milling' differs from 'conventional milling' primarily in:

    Answer: Whether chip thickness decreases or increases from entry to exit

    In climb milling chips start thick and thin out; in conventional milling chips start thin and grow thick — this affects cutting forces, finish, and tool life.

  5. PVD (Physical Vapor Deposition) coatings on carbide inserts differ from CVD coatings in that PVD coatings:

    Answer: Are applied at lower temperatures preserving edge sharpness

    PVD coatings are deposited at lower temperatures (around 500°C vs 1000°C for CVD), allowing sharper edge geometries to be maintained without substrate distortion.

  6. When selecting a boring bar, a length-to-diameter (L/D) ratio above 4:1 typically requires:

    Answer: Anti-vibration or dampened boring bar design

    At L/D ratios above 4:1, chatter becomes a significant risk, and dampened or heavy-metal boring bars are used to absorb vibrations.

  7. What is the primary purpose of a wiper flat (wiper insert) in turning?

    Answer: Improve surface finish at a given feed rate

    A wiper flat is a secondary flat on the insert nose that smooths the peaks left by the standard nose radius, dramatically improving surface finish.