Selection methods
Practice has proved that the selection of reasonable cutting parameters is related to many factors such as machine tools, tools, workpieces and processes. The methods for reasonably selecting processing parameters are as follows:
① During rough processing, the main thing is to ensure high production efficiency, so a larger back cutting amount and a larger feed rate should be selected, and the cutting speed U should be selected at a medium or low speed.
② During fine processing, the main thing is to ensure the size and surface accuracy of the parts, so a smaller back cutting amount and a smaller feed rate should be selected, and a higher cutting speed should be selected.
③ During rough processing, the potential of the machine tool and the cutting ability of the tool should generally be fully utilized. When semi-finishing and finishing, the CNC lathe factory should focus on how to ensure the processing quality and try to improve productivity on this basis. When selecting cutting parameters, the CNC lathe factory should ensure that the tool can complete a part or ensure that the tool’s durability is not less than one work shift, and at least not less than half a work shift. The specific values of the CNC lathe factory should be selected according to the provisions in the machine tool manual, the tool durability and practical experience.
Selection of back cutting depth: The selection of back cutting depth should be determined according to the rigidity of the machine tool, fixture and workpiece, etc. and the power of the machine tool. If the process system allows, choose a larger back cutting depth as much as possible. Except for the allowance left for the subsequent process, the rest of the rough machining allowance should be removed at one time as much as possible to minimize the number of passes.
Usually on medium-power machine tools, the back cutting depth of rough machining is 8~10 mm (single side). The back cutting depth of semi-finishing machining in CNC lathe factories is 0.5~5 mm; the back cutting depth during finishing is 0 2~1.5 mm.
Determination of feed rate: When the quality requirements of the workpiece can be guaranteed, a higher feed speed can be selected to improve productivity. When cutting, turning deep holes or finishing in CNC lathe factories, a lower feed speed should be selected. The feed speed should be adapted to the spindle speed and back cutting depth. During rough machining, the selection of feed rate is limited by cutting force.
