Selection of the amount of back engagement: The selection of the amount of back engagement should be determined according to the rigidity of the machine tool, fixture and workpiece, as well as the power of the machine tool. When the process system allows, select a larger amount of back-feeding knife as much as possible. Except for the allowance reserved for subsequent operations, the rest of the roughing allowance should be removed at one time as much as possible to minimize the number of passes.
Usually on medium{{0}}power machine tools, the back-cut amount of roughing is 810 mm (one side). CNC lathe factory semi-finishing back cut amount is 0.5 5 mm; back cutting amount during finishing is 0 2 1.5 mm.
Determination of feed rate: When the quality requirements of the workpiece can be guaranteed, in order to improve productivity, a higher feed rate can be selected. When the CNC lathe factory cuts off, turns deep holes or fine turning, it is advisable to choose a lower feed rate. The feed rate should be adapted to the spindle speed and the amount of back cutting. When roughing, the choice of feed is limited by the cutting force.