Selection method

Practice has proven that the selection of reasonable cutting parameters is related to various factors such as machine tools, cutting tools, workpieces, and processes. The method for selecting the appropriate processing dosage is as follows:
① When rough machining, it is mainly necessary to ensure high production efficiency, so a larger back cutting amount, a larger feed rate, and a medium low cutting speed U should be selected.
② When precision machining, the main requirement is to ensure the size and surface accuracy of the parts, so a smaller back cutting amount, a smaller feed rate, and a higher cutting speed are chosen.
③ During rough machining, it is generally necessary to fully utilize the potential of the machine tool and the cutting ability of the cutting tool. When CNC lathe factories perform semi precision machining and precision machining, they should focus on how to ensure machining quality and maximize productivity on this basis. When selecting cutting parameters, CNC lathe factories should ensure that the cutting tools can complete a part or ensure that the durability of the tools is not less than one work shift, and at least not less than half a work shift. The specific values for CNC lathe factories should be selected based on the specifications in the machine tool manual, tool durability, and practical experience.

CNC lathe
The selection of back cutting amount: The selection of back cutting amount should be determined based on the stiffness of the machine tool, fixture, workpiece, and the power of the machine tool. If the process system allows, choose a larger back cutting amount as much as possible. Except for the allowance left for future processes, the remaining rough machining allowance should be cut off as much as possible in one go to minimize the number of cutting times.

Usually on medium power machine tools, the back cutting amount for rough machining is 8-10 mm (single-sided). The back cutting amount for semi precision machining in CNC lathe factories is 0.5~5 mm; during precision machining, the back cutting amount is 0~1.5 mm.

Determination of feed rate: When the quality requirements of the workpiece can be guaranteed, a higher feed rate can be selected to improve productivity. When cutting, turning deep holes or precision turning in CNC lathe factories, it is advisable to choose a lower feed rate. The feed rate should be adapted to the spindle speed and back cutting amount. The selection of feed rate during rough machining is limited by cutting force.