SPINDLE SPEED
Incorrect spindle speed is a common error in CNC machining. Generally, each material and cut has an ideal tool profile and cutting speed. Larger diameter tools require slower speeds. Spindle speed and feed rate for a given cut must be balanced for best work quality, tool life and spindle life. Speed of the spindle is controlled by a FREQUENCY INVERTER. All spindles are 3-phase asynchronous motors with infinitely variable speed from 0 RPM to the Maximum rated RPM. This can be achieved by correctly programming your frequency inverter drive to match the spindle.

FEED RATE
The feed rate of the machine must be balanced with the spindle speed. Changing one influences the other. Feed rates that are too slow decrease tool life due to overheating and may leave burn marks on the work. Heat builds in the tool when not enough material is removed to cool the cut interface. Often, determining the best feed rate can only come from trial and error. The general feed rate chart for different materials is shown as a starting point. Your cutting tool supplier can advise the cutting data for your specific application.

CHIP LOAD
The inches feed per tooth (also called chip-load) determines the amount of stock that will be removed by each tooth (or flute) for a single revolution. If the chip load is too low for the material being cut, the chips will be very fine like dust and a lot of heat will be generated. If the chip load is too high for the material, the machine will push the cutter through the material rather than cutting it. This will result in high radial loads on the spindle bearings and eventual front bearing failure. See the chart to the left for generic chip load data.