How does a cutting fluid reduce friction during operations?

A cutting fluid reduces friction during machining operations primarily by forming a barrier between the cutting tool and the workpiece material. This barrier mitigates direct contact between the two surfaces, which minimizes wear and tear on the cutting tool and reduces heat generation due to friction. When the cutting fluid is introduced into the cutting zone, it lubricates the interface, allowing the tool to move through the material more smoothly.

The other options do have some relevance, but they do not directly address how cutting fluids primarily function to reduce friction. While cooling the surrounding area can help manage temperature and prevent thermal damage, it is the lubrication aspect that most effectively reduces friction at the cutting interface. Increasing the speed of the machine tool is more about improving productivity or efficiency rather than directly affecting friction. Lastly, hardening the workpiece material is not a function of cutting fluids; instead, it describes a property of the material itself. Thus, forming a barrier is fundamental to the role of cutting fluids in reducing friction during metal cutting operations.