Which property does increased cutting speed primarily affect?

Increased cutting speed primarily affects the material removal rate. When a milling cutter operates at a higher speed, it can engage with the material more frequently, allowing for a greater volume of material to be removed in a given period. This results in not only enhancing productivity but also potentially improving the finish quality of the cut, as higher speeds often lead to smoother surfaces due to the reduced time for tool-wear and chip formation.

The material removal rate is a crucial metric in machining as it directly influences the efficiency and effectiveness of the machining process. While increases in speed can have some impact on tool rigidity and cooling efficiency, those effects are more indirect when compared to the direct relationship between cutting speed and material removal rate. Workpiece hardness may also be influenced by factors like cutting speed, but it does not change as a direct result of increasing the speed; it remains a characteristic of the workpiece material regardless of the speed at which it is cut.