数字控制 外文翻译 外文文献 英文文献.doc

NC C Numerical Control(NC) is any machining process in which the operations are executed automatically in sequences as specified by the program that contains the information for the tool NC is performed puter supervision,it is puter Numerical C).For both NC C systems,work principles are the the way in which the execution is controlled is ,new systems are faster,more powerful,andmore versatile. Using NC Early machine tools were operated by craftsmen who decided many variables such as speeds, feeds, and depth of cut, etc. With the development of science and technology, a new term, Numerical Control (NC) appeared. Controlling a machine tool using a punched tape or stored program is known as Numerical Control. NC has been defined by the Electronic Industries Association (EIA) as“A system in which actions are controlled by the direct insertion of numerical data at some point. The system must automatically interpret at least some portion of this data. ” In the past, machine tools were kept as simple as possible in order to keep their costs down. Because of the ever-rising cost of labor, better machine tools, complete with electronic controls, were developed so that industry could produce more and better products at prices that petitive with those offshore industries. NC is being used on all types of machine tools from the simplest to the plex. The mon machine tools are the single-spindle drilling machine, lathe, milling machine, turning center, and machining center. -Spindle Drilling Machine One of the simplest numerically controlled machine tools is the single-spindle drilling machine. Most drilling machines are programmed on three axes: a. The X-axis controls the table movement to the right or left. b. The Y-axis controls the table movement toward or away from the column. c. The Z-axis controls the up or down movement of the spindle to drill holes to depth. . Lathe The engine lathe, one of the most produ