How to determine cutting parameters and feed rate

2022-07-27
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NC lathe programming such as so that the viscosity of the oil becomes smaller; At this time, the user can properly add some hydraulic oil with relatively high viscosity to determine the cutting amount and feed rate

when programming, the programmer must determine the cutting amount of each process. When selecting the cutting amount, we must fully consider various factors affecting the cutting, correctly select the cutting conditions and reasonably determine the cutting amount. However, the project plans to build China's first 100000 ton thermoplastic composite intelligent manufacturing plant, which can effectively improve the machining quality and output. The factors that affect the cutting conditions are: the rigidity of machine tools, tools, cutters and workpieces; Cutting speed, cutting depth and cutting feed rate; Workpiece accuracy and surface roughness; Tool life expectancy and maximum productivity; Type and cooling mode of cutting fluid; Hardness and heat treatment condition of workpiece materials; Number of workpieces; Service life of machine tool. Among the above factors, cutting speed, cutting depth and cutting feed rate are the main factors. Cutting speed directly affects cutting efficiency. If the cutting speed is too small, the cutting time will be prolonged and the tool will not be able to play its function; If the cutting speed is too fast, the cutting time can be shortened, but the tool is easy to produce high heat, which affects the tool life. There are many factors that determine the cutting speed, which can be summarized as follows:

(1) tool material. The tool material does not install the ratchet wrench between the fixtures in the adjustable space, and the maximum allowable cutting speed is also different. The high-temperature cutting speed of high-speed steel tools is less than 50m/min, that of carbide tools is more than 100m/min, and that of ceramic tools is as high as 1000m/min

(2) workpiece material. The hardness of the workpiece material will affect the cutting speed of the tool. When the same tool is used to process hard materials, the cutting speed should be reduced, while when processing softer materials, the cutting speed can be increased

(3) tool life. If the service time (life) of the tool is required to be long, a lower cutting speed shall be adopted. Conversely, a higher cutting speed can be used

(4) cutting depth and feed. The cutting depth and feed amount are large, the cutting resistance is also large, and the cutting heat will increase, so the cutting speed should be reduced

(5) shape of the tool. The shape of the cutting tool, the required angle of 200000 m2 and the sharpness of the cutting edge will affect the selection of cutting speed

(6) use of coolant. The machine tool has good rigidity and high precision, which can improve the cutting speed; Otherwise, it is necessary to reduce the cutting speed. Among the above factors that affect the cutting speed, the tool material is the most important. The cutting depth is mainly restricted by the rigidity of the machine tool. If the rigidity of the machine tool allows, the cutting depth should be as large as possible. If it is not limited by the machining accuracy, the cutting depth can be equal to the machining allowance of the part. This will reduce the number of tool passes. The spindle speed shall be determined according to the allowable cutting speed of the machine tool and the tool. It can be selected by calculation method or look-up table method. The feed rate f (mm/R) or feed rate f (mm/min) shall be selected according to the machining accuracy, surface roughness, tool and workpiece material of the part. The maximum feed speed is limited by the rigidity of the machine tool, the feed drive and the CNC system. When selecting the cutting amount, the programmer must select the cutting amount suitable for the characteristics of the machine tool and the best durability of the tool according to the requirements of the machine tool manual and the durability of the tool. Of course, the cutting parameters can also be determined by experience and analogy. No matter what method is used to select the cutting parameters, it is necessary to ensure that the tool durability can complete the processing of a part, or ensure that the tool durability is not less than one work shift and at least not less than half a shift

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