钻防适过根入动作安装在主的形肌中，钻上还有柄舌入主孔中的插从西作为传转动的 靠方法 straight-shank drills a drill chuck that is,in turn,fitted into the 出毛 i118. shank own in Fig.12 2. This type of drill drilconsist sure superio 14 chini 空心钻：空心钻包括斜面、钻头体、钻颈和钻柄，如图12.2所示。这类钻头可以有三条或四条出眉槽及相 同数量的保证良好导向的导向边，这样使得加工有高精度 It can also be seen in fig.12.2 that a ore drill has flat end.The chamfer can have three or four cutting edges or lips.and the lip angle may vary between 90 and 120 在图12.2中同样能看到，空心钻具有平坦的端部。斜面可以有三或四条切削刃或钻唇，并且钻唇角可以在90°到 120°之间弯化」 Core drills are employed for enlarging previously made holes and not for originating holes.This type of drill is characterized by greater productivity,high machining accuracy,and superior quality of the drilled surfaces 空心钻用于扩大己有的孔而不是打孔。这类钻头具有较大生产率、高加工精度和优良钻削表面质量的特性。 Gun drills.Gun drills are used for drilling deep holes.All gun drills are straight-fluted,and each has a single cutting edge.A hole in the body acts as a conduit to transmit coolant under considerable pressure to the tip of the drill. 深孔钻：深孔钻用于钻深孔。所有深孔钻都是直出屑槽的，并且均为单切削刃。钻头体中有个孔作为导管 在相当大的压力下将冷却液传送到钻头顶端。 Milling and Milling Cutter 统削和铣刀 Up milling (conventional milling).In up milling the workpiece is fed against the direction of shown in Fig.12 3a. can see In that ngure, the depth of cut (and consequently 11 及作为结架的载荷)随者切削刀特续进入 如图12.3a所示。就像在此图中能看到的那 切削而逐渐增 and I nining pro life ality ecially fo 所以，这种工艺没有冲击载荷”从而保证了机床的平运行和较长寿给道所得机加表面质量不是很高。 然而逆铣仍经常被用在工业上 尤其是粗切制时。 Down milling (climb milling).As can be seen in Fig.12.3b,in down milling the cutter rotation coincides with the direction of feed at the contact point between the tool and the workpiece.it can also be se n that the maximum denth of cut is achieved directly as the cutter en ages with the 铁（同向铣削）：如同在图12.劭中看到的那样，在顺铣时刀具与工件之间接触点上铣刀旋转与进给方向 一致。还可以看到当刀具进入工件切削时直接达到最大切削深度。 This results in a kind of impact,or sudden loading.Therefore,this method cannot be used unless the milling machine is equipped with a backlash eliminator on the feed screw.The advantages of this method include higher quality of the machined surface and easier clamping of workpieces,since the cutting forces act downward. 这会导致一种冲击，或突然加载。因此，这种方法只有当铣床在进给螺栓上配备间隙消除器时才采用。这种方法的 优点包括机加工表面质量较高和工件由于切削力向下作用而较容易夹紧。 Types of Milling Cutters Plain milling cutter.A plain milling cutter is a disk-shaped cutting tool that may have either straight or helical teeth,as shown in Fig.12.4a.This type is always mounted on horizontal milling machines and is used for machining flat surfaces.8 rotation. 锥形钻柄通过楔入动作安装在主轴的锥形轴孔中，钻柄上还有柄舌插入主轴轴孔中的插槽，从而作为传递转动的可 靠方法。 On the other hand, straight-shank drills are held in a drill chuck that is, in turn, fitted into the spindle socket in the same way as tapered shank drills. 另一方面，直柄钻头用钻头卡盘夹住，接下来钻头卡盘则象锥形钻柄钻头一样安装在主轴轴孔内。 Core drills. A core drill consists of the chamfer, body, neck, and shank, as shown in Fig.12.2. This type of drill may have either three or four flutes and equal number of margins, which ensure superior guidance, thus resulting in high machining accuracy. 空心钻：空心钻包括斜面、钻头体、钻颈和钻柄，如图 12.2 所示。这类钻头可以有三条或四条出屑槽及相 同数量的保证良好导向的导向边，这样使得加工有高精度。 It can also be seen in Fig.12.2 that a core drill has flat end. The chamfer can have three or four cutting edges or lips, and the lip angle may vary between 90°and 120°. 在图 12.2 中同样能看到，空心钻具有平坦的端部。斜面可以有三或四条切削刃或钻唇，并且钻唇角可以在 90°到 120°之间变化。 Core drills are employed for enlarging previously made holes and not for originating holes. This type of drill is characterized by greater productivity, high machining accuracy, and superior quality of the drilled surfaces. 空心钻用于扩大已有的孔而不是打孔。这类钻头具有较大生产率、高加工精度和优良钻削表面质量的特性。 Gun drills. Gun drills are used for drilling deep holes. All gun drills are straight-fluted, and each has a single cutting edge. A hole in the body acts as a conduit to transmit coolant under considerable pressure to the tip of the drill. 深孔钻：深孔钻用于钻深孔。所有深孔钻都是直出屑槽的，并且均为单切削刃。钻头体中有个孔作为导管 在相当大的压力下将冷却液传送到钻头顶端。 Milling and Milling Cutter 铣削和铣刀 Up milling (conventional milling). In up milling the workpiece is fed against the direction of cutter rotation, as shown in Fig.12.3a. As we can see in that figure, the depth of cut (and consequently the load) gradually increases on the successively engaged cutting edges. 逆铣(传统铣削)：在逆铣中，工件逆着铣刀转动的方向进给，如图 12.3a 所示。就像在此图中能看到的那 样，切削深度(及作为结果的载荷)随着切削刃持续进入切削而逐渐增加。 Therefore, the machining process involves no impact loading, thus ensuring smoother operation of the machine tool and longer tool life. The quality of the machined surface obtained by up milling is not very high. Nevertheless, up milling is commonly used in industry, especially for rough cuts. 所以，这种工艺没有冲击载荷，从而保证了机床的较平稳运行和较长寿命。通过逆铣所得机加工表面质量不是很高。 然而逆铣仍经常被用在工业上，尤其是粗切削时。 Down milling (climb milling). As can be seen in Fig.12.3b, in down milling the cutter rotation coincides with the direction of feed at the contact point between the tool and the workpiece. It can also be seen that the maximum depth of cut is achieved directly as the cutter engages with the workpiece. 顺铣(同向铣削)：如同在图 12.3b 中看到的那样，在顺铣时刀具与工件之间接触点上铣刀旋转与进给方向 一致。还可以看到当刀具进入工件切削时直接达到最大切削深度。 This results in a kind of impact, or sudden loading. Therefore, this method cannot be used unless the milling machine is equipped with a backlash eliminator on the feed screw. The advantages of this method include higher quality of the machined surface and easier clamping of workpieces, since the cutting forces act downward. 这会导致一种冲击，或突然加载。因此，这种方法只有当铣床在进给螺栓上配备间隙消除器时才采用。这种方法的 优点包括机加工表面质量较高和工件由于切削力向下作用而较容易夹紧。 Types of Milling Cutters Plain milling cutter. A plain milling cutter is a disk-shaped cutting tool that may have either straight or helical teeth, as shown in Fig.12.4a. This type is always mounted on horizontal milling machines and is used for machining flat surfaces