What does "speed" refer to in the context of metal cutting?

In the context of metal cutting, "speed" specifically refers to the rate at which the workpiece surface and the cutting tool pass each other. This speed is measured in surface feet per minute (SFM) or meters per minute (MPM) and is crucial because it directly influences both the efficiency of the cutting process and the quality of the finished product.

When the speed is optimized, it can help achieve better material removal rates, improve tool life, and enhance surface finish on the workpiece. The relationship between cutting speed and other factors, such as feed rate and depth of cut, is critical in determining the overall productivity and performance of the machining operation. Understanding and applying the correct speed for different materials and processes enables machinists to effectively balance productivity while minimizing tool wear and defects in the machined surface.