In order to achieve high-speed and high-precision boring, it is necessary to pay attention to the influence of tool tooth vibration on surface roughness and tool life. In order to prevent the reduction of machining accuracy and tool life, the selected machining center must be equipped with a spindle with excellent dynamic balancing performance, and the selected boring tool must also have high dynamic balancing characteristics. In particular, the teeth of the boring cutter should be selected in a geometric, tool material and clamping method suitable for high-speed cutting. The R at the end of the cutting edge should be larger to improve the machining efficiency; On the premise of ensuring the same surface roughness, the feed should be increased. However, increasing the feed volume should be sufficient, otherwise it will increase the cutting resistance, which is not conducive to improving the processing efficiency. The cutting edge should be set with a negative chamfer of less than 0.1mm, which can effectively maintain the stability of the tool life.
In addition to CNC precision machining of holes, high-precision machining of holes can also be performed by boring and reaming. In conjunction with the high-speed spindle of the machining center, high-speed precision machining of holes can be performed using boring cutters. According to reports, when boring φ40mm on aluminum alloy materials, the cutting speed can be increased to more than 1500m/min. This cutting speed can also be used to machine steel, cast iron and high-hardness steels with CBN sintered bodies as cutting edges. It is expected that high-speed machining of boring holes will become rapidly gaining popularity in the future.
As for the tool material, it depends on the nature of the material being machined. For example, when machining materials such as steel with 40 HRC or less, cermet tools can be used. This type of tool can achieve good surface roughness and long tool life under high-speed cutting conditions of v=300m/min or more. Coated carbide tools are suitable for high-speed cutting of steel below 60HRC. The tool life is stable, but the cutting speed is slightly lower than that of cermet tools. The sintered body tool is suitable for processing materials such as high-hardness steel and cast iron. The cutting speed can reach more than 1000m/min, and the tool life is very stable.
The cutting edge part of the CBN tooth should be chamfered properly, which is extremely beneficial for stable high-speed cutting and prolonged tool life. When performing ultra-high-speed cutting of non-metallic materials such as non-ferrous metals and aluminum alloys, diamond sintered tools can be used, which has stable cutting and long tool life. It should be noted that when using diamond tools, the cutting edge must be chamfered, which is an important condition to ensure cutting stability.