of a tool when it is cutting the work. 2. Feed rate is defined as tool’s distance travelled during one spindle revolution. 3. Feed rate and cutting speed determine the rate of material removal, power requirements, and surface finish.
4. Feed rate and cutting speed are mostly determined by the material that’s being cut. In addition, the deepness of the cut, size and condition of the lathe, and rigidity of the lathe should still be considered. 5. Roughing cuts (0.01 in. to 0.03 in. depth of cut) for most aluminum alloys run at a feedrate of .005 inches per minute (IPM) to 0.02 IPM while finishing cuts (0.002 in. to 0.012 in. depth of cut) run at 0.002 IPM to 0.004 IPM. 6. As the softness of the material decreases, the cutting speed increases. Additionally, as the cutting tool material becomes stronger, the cutting speed increases. 7. Remember, for each thousandth depth of cut, the diameter of the stock is reduced by two thousandths. Steel Iron Aluminum Lead Figure 1: Increasing Cutting Speed Based on work material hardness Carbon Steel High Speed Steel Carbide Figure 2: Increasing Cutting Speed Based on Cutting tool hardness
Cutting Speeds: A lathe work cutting speed may be defined as the rate at which a point on the work circumference travels past the cutting tool. Cutting speed is always expressed in meters per minute (m/min) or in feet per minute (ft/min.) industry demands that machining operations be performed as quickly as possible; therefore current cutting speeds must be used for the type of material being cut. If a cutting speed is too high, the cutting tool edge breaks down rapidly, resulting in time lost recondition the tool. With too slow a cutting speed, time will be lost for the machining operation, resulting in low production rates. Based on research and testing by steel and cutting tool manufacturers, see lathe cutting speed table below. The cutting speeds for high speed steel listed below are recommended for efficient metal removal rates. These speeds may be varied slightly to shift factors such as the condition of the machine, the type of work material and sand or hard spots in the metal. The RPM at which the lathe should be set for cutting metals is as follows: To determine the RPM of the lathe while performing procedures on it:
- Winter '14