外文翻译--数控机床的特点

西北工业大学明德学院本科毕业设计论文Characteristics of CNC machine toolsCNC machine operation and monitoring of all completed in the numerical control unit, which is the brains of CNC machine tools. Compared with the general machine tools, CNC machine tools has the following characteristics:（1） high precision, stable processing quality; （2） can be multi-axis linkage, can process complex shape parts; （3） processing part changes, generally only need to change the NC program, saving the production time to prepare; （4） high precision machine tool itself, rigidity, can choose the amount of benefit processing, production rate (usually as an ordinary machine 3 to 5 times); （5） high degree of automation tools, can reduce labor intensity; （6） the quality of the operators require a higher technical requirements on higher maintenance staff. CNC machine tools generally consists of the following components:（1） host, he is the subject of CNC machine tools, including machine tools, column, spindle, feed mechanism and other mechanical parts. He is used to complete a variety of machining mechanical parts. （2） CNC equipment, CNC machine tools is the core, including the hardware (printed circuit boards, CRT monitors, key boxes, paper tape reader, etc.) and the corresponding software for digital input part program, and complete the input information storage, data transformation, interpolation operations and achieve a variety of control functions. （3） drive, he was the implementing agencies CNC drive components, including the spindle drive unit, feed unit, spindle motor and feed motor. He was under the control of the NC device electrical or electro-hydraulic servo system to achieve through the spindle and feed drive. When several feed linkage, you can complete the position, line, plane curves and space curves processing. （4） assist device, the index control machine tools necessary supporting components to ensure the operation of CNC machine tools, such as cooling, chip removal, lubrication, lighting, monitoring. It consists of hydraulic and pneumatic devices, chip equipment, pallet, NC rotary table and CNC dividing head, including tools and monitoring detection devices. （5） Programming and other ancillary equipment, can be used to machine the part outside the programming and storage. Since 1952, Massachusetts Institute of Technology developed the world since the first CNC machine tools, CNC machine tools in manufacturing industry, especially in the automotive, aerospace, and military industries has been widely used, digital technology both in hardware and software have rapid development. Classification and application of CNC machine tools（1） use classification by technology Metal cutting type machine tools, including CNC lathes, CNC drilling, CNC milling, CNC grinding machines, CNC boring hair and processing center. These machines are suitable for single pieces, small batch and multiple varieties and parts processing, has good processing size consistency, high productivity and automation, and high equipment flexibility. CNC machine metal forming type; such machines, including CNC bending machines, CNC combined punch, CNC bending machine, CNC turret press and so on. CNC machine tools; such machines, including CNC wire (electrode) cutting machine, CNC EDM, CNC flame cutting machines, CNC laser cutting machine, special machine tool and so on. Other types of numerical control equipment; non-processing equipment using digital technology, such as automatic assembly machine, multi-coordinate measuring machines, automatic drawing machines and industrial robots. （2）classified according to movement pattern Position control; point control of CNC machine tools is characterized by moving parts of the machine can be achieved