CNC machining is a subtractive manufacturing process that involves shearing away material chips until the final product is achieved. So first, the machinists need to know the amount of material the machine will shear off in one revolution and the speed at which the CNC machine will move.
When designing the parts for CNC machining, it is important to consider these parameters. This is because they ensure the optimization of different parts of the CNC machining process. While cutting speed is more important in optimizing factors like tool life and power consumption, the feed rate is vital in determining the machining time and roughness of the finished area.
What is Cutting Speed?
Cutting speed is generally defined as the relative velocity between the surface of the workpiece and the cutting tool. Some experts also define it as how fast the workpiece moves past the cutting edge of the tool. Machinists measure it in meters per minute (m/min) or feet per minute (ft/min). The cutting speed is a quite important factor in the determination of other parameters of CNC machining, such as cutting temperature, power consumption, tool life, etc. Its influence in these parameters serves as a significant difference between feed rate and cutting speed.
What is Feed Rate?
Feed rate is the distance which the cutting tool during one spindle revolution. It is also defined as the velocity at which the cutter is advanced against the workpiece. It is measured in either inch per revolution or millimeters per revolution (ipr or mpr) for turning and boring processes. However, machinists use the inches per minute or millimeters per minute (ipm or mpm) for milling processes. In calculating the feed rate, the machinist considers the number of flutes (or teeth) the cutting tool has and calculates the feed rate for each tooth.