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孔的铰削是机械加工中比较薄弱的一环,首先是由于铰刀的耐用性较差;其次是铰削余量为0.30mm左右,所以铰削前必须经过半精加工,很费工时;再则是工件材料太硬或太软都会影响铰削效果,前者铰削困难,后者容易出现挤裂现象,影响内孔表面质量。近年来铰刀在结构设计以及材料选择上有不少改进,如采用硬质合金制作切削刃并把刀刃部份做成可调整能重磨的结构形式,如图1所示的单刃镗铰刀。此种铰刀可以加工出精度为H7～H6的内孔,其孔形误差:圆度为0.003～0.008mm,圆柱度100∶0.005mm,表面粗糙度R_a1.25～R_a0.63。它的优点是刀刃上的径向和切向分力由分布恰当的两块硬质合金来支承。还起到导向和挤压的作用,这对提高精度和光洁度是极为有利的。单刃铰刀的加工余量比普通多刃铰
Reaming hole machining is a relatively weak part of the process, the first is due to poor durability reamer; followed by reaming allowance of about 0.30mm, so before reaming must be semi-finished, it is labor-intensive; Another is the workpiece material is too hard or too soft will affect the reaming effect, the former reaming difficult, the latter prone to cracking phenomenon, affecting the surface quality of the hole. In recent years reamer in the structural design and material selection has made many improvements, such as the use of carbide cutting edge and the blade part can be made to adjust the regrinding structure, as shown in Figure 1 single-blade boring hinge Knife. This kind of reamer can process the inner hole with the accuracy of H7 ~ H6, the hole shape error: the roundness is 0.003 ~ 0.008mm, the cylindricity is 100: 0.005mm, the surface roughness is R_a1.25 ~ R_a0.63. Its advantage is that the radial and tangential forces on the cutting edge are supported by two suitably cemented carbide. It also serves as a guide and squeeze, which is extremely beneficial for improving accuracy and finish. Single-edged reamer allowance than ordinary multi-blade hinge