only from one location to another precise movement and positioning of the process in motion without any processing operations. Such as CNC drilling machines, a few at coordinate boring machine, CNC welding and tube bending machines. Linear control; point linear control characteristic is not only moving parts of the machine coordinates to achieve a precise location to another movement and positioning, but also to achieve a straight line parallel to the axis feed movement or control of the two oblique axes to achieve line feed movement. Contour control; contour control the characteristics of CNC machine tools is the machine moving parts to achieve two axes simultaneously control linkage. It requires not only control the moving parts of machine starting and ending coordinates of the location, but also for control of the process the speed of each point and the displacement, which called for control of the trajectories of the part processed into the plane straight line, curve or surface in space . （3） Classification by control Open-loop control; that position feedback devices without control. Semi-closed loop control; refers to the open-loop control with servo motor shaft angular displacement detecting device, by detecting the servo motor to detect indirectly the corner of the displacement of moving parts back to the NC device comparator compares the input command, with the difference value controls the moving parts. Closed-loop control; is in the final of the moving parts of machine corresponding direct linear or rotary position detection device, will be directly measured value of displacement or angular displacement feedback to the CNC device with comparator compares the input command shift, with the difference value control moving parts, so that moving parts in strict accordance with the actual needs of the displacement movement. （4） control of machines by the number of performance categories Economical CNC machine tools; Mid-range of CNC machine tools; High-end CNC machine tools; （5） CNC equipment used by way of fractional composition of Hard-line numerical control system; Soft-line numerical control system; 数控机床的特点数控机床的操作和监控全部在这个数控单元中完成，它是数控机床的大脑。与普通机床相比，数控机床有如下特点：（1）加工精度高，具有稳定的加工质量；（2）可进行多坐标的联动，能加工形状复杂的零件；（3）加工零件改变时，一般只需要更改数控程序，可节省生产准备时间；（4）机床本身的精度高、刚性大,可选择有利的加工用量，生产率高（一般为普通机床的35倍）；（5）机床自动化程度高，可以减轻劳动强度；（6）对操作人员的素质要求较高，对维修人员的技术要求更高。数控机床一般由下列几个部分组成：（1）主机，他是数控机床的主题，包括机床身、立柱、主轴、进给机构等机械部件。他是用于完成各种切削加工的机械部件。（2）数控装置，是数控机床的核心，包括硬件（印刷电路板、CRT显示器、键盒、纸带阅读机等）以及相应的软件，用于输入数字化的零件程序，并完成输入信息的存储、数据的变换、插补运算以及实现各种控制功能。（3）驱动装置，他是数控机床执行机构的驱动部件，包括主轴驱动单元、进给单元、主轴电机及进给电机等。他在数控装置的控制下通过电气或电液伺服系统实现主轴和进给驱动。当几个进给联动时，可以完成定位、直线、平面曲线和空间曲线的加工。（4）辅助装置，指数控机床的一些必要的配套部件，用以保证数控机床的运行，如冷却、排屑、润滑、照明、监测等。它包括液压和气动装置、排屑装置、交换工作台、数控转台和数控分度头，还包括刀具及监控检测装置等。（5）编程及其他附属设备，可用来在机外进行零件的程序编制、存储等。自从1952年美国麻省理工学院研制出世界上第一台数控机床以来，数控机床在制造工业，特别是在汽车、航空航天、以及军事工业中被广泛地应用，数控技术无论在硬件和软件方面，都有飞速发展。数控机床的分类和应用（1）按工艺用途分类金属切削类数控机床,包括数控车床,数控钻床,数控铣床,数控磨床,数控镗床发及加工中心.这些机床都有适用于单件、小批量和多品种和零件加工，具有很好的加工尺寸的一致性、很高的生产率和自动化程度，以及很高的设备柔性。金属成型类数控机床；这类机床包括数控折弯机，数控组合冲床、数控弯管机、数控回转头压力机等。数控特种加工机床；这类机床包括数控线（电极）切割机床、数控电火花加工机床、数控火焰切割机、数控激光切割机床、专用组合机床等。其他类型的数控设备；非加工设备采用数控技术，如自动装配机、多坐标测量机、自动绘图机和工业机器人等。（2）按运动方式分类点位控制；点位控制数控机床的特点是机床的运动部件只能够实现从一个位置到另一个位置的精确运动，在运动和定位过程中不进行任何加工工序。如数控钻床、数按坐标镗床、数控焊机和数控弯管机等。直线控制；点位直线控制的特点是机床的运动部件不仅要实现一个坐标位置到另一个位置的精确移动和定位，而且能实现平行于坐标轴的直线进给运动或控制两个坐标轴实现斜线进给运动。轮廓控制；轮廓控制数控机床的特点是机床的运动部件能够实现两个坐标轴同时进行联动控制。它不仅要求控制机床运动部件的起点与终点坐标位置，而且要求控制整个加工过程每一点的速度和位移量，即要求控制运动轨迹，将零件加工成在平面内的直线、曲线或在空间的曲面。（3）按控制方式分类开环控制；即不带位置反馈装置的控制方式。半闭环控制；指在开环控制伺服电动机轴上装有角位移检测装置，通过检测伺服电动机的转角间接地检测出运动部件的位移反馈给数控装置的比较器，与输入的指令进行比较，用差值控制运动部件。闭环控制：是在机床的最终的运动部件的相应位置直接直线或回转式检测装置，将直接测量到的位移或角位移值反馈到数控装置的比较器中与输入指令移量进行比较，用差值控制运动部件，使运动部件严格按实际需要的位移量运动。（4）按数控制机床的性能分类经济型数控机床；中档数控机床；高档数控机床；（5）按所用数控装置的构成方式分类硬线数控系统；软线数控系统；0