Tool wear mechanisms in turning Crater wear on the rake face of a cutting tool primarily results in which of the following effects on the metal cutting process?

Introduction / Context:
Tool wear modes include flank wear and crater wear. Crater wear forms on the rake face due to diffusion, abrasion, and adhesion with the hot chip. Recognizing its effects helps schedule tool changes and choose cutting parameters.

Given Data / Assumptions:

• Continuous cutting of steels with HSS or carbide tools.
• Elevated interface temperatures and chip-tool contact.

Concept / Approach:
Crater wear modifies rake geometry, increasing the effective friction and altering chip flow. This raises cutting forces and temperature. The tool cross-section near the cutting edge is reduced, weakening the edge and increasing risk of chipping or breakage.

Step-by-Step Solution:
Crater forms on rake face → reduces effective rake angle.Lower effective rake → higher shear deformation and friction → higher forces and heat.Material removal of the rake face → structurally weak edge → tool failure risk increases.

Verification / Alternative check:
Tool life criteria often specify a maximum crater depth for carbide tools because performance degrades rapidly beyond that threshold.

Why Other Options Are Wrong:
Each individual effect (A, B, C) occurs; thus the most complete answer is (D) all of these.

Common Pitfalls:
Monitoring only flank wear and ignoring crater depth; misattributing rising power draw to work material instead of tool wear.

Final Answer:
all of these