Speeds and Feeds
Before using a cutting tool, it is necessary to understand tool cutting speeds and feed rates, more often referred to as “speeds and feeds.” Speeds and feeds are the cutting variables used in every operation and vary for each tool based on cutter diameter, operation, material, etc. Understanding the right speeds and feeds for your tool and operation before you start machining is critical
feed Rate = RPM * IPT * Z
RPM: rotations per minute, the revolution speed of spindle
chip load(IPT): inch per minute, the amount of material removed per revolution per flute
number of teeth (Z): the number of flutes
The chip load depends on the characteristics of the tool and of the workpiece material. For example, a tool drilling a hole into a soft workpiece material will have a higher chip load than a harder workpiece material
Generally, it would be best if you started at the lower feed rate and slowly increase it from there. For an operation such as milling, the slower the feed rate (and cutting speed), the smoother the finish on the workpiece will be.