In order to achieve high speed and high accuracy in boring machining, we must pay attention to the influence of tooth vibration on surface roughness and tool life. In order to prevent the machining accuracy and the decline of tool life, the selected machining centers must be equipped with a spindle with excellent dynamic balance, and the selected boring tools must have high dynamic balance characteristics. In particular, the cutter parts of boring tools should be selected for high speed cutting geometry, tool materials and clamping methods. The R at the end of the cutting edge should be larger so as to improve the machining efficiency. Under the premise of ensuring the same machined surface roughness, the feed rate should be increased. But increasing feed rate should be enough, otherwise it will increase cutting resistance, which is not conducive to improving machining efficiency. The cutting edge should be less than 0.1mm minus chamfering, which can effectively maintain the stability of tool life.
In addition to the precision machining of holes by using CNC cutting mode, boring and reaming can be used for high precision machining of holes. With the high speed spindle of the machining center, boring tools have been used for high-speed precision machining of holes. It is reported that the cutting speed can be increased to more than 1500m/min when boring about 40mm on aluminum alloy. Such cutting speed can also be applied when machining steel, cast iron and high hardness steel with CBN sintered body as cutting edge. It is predicted that the speed of boring machining will be popularized rapidly.
As for cutting tool material, the quality of the material is different. In the case of steel and other materials under the processing of 40HRC, metal ceramic tools can be used. This tool can obtain good surface roughness and longer tool life under high speed cutting conditions above v=300m/min. The coated carbide tool is suitable for high speed cutting of steel under 60HRC, and the tool life is very stable, but the cutting speed is slightly lower than that of the metal ceramic tool.
Sintered body cutter is suitable for machining high hardness steel, cast iron and other materials, cutting speed up to 1000m/min, and tool life is very stable. The blade part of the CBN cutter should be properly chamfered, which is advantageous to stable high-speed cutting and prolonging tool life. In ultra high speed cutting for nonferrous and nonmetallic materials, such as aluminum alloy, diamond sinter tool can be used. The cutting tool is stable and the tool life is long. It should be noted that when the diamond tool is used, the blade edge must be chamfered, which is an important condition to ensure the stability of cutting.
标签:   钣金加工 加工