机械工程英语翻译.doc

Drilling and Drills钻削和钻头 Drilling involves producing through or blind holes in a workpiece by forcing a tool, which rotates around its axis, against the workpiece. 钻削就是通过迫使绕自身轴线旋转的切削刀具进入工件而在其上生成通孔或盲孔。 Consequently, the range of cutting from that axis of rotation is equal to the radius of the required hole. In practice, two symmetrical cutting edges that rotate about the same axis are employed. 因此，从旋转轴线开始的切削范围等于所需孔的半径。实际上，使用的是两条围绕相同轴线旋转的对称切削刃。 Drilling operations can be carried out by using either hand drills or drilling machines. The latter differ in size and construction. Nevertheless, the tool always rotates around its axis while the workpiece is kept firmly fixed. This is contrary to drilling on a lathe. 钻削作业既能采用手钻也能采用钻床来实现。钻床在尺寸和结构上虽有差别，然而始终都是切削刀具围绕自身轴线旋转、工件稳固定位的形式。这正好与在车床上钻孔相反。 Cutting Tool for Drilling Operation In drilling operations, a cylindrical rotary-end cutting tool, called a drill, is employed. The drill can have either one or more cutting edges and corresponding flutes, which can be straight or helical. 用于钻削作业的切削刀具 在钻削作业中，要用到被称为钻头的圆柱形回转端切削刀具。钻头可以有一条或多条直的或是螺旋状的切削刃以及相应的出屑槽。 The function of the flutes is to provide outlet passages for the chips generated during the drilling operation and also to allow lubricants and coolants to reach the cutting edges and the surface being machined. Following is a survey of the commonly used drills. 出屑槽的功能是给钻削作业中产生的切屑提供排出通道，并允许润滑剂和冷却液到达切削刃和正在被加工的表面。下面是常用钻头的概述。 Twist drill. The twist drill is the most common type of drill. It has two cutting edges and two helical flutes that continue over the length of the drill body, as shown in Fig.12.1. The drill also consists of a neck and a shank that can be either straight or tapered. 麻花钻：麻花钻是最常用的钻头类型。它有两条切削刃和两条沿钻头体全长连续的螺旋状出屑槽，如图12.1所示。麻花钻还包括钻颈和钻柄，钻柄可以是直的也可以是锥形的。 In the latter case, the shank is fitted by the wedge action into the tapered socket of the spindle and has a tang, which goes into a slot in the spindle socket, thus