Cutting fluids in machining: What is the primary combined purpose of applying a cutting fluid during metal cutting operations?

Introduction / Context:
Cutting fluids profoundly influence tool life, dimensional accuracy, and surface finish. They remove heat, reduce friction, and help evacuate chips, making them essential in many machining operations.

Given Data / Assumptions:

• General turning, drilling, and milling contexts.
• Appropriate fluid type for material and operation (soluble oil, straight oil, synthetic).
• Correct delivery method (flood, MQL, through-tool) assumed.

Concept / Approach:
Heat generation is intrinsic to cutting. Cutting fluids absorb and carry away heat from the cutting zone, cooling both tool and work. They also lubricate the tool–chip and tool–work interfaces, lowering friction, which improves surface finish and reduces built-up edge. Chip flushing further stabilizes the process.

Step-by-Step Solution:

Verification / Alternative check:
Tool life tests show significant improvement with proper coolant; surface roughness values decrease due to reduced friction and thermal distortion.

Why Other Options Are Wrong:

• Single-purpose choices are incomplete; fluids generally serve multiple functions simultaneously.

Common Pitfalls:
Using the wrong fluid chemistry for the work material, or inadequate flow rate/aim, negates benefits and can even worsen results due to thermal shock.

Final Answer:
All of these