In machining operations, feed, cutting speed, and rotational speed are important parameters that determine the efficiency and quality of the machining process. Let's define each term and discuss their relationship:
Feed: Feed refers to the distance a cutting tool or workpiece advances during one complete revolution of the cutting tool or workpiece itself. It is usually measured in units of length per revolution, such as inches per revolution (IPR) or millimeters per revolution (mm/rev). Feed represents the rate at which material is removed or added during the machining process.
Cutting Speed: Cutting speed, also known as surface speed or tangential speed, is the relative velocity between the cutting tool and the workpiece material at the cutting edge of the tool. It represents the speed at which the cutting tool moves across the workpiece material during the machining process. Cutting speed is typically measured in surface feet per minute (SFM) or meters per minute (m/min).
Rotational Speed: Rotational speed, also known as spindle speed or revolutions per minute (RPM), refers to the number of complete revolutions the cutting tool or workpiece makes in one minute. It represents the rotational velocity of the cutting tool or workpiece around its axis.
The relationship between feed, cutting speed, and rotational speed can be defined by the following formula:
Cutting Speed (S) = π × Diameter of the Workpiece or Cutter (D) × Rotational Speed (N)
From the formula, it can be seen that cutting speed is directly proportional to the product of rotational speed and diameter. As cutting speed increases, the tool or workpiece moves across the material at a faster rate.
The feed rate, on the other hand, is determined by the desired material removal rate and the number of cutting edges on the tool. It is usually selected based on factors such as the material being machined, tool life, surface finish requirements, and the specific machining operation.
In summary, feed, cutting speed, and rotational speed are interconnected parameters in machining processes. The cutting speed depends on the rotational speed and the diameter of the workpiece or cutting tool, while the feed rate determines the rate at which material is removed or added during machining. Optimizing these parameters requires considering the specific machining operation, material properties, tooling, and desired outcomes.