絞盤和轉塔機床外文文獻翻譯、中英文翻譯

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絞盤和轉塔機床中心機床是通用機床,加工中心的一些限制是：(i) 加工前的設置時間是很長的。(ii) 正常的加工過程中只能選用一把刀具。有時候有四把刀具的正方形刀架取代了傳統(tǒng)刀架。(iii) 設置過程中的閑置時間和兩切削間隔中刀具的運動是大的。(iv) 如果操作者不適當的關注，那么到指定地點的刀具精確運動是很難達到的。所有的這些困難意味著中心機床將不會在生產中使用以消除低的生產率。因此為了提高生產率中心機床必須加以調整改進。各種各樣改進后的機床有絞盤和轉塔車床，半自動機床和全自動機床。在以下方面的改進基本上已經達到了：(a) 有效的加工方法(b) 多個有效的刀具(c) 全自動刀具進給(d) 在精確位置刀具的自動停止(e) 按照正確的操作次序自動控制絞盤和轉塔機床的主要特征是六個方（六角）塊裝在床尾的一端取代正常尾座。這使得六個安裝刀具座中每一個都可以根據需要包含一個或多個刀具。另外兩個刀架固定在十字滑臺上，一個在前面，另一個在后面。它們中的每一個每次可容納多達四個刀具。因此，總的可以最高達到14個刀具，一個刀具安裝在一個位置。轉塔車床包含了全直齒齒輪，具有一系列心軸轉速的重負荷軸承。轉頭安裝在滑動座架上，滑動座架可以在床身上依次滑動。在回擊期間當座架在床身上滑動時，它會自動檢索下一個刀具的位置，從而減少機器的閑置時間。轉塔車床刀具在進料桿上設有停行系統(tǒng),可精確的控制刀具移動的實際距離.因此有可能確定和控制零件所需的刀具單獨運動。支承裝置工作型式可以在轉塔車床中使用類似于普通車床，但是由于生產力要求較高和可重復性要求更大，一般的自動裝置，例如夾頭，自定心夾緊或氣動夾緊均被使用。襯套有各種不同的設計。實際夾緊是由襯套沿著軸線方向推或拉的運動來完成的。有時襯套閉合期間棒料不是推前就是后拉。這可以防止因外管鎖住停止使軸向運動被阻止。常常由多種轉塔車床零件是從未加工的棒料加工出來的。連續(xù)進給棒料，特殊的棒料進給安排是可行的，通過確切數據越過在一轉開始六角轉臺表面提供的障礙推進棒料。十字滑臺刀架用的大部分刀具都非常類似于加工中心。成型刀具也通常用在十字滑臺中。為提供更大的生產力轉塔中使用了種類繁多的專用刀具。一箱工具通常用于車削工藝，因為刀具切割時也支持這個工作。它們有一把切削刀還有滾齒刀以提供對工作部件必要的支承。這有助于對桿的加工，但加工操作方面沒有很好的支承。盒裝刀具中也可能有至少一把切斷刀，那樣在提供工件支承的同時可以重復切削。組合刀具讓很多復合切割刀具按規(guī)定調整以適應加工形勢。它們可以同時執(zhí)行一個以上的切削操作，從而減少實際操作加工所需的時間。在一個刀架上有內外切削刀具，那樣工件可以達到更高的精度。許多轉塔車床將裝有與加工中心很相似的錐形轉向裝置來加工錐形物。小的錐形物可以用成型刀具生產，而內部錐形可以用錐形鉸刀來加工。因此可以發(fā)現絞盤和轉塔與通用機床之間的很多不同點：(一) 軸承有越來越多的各級轉速允許更高的生產速率。(二) 刀架是可轉位的（四把刀具）。任何一個工具都可以進入切削位置。(三) 一個有六把刀具位置的刀架取代了刀柄尾部。(四) 可以通過進給停止器來調節(jié)每一個刀具的進給。(五) 安裝在同一個刀架表面的兩個或以上的刀具可以同時進行切削。(六) 半熟練的操作要求。(七) 以上是用于涉及更好重復性的生產經營。轉塔車床的變化是絞盤車床，其中轉臺可以在滑動座架上移動，滑動座架視工件的長度可以固定在床身的任何位置。因此刀具的行程局限于滑動座架的長度。這種類型通常用于小規(guī)模的機器。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.