Which statement best describes the relationship between cutting speed and tool life in drilling and milling?

• A. Increasing speed generally reduces tool life
• B. Increasing speed always increases tool life
• C. Cutting speed has no impact on tool life
• D. Only feed rate affects tool life

Answer: (A)

The key idea is that cutting speed and tool life are inversely related in metal cutting. When you raise cutting speed, more heat is generated at the cutting edge, which speeds up wear mechanisms like abrasion, diffusion, and oxidation. In drilling and milling, this extra wear typically shortens how long a tool lasts, so tool life generally decreases as speed increases. This is captured by the idea that tool life t decreases as speed V increases (often expressed in the Taylor tool life framework). It’s not that speed has no effect or that only feed rate matters; while higher speeds can boost productivity under the right conditions (coolant, coatings, and appropriate feeds), the usual trade-off is reduced tool life with higher speed.