机电一体化专业英语 作者 黄星 夏玉波 Unit 3.pptVIP

Turning with Power Feed One of the great features of the 7x10 is that it has a power lead-screw driven by an adjustable gear train. The lead-screw can be engaged to move the carriage under power for turning and threading operations. To change the lever setting, you must pull back on the knurled sleeve with considerable force. With the sleeve pulled back you can move the lever up and down to engage its locking pin in one of three positions. In the upper position the lead-screw rotates to move the carriage towards the headstock and in the lower position the lead-screw moves the carriage away from the headstock. 在线教务辅导网： 教材其余课件及动画素材请查阅在线教务辅导网 QQ:349134187 或者直接输入下面地址： Part I Technical and Practical Reading Passage A Machining Operations Conventional machining, one of the most important material removal methods, is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machines, and drill presses are used with a sharp cutting tool to mechanically cut the material to achieve the desired geometry. Machining is a part of the manufacture of almost all metal products. It is not uncommon for other materials to be machined. A person who specializes in machining is called a machinist. Machining is also a hobby. A room, building, or company where machining is done is called a machine shop. Much of modern day machining is controlled by computers using Computer Numerical Controlled (CNC) machining. Machining operations The three principal machining processes are classified as turning, drilling and milling. Other operations falling into miscellaneous categories include shaping, planning, boring, broaching and sawing. Turning operations are operations that rotate the work-piece as the primary method of moving metal against the cutting tool. Lathes are the principal machine tool used in turning. Milling operations are operations in which the cutting tool rotates to bring cutting edges to