1 问题的提出:我厂为某公司生产的一种活塞销如图1所示.壁厚10.5mm,内孔成型不要求挤压凸台,而且表面粗糙度为Ra3.2.对于这样一种壁厚较大,内孔表面粗糙度要求较严且孔内无挤压凸台的大功率、增压柴油机活塞销,采用传统的钻、扩、镗孔工艺是难于满足上述要求的.对大批量生产而言,传统生产工艺一般可使内孔表面粗糙度达到Ra6.3～Ra4左右,满足这一要求,对操作工的镗孔技术水平要求较 A question put forward: I plant for a company to produce a piston pin shown in Figure 1. Wall thickness 10.5mm, the hole does not require extrusion molding boss, and the surface roughness Ra3.2. For such a Large wall thickness, the inner surface of the hole roughness requirements and no holes in the hole boss of high-power, turbocharged diesel piston pin, the use of traditional drilling, expansion, boring process is difficult to meet the above requirements. Mass production, the traditional production process can generally make the hole surface roughness Ra6.3 ~ Ra4 or so, to meet this requirement, the operator of the boring technology level requirements more