Difficulty: Easy
Correct Answer: Down milling (climb milling)
Explanation:
Introduction / Context:
Milling direction affects chip thickness profile, cutting forces, surface finish, and fixture requirements. Choosing up or down milling is a key process decision, especially on machines with or without backlash compensation.
Given Data / Assumptions:
Concept / Approach:
In down (climb) milling, the cutter rotation matches the feed direction. Chip thickness starts at a maximum and reduces to nearly zero, often giving better surface finish and tool life, provided backlash is controlled and the work is rigidly clamped. In up (conventional) milling, the cutter rotates against the feed and chip starts from zero thickness, increasing to maximum at exit.
Step-by-Step Solution:
Verification / Alternative check:
Process diagrams in machining texts illustrate chip thickness progression for up vs. down milling, matching the stated definition.
Why Other Options Are Wrong:
Up milling: feed opposite rotation; incorrect direction.Face/End milling: describe cutter orientation, not direction of milling.Slotting: a specific operation, not a direction convention.
Common Pitfalls:
Using down milling on worn machines with backlash can cause part “pull-in.” Always ensure rigid clamping and backlash control.
Final Answer:
Down milling (climb milling)
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