鉆床和铣削外文翻译.docVIP

单位代码 学 号 分 类 号 密 级 毕业设计论文 卧式双面组合钻床前主轴箱设计 院（系）名 称： 工学院机械系 专 业 名 称： 机械设计制造及其自动化 学 生 姓 名： 陈 赛 指 导 教 师： 贾百合 年 月 日Drilling and Milling Machines Upright drilling machines or drill presses are available in a variety of sizes and types, and are equipped with a sufficient range of apindle speeds and automatic feeds to fit the neds of most industries. Speed ranges on a typical machine are from 76 to 2025 rpm., with drill feed from 0.002 to 0.020 in.per revolution of the spindle. Radial drilling machines are used to drill workpieces that are too large or cumbersome to conveniently move. The spindle with the speed and feed changing mechanism is mounted on the radial arm; by combining the movement of the radial arm around column and the movement of the spindle assembly along the arm, it is possible to align the spindle and the drill to any position within reach of the machine. For work that is too large to conveniently support on the base, the spindle assembly can be swung out over the floor and the workpiece set on the beside the machine. Plain radial drilling machines provide only for vertical movement of the spindle; universal machines allow the spindle to swivel about an axis normal to the radial arm and the radial arm to rotate about a horiz