五种基本机械加工技术外文文献翻译、机械加工工艺夹具外文翻译、中英文翻译

外文原文：  Five Basic Machining Techniques 1    The five basic techniques of machining metal include drilling and boring, turning, planing, milling, and grinding.  Variations of the five basic techniques are employed to meet special situations. 2     Drilling consists of cutting a round hole by means of rotating drill, on the other hand , involves the finishing of a hole already drilled or cored by means of a rotating, offset, single-point tool.  On some boring machines, the tool is stationary and the work revolves； on others, the reverse is true. 3    The lathe, as the turning machine is commonly called, is the father of all machine tools.  The piece of metal to be machined is rotated and the cutting tool is advanced against it. We will discuss the structure and functions of lathe in later paragraphs of this article. 4     Planing metal with a machine tool is a process similar to planing wood with a hand plane.  The essential difference lies in the fact that the cutting tool remains in a fixed position while the work is moved back and forth beneath it.  Planers are usually large pieces of equipment； sometimes large enough to handle the machining of surfaces 15 to 20 feet wide and twice as long.  A shaper differs from a planer in that the workpiece is held stationary and the cutting tool travels back and forth. 5    Milling consists of machining a piece of metal by bringing it into contact with a rotating cutting tool which has multiple cutting-edges.   There are many types of milling machines designed for various kind of work.   Some of the shapes produced by milling machines are extremely simple, like the slots and flat surfaces produced by circular saws.   Other shapes are more complex and may consist of a variety of combinations of flat and curved surfaces, depending on the shape given to the cutting-edges of the tool and on the travel path of the tool.  6   Grinding consists of shaping a piece of work by bringing it into contact with a rotating abrasive wheel.   The process is often used for the final finishing to close dimensions of a part that has been heat-treated to make it very hard.   This is because grinding can correct distortions that may have resulted from heat treatment.   In recent years, grinding has also found increased application in heavy-duty metal removal operations. 7    The Lathe： The lathe is one of the most useful and versatile machines in the workshop, and is capable of carrying out a wide variety of machining operations.  The main components of the lathe are the headstock and tailstock at opposite ends of a bed, and a tool-post between them which holds the cutting tool.   The tool-post stands on a cross-slide which enables it to move sidewards across the saddle or carriage as well as along it, depending on the kind of job it is doing.  The ordinary centre lathe can accommodate only one tool at a time on the tool-post, but a turret lathe is capable of holding five or more tools on the revolving turret. The lathe bed must be very solid to prevent the machine from bending or twisting under stress.  8     The headstock incorporates the driving and gear mechanism, and a spindle which holds the workpiece and causes it to rotate at a speed which depends largely on the diameter of the workpiece. A bar of large diameter should naturally rotate more slowly than a very thin bar； the cutting speed of the tool is what matters. Tapered centers in the hollow nose of the spindle and of the tailstock hold the work firmly between them.  9   A feed-shaft from the headstock drives the tool-post alone the saddle, either forwards or backwards, at a fixed and uniform speed. This enables the operator to make accurate cuts and to give the work a good finish. Gears between the spindle and the feed-shaft control the speed of rotation of the shaft, and therefore the forward or backward movement of the tool-post. The gear which the operator will select depends on the type of metal which he is cutting and the amount of metal he has to cut off. For a deep or roughing cut the forwards movement of the tool should be less than for a finishing cut.  10     Centers are not suitable for every job on the lathe.  The operator can replace them by various types of chucks, which hold the work between jaws, or by a front-plate, depending on the shape of the work and the particular cutting operation.  He will use a chuck, for example, to hold a short piece of work, or work for drilling, boring or screw-cutting.  11     A transverse movement of the tool-post across the saddle enables the tool to cut across the face of the workpiece and give it a flat surface.  For screw-cutting, the operator engages the lead-screw, a long screwed shaft which runs along in front of bed and which rotates with the spindle.  The lead-screw drives the tool-post forwards along the carriage at the correct speed, and this ensures that the threads on the screw are of exactly the right pitch.  The operator can select different gear speeds, and this will alter the ratio of spindle and lead-screw speeds and therefore alter the pitch of the threads.  A reversing lever on the headstock enables him to reverse the movement of the carriage and so bring the tool back to its original position. 译文：  五种基本机械加工技术   加工金属的五个基本技术包括钻，镗，车，刨，铣，磨。五项基本技术的变化是采用以满足特殊情况。  钻孔切割旋转另一方面演习，是指一个圆洞组成，涉及到一个已经钻孔或由一个旋转，偏移，单点工具手段芯孔精加工。在一些无聊的机器，工具和工作运转平稳，对他人， 情况恰恰相反。  车床，车床，是为俗称，是所有机床的父亲。对被加工金属片的旋转和刀具是反对的先进。我们将讨论在本文稍后的段落中的车床的结构和功能。  刨机床与金属是一个过程，类似于用一只手刨木机。本质区别在于一个事实，即刀具在一个固定的位置，而这项工作仍然是前后移动的下方。刨床通常是件大型设备，有时大到足以处理的表面加工 15 至 20 英尺宽的两倍。一个成型机不同于在那举行的固定工件和刀具刨来回旅行。  铣削加工包括通过将接触到一个旋转的切割工具，它具有多种先进的边缘有一块金属。也有各项工作铣削机种设计多种类型。所产生 的形状铣床一些非常简单，如圆盘锯槽和生产平面上。其他形状较为复杂，可能包括一系列的平面和曲面多种组合，这取决于给予切削工具的边缘形状和刀具的移动路径。  成型磨削包括通过使接触到它的旋转砂轮的作品。这一过程通常是用于最后的收尾来关闭一个已经热零件尺寸处理，使其很辛苦。这是正确的，因为磨削可能因热处理造成的扭曲。近年来，磨也发现增加了重型金属切除手术中的应用。  车床：该车床是车间里最有用的和通用的机器之一，是开展加工业务的各种能力。该车床的主要部件是一个车头和车尾两端床，一个工具，它们之间的职位，而持有刀具。在 跨幻灯片，使它能够跨越马鞍或