机械专业外文翻译--机床基础(编辑修改稿)

机械专业外文翻译--机床基础(编辑修改稿)内容摘要：

a machine tool locate and guide members which move relative to each other,usually changing the position of the tool relative to the movement genenally takes the forms of translation in a straight line,but is sometimes angulai rotation,. tilting the wheelhead of a universal threadgrinding machine to an angle corresponding with the helix angle of the workpiece basic geometric elements of slides are flat,vee,dovetail and elements may be used separately or bined in various ways according to the of slideways are as follows: (a)Accuracy of a slide is to be displaced in a straight line,this line must lie in two mutually perpendicular planes and there must be no slide general tolerance for straightness of machine tool slideways is 0— per 1000mm。 on horizontal surfaces this tolerance may be disposed so that a convex surface results,thus countering the effect of “sag”of the slideway. (b)Means of facilitate assembly,maintain accuracy and eliminate “play” between slideing members after wear has taken place,a strip is something inserted in the is called a ,the grib is retained by sockethead screw passing through elongated slots。 and is adjusted by grubscrews secured by lock nuts. (c) may be lubricated by either of the following systems: 1)Intermittently through grease or oil nipples,a method suitable where movements are infrequent and speed low. 2)Continuously,. by pumping through a metering value and pipework to the point of application。 the film of oil introduced between surfaces by these means must be extremely thin to avoid the slide “floating”.If sliding surfaces were optically flat oil would be squeezed out,resulting in the surfaces in practice slide surfaces are either ground using the edge of a cup wheel,or processes produce minute surface depresssions,which retain “pocket” of oil,and plete separation of the parts may not occur at all points。 positive location of the slides is thus retained. (d) maintain slideways in good order,the following conditions must be met: 1)Ingress of foreign matter,. swarf,must be this is no possible,it is desirable to have a form of slideway,which does not retain swarf,. the inverted vee. 2)Lubricating oil must be adhensive property of oil for use on vertical 7 or inclined slide surface is important。 oils are available which have been specially developed for this adhesiveness of oil also prevents it being washed away by cutting fluids. 3)Accidental damage must be prevented by protective guards. A machine tool performs three major functions:1)it rigidly supports the workpiece or its holder and the cutting tool。 2)it provides relative motion between the workpiece and the cutting tool。 3)it provides a range of feeds and used to remove metal in the form of chips are classified in four general groups:those using singlepoint tools,those using multipoint tools,those using randompoint tools(abrasive),and those that considered special. Machines using basically the singlepoint cutting tools include:1)engine lathes, 2)turret lathes , 3)tracing and duplicating lathes, 4)singlespindle automatic lathes, 5)multisingle automatic lathes , 6)shapers and planers, 7)boring machines. Machines using multipoint cutting tools include:1)drilling machines, 2)milling machines, 3)broaching machines, 4)sawing machines, 5)gearcutting machines. Machines using randompoint cutting tools include:1)cylindrical grinder, 2)centreless grinders, 3)surface metal removal methods include:1)chemical milling, 2)electrical discharge machining, 3)ultrasonic machining. The lathe removes material by rotating the workpiece against a cutter to produce external or internal cylindrical or conical is also monly used for the production of flat surfaces by faing,in which the workpiece is rotated while the cutting tool is moved perpendicularly to the axis of rotation. The engine lathe is the basic turning machine from which other turning machines have been drive motor is located in the base and drives the spindle through a bination of belts and gears,which provides the spindle speeds from 25 to 1500 spindle is a sturdy hollow shaft,mounted between heavyduty bearings,with the forward end used for mounting a drive plate to impart positive motion to the drive plate may be fastened to the spindle by threads,by a cam lock mechanism,or by a thread collar and key. The lathe bed is cast iron and provides accurately ground sliding surfaces(way)on which the carriage lathe carriage is a Hshaped casting on which。