機械外文文獻翻譯--機床刀具設計【中文5540字】【中英文WORD】
機械外文文獻翻譯--機床刀具設計【中文5540字】【中英文WORD】,中文5540字,中英文WORD,機械,外文,文獻,翻譯,機床,刀具,設計,中文,5540,中英文,WORD
機床刀具設計
課題研究意義
機床原來的刀庫控制程序是單獨設計的，沒有采用刀具管理系統，功能也比較單一，只實現了刀庫刀具的找刀、刀庫最短路徑定位、主軸換刀，而且不支持大型刀具。
在刀庫自動選刀方面，在計算機記憶式選刀的基礎上采用了西門子840D特色功能，使選刀程序更簡潔，并完成空刀套的查找。刀庫快速換刀利用STEP-7完成編程，并在實際中得到驗證。在刀庫定位問題上，PLC程序控制采用模塊化設計方法，這對今后生產類似機床將十分有利，很容易將其利用到其他機床上。自動換刀系統將以較快的速度增長，縮短換刀時間，提高刀具的定位精度是重要的手段，有利于數控技術的發展。
刀具及其元件庫存是現代生產管理中的重要環節, 特別是大型車間管理。傳統的人工記帳管理方式, 效率低下, 錯誤率高, 且信息數據不能共享, 刀具的使用狀態和壽命周期無法跟蹤, 不能適應當前信息化管理需要。結合生產實際, 我們在車間刀具準備間建立刀具貯存立體庫系統, 以滿足車間刀輔具儲存與管理的需要。
該系統采用最優化技術, 利用計算機存儲的大量庫存信息, 能及時、準確、全面地反映刀具庫的庫存情況。整個系統采用圖形界面, 人機對話由中文菜單提示, 可實現各種功能選擇和各種信息的輸入。管理系統采用在線幫助功能?？赏ㄟ^車間管理層、網絡系統實現信息管理和共享。具有自動庫存管理、刀具入庫管理、刀具出庫管理和統計查詢功能。
1.系統組成及其控制結構
整個系統包括機械結構及電氣控制系統。
1.1.1 機械結構及工作原理
刀具庫由支架、驅動機構、傳動系統、刀架、護罩、電氣控制系統等部分組成。支架由立柱、橫梁、上下導向環軌、支撐地軌組成。
1)驅動機構 該系統選用了變頻調速的方法。采用錐形制動電機, 帶變頻調速, 經擺線針輪減速器, 通過鏈輪傳動。
2)拖動與傳動系統 采用變頻控制技術。通過變頻調速, 可使傳動軸轉速在正常范圍內調節使刀架回轉速度控制到 5～ 30mm in, 2 個傳動軸各帶上、下2 個鏈輪通過上、下2 條異形滾子鏈帶動貨架轉動。鏈條脹緊機構采用螺紋調節脹緊, 為定期脹緊方式。調節時上、下鏈條松度調節一致, 使鏈條受力均勻。
3)刀架與防護罩 整庫共有14 列獨立刀架。其中 13 列為插座式刀架, 1 列為抽屜式刀架, 每個刀架背部通過銷軸與上、下輸送鏈鏈板聯接, 底部安裝滾輪, 鏈條轉動帶動刀架沿地軌轉動。插座式刀架分BT40 刀架和BT50 刀架 2 種形式。為加強管理, 保證安全, 美化造型, 貨架外圍加防護罩。抽屜式刀架分 6 個抽屜放置其他刀輔具, 可分類裝存一些刀輔具, 如鉆頭、車刀等。
1.1.2. 電氣控制系統
本刀具儲存系統的電氣控制主要是對其貨架進行運行控制和位置控制。運行控制包括運行設備的啟動、制動控制。位置控制主要是對貨架位置和地址進行檢測。控制系統框圖如圖 1 所示。
圖 1 刀具庫控制系統圖
1)電氣傳動 水平旋轉刀具儲存系統各機械的動作都屬于反復短時工作制。而且系統在運行時需要幾種速度, 因此傳動系統需要調速, 所以該系統選用了變頻調速的方法, 可以采用結構簡單、運行可靠的變頻器和變頻電動機。
2)控制方式 該系統分為手動和自動控制2 種控制方式, 手動控制一般作為調試用和備用的工作方式; 自動控制方式為本系統計算機(IPC)和控制單元(變頻器、接觸器等)組成的一個自動控制系統。
3)位置及定位精度檢測 本系統中自動認址和位置檢測采用了接近開關作為檢測元器件, 通過光點隔離繼電器板和記數板對接近開關采集的信號進行記數和運算處理, 采用最優路徑尋址方式確定貨架的當前位置和貨架的目的位置。為了使系統定位更準確, 采用了 2 只光電開關, 分別檢測2 個貨架的2 只檢測片。
1.2.刀庫的功能
刀庫的作用是儲備一定數量的刀具，機械手實現主軸上刀具的互換}zs}a刀具的類型有盤式刀庫、鏈式刀庫等多種形式，刀庫的形式和容量要根據機床的工藝范圍來確定。
1.3.常見類型
刀庫是存儲刀具的裝置，常見的刀庫主要有以下幾種形式:
(1)轉塔式刀庫
包括水平轉塔頭和垂直轉塔頭兩種，見圖2.6a)與b):
(2)盤式刀庫
