绞盘和转塔机床外文文献翻译、中英文翻译

绞盘和转塔机床中心机床是通用机床,加工中心的一些限制是：(i) 加工前的设置时间是很长的。(ii) 正常的加工过程中只能选用一把刀具。有时候有四把刀具的正方形刀架取代了传统刀架。(iii) 设置过程中的闲置时间和两切削间隔中刀具的运动是大的。(iv) 如果操作者不适当的关注，那么到指定地点的刀具精确运动是很难达到的。所有的这些困难意味着中心机床将不会在生产中使用以消除低的生产率。因此为了提高生产率中心机床必须加以调整改进。各种各样改进后的机床有绞盘和转塔车床，半自动机床和全自动机床。在以下方面的改进基本上已经达到了：(a) 有效的加工方法(b) 多个有效的刀具(c) 全自动刀具进给(d) 在精确位置刀具的自动停止(e) 按照正确的操作次序自动控制绞盘和转塔机床的主要特征是六个方（六角）块装在床尾的一端取代正常尾座。这使得六个安装刀具座中每一个都可以根据需要包含一个或多个刀具。另外两个刀架固定在十字滑台上，一个在前面，另一个在后面。它们中的每一个每次可容纳多达四个刀具。因此，总的可以最高达到14个刀具，一个刀具安装在一个位置。转塔车床包含了全直齿齿轮，具有一系列心轴转速的重负荷轴承。转头安装在滑动座架上，滑动座架可以在床身上依次滑动。在回击期间当座架在床身上滑动时，它会自动检索下一个刀具的位置，从而减少机器的闲置时间。转塔车床刀具在进料杆上设有停行系统,可精确的控制刀具移动的实际距离.因此有可能确定和控制零件所需的刀具单独运动。支承装置工作型式可以在转塔车床中使用类似于普通车床，但是由于生产力要求较高和可重复性要求更大，一般的自动装置，例如夹头，自定心夹紧或气动夹紧均被使用。衬套有各种不同的设计。实际夹紧是由衬套沿着轴线方向推或拉的运动来完成的。有时衬套闭合期间棒料不是推前就是后拉。这可以防止因外管锁住停止使轴向运动被阻止。常常由多种转塔车床零件是从未加工的棒料加工出来的。连续进给棒料，特殊的棒料进给安排是可行的，通过确切数据越过在一转开始六角转台表面提供的障碍推进棒料。十字滑台刀架用的大部分刀具都非常类似于加工中心。成型刀具也通常用在十字滑台中。为提供更大的生产力转塔中使用了种类繁多的专用刀具。一箱工具通常用于车削工艺，因为刀具切割时也支持这个工作。它们有一把切削刀还有滚齿刀以提供对工作部件必要的支承。这有助于对杆的加工，但加工操作方面没有很好的支承。盒装刀具中也可能有至少一把切断刀，那样在提供工件支承的同时可以重复切削。组合刀具让很多复合切割刀具按规定调整以适应加工形势。它们可以同时执行一个以上的切削操作，从而减少实际操作加工所需的时间。在一个刀架上有内外切削刀具，那样工件可以达到更高的精度。许多转塔车床将装有与加工中心很相似的锥形转向装置来加工锥形物。小的锥形物可以用成型刀具生产，而内部锥形可以用锥形铰刀来加工。因此可以发现绞盘和转塔与通用机床之间的很多不同点：(一) 轴承有越来越多的各级转速允许更高的生产速率。(二) 刀架是可转位的（四把刀具）。任何一个工具都可以进入切削位置。(三) 一个有六把刀具位置的刀架取代了刀柄尾部。(四) 可以通过进给停止器来调节每一个刀具的进给。(五) 安装在同一个刀架表面的两个或以上的刀具可以同时进行切削。(六) 半熟练的操作要求。(七) 以上是用于涉及更好重复性的生产经营。转塔车床的变化是绞盘车床，其中转台可以在滑动座架上移动，滑动座架视工件的长度可以固定在床身的任何位置。因此刀具的行程局限于滑动座架的长度。这种类型通常用于小规模的机器。Capstan And Turret LathesThe center lathe is a general purpose machine tool,it has a number of limitations of center lathes are:(i) The setting time for the job in terms of holding the job is large.(ii) Only one tool can be used in the normal course. Sometimes the conventional tool post can be replaced by a square tool post with four tools.(iii) The idle times involved in the setting and movement of tools between the cuts is large.(iv) Precise movement of the tools to destined places is difficult to achieve if proper care is not taken by the operator.All these difficulties mean that the center lathe cannot be used for production work in view of the low production rate. The center lathe is thus modified to improve the production rate. The various modified lathes are turret and capstan lathes, semi-automatics and automatics.Improvements are achieved basically in the following areas:(a) work holding methods(b) multiple tool availability(c) automatic feeding of the tools(d) automatic stopping of the tools at precise locations(e) automatic control of the proper sequence of operations. The main characteristic feature of the capstan and turret lathes is the six sides (hexagonal) block mounted on one end of the bed replacing the normal tailstock. This allows for mounting six tool blocks, each one of which can contain one or more tools depending upon the requirement. Further on the cross slide, two tool posts are mounted, one in the front and the other in the rear. Each one of them can hold up to four tools each. Thus the total carrying capacity is a maximum of 14 tools when only one tool is mounted in each of the locations. The turret lathe consists of an all gear, heavy duty headstock with a greater range of spindle speeds. The turret is mounted on a saddle which in turn is sliding on the bed. When the saddle moves on the bed during the return stroke it would automatically be indexed to the next tool position, thus reducing the idle time of the machine. The tools in the turret lathe are provided with a system of stops and trips on the feed rod which can precisely control the actual distance moved by the tool. Thus it is possible to set and control the individual movements of the tools as required by the component.The type of work holding devices that can be used with turret lathe is similar to the conventional lathes, but in view of the higher productivity demanded and greater repeatability required, generally automatic fixtures such as collets, self centering chucks or pneumatic chucks are used.The collet chucks come in a variety of designs. The actual clamping is done by the movement of the collet tube along the axis of the spindle by either pushing or pulling .Sometimes the bar material is either pushed or pulled back during the closing of the collet. This can be prevented by having an external tubular locking stop so that the axial movement is prevented.Often a large variety of components on a turret lathe are machined from raw material which is in a bar from. For continuous feeding of the bar special bar feeding arrangements are available which pushes the bar by a precise amount against a stop provided on the face of the hexagonal turret at the beginning of the cycle. Most of the tools used in the cross slide tool post are very similar to those used in the center lathe. Form tools are generally used in the cross slide. A large variety of special tool holders are available for use in the turret for providing greater productivity. A box tool is generally used for long turning jobs since the tool while cutting also supports the job. They have a cutting tool and also support rollers for providing the necessary support to the workpiece. This helps in machining of bars which are not well supported during the machining operation .It is also possible to have more than one cutting tool held in a box tool such that there is an overlap of the cuts while providing support for the workpiece.Combination tool holders allow for mounting multiple cutting tools with provisions for their adjustment to suit the machining situation. They have the ability to perform more than one cutting operation at the same time, thereby reducing the actual machining time required for the operation. They can be have both the internal and external cutting tools in a single tool holder such that the workpiece support can be taken care of so that higher accuracy can be achieved.Many turret lathes would be fitted with taper turning attachments very similar to that used in center-lathes, for machining tapers. Small tapers can be produced by form tools from the cross slide, while internal tapers are produced by taper reamers.Thus the various differences that can be found between capstan and turret with that of a general purpose center lathe are:(i) The headstock has more and heavier range of speeds and to allow for higher rate of production.(ii) The tool post is indexable (four tools). Any one tool can be brought into the cutting position.(iii) The tail stock is replaced by a tool turret with six tool positions.(iv) Feed of each tool can be regulated by means of feed stops.(v) Two or more tools mounted on a single tool face can cut simultaneously.(vi) Semi-skilled operators are required.(vii) These are used for production operations involving better repeatability.A variation of the turret lathe is the capstan lathe, in which the turret moves on the saddle while the saddle can itself be fixed at any position on the bed depending upon the length of the job. Thus the tool travel length is limited to the length of the saddle. This type of arrangement is normally used for small size machines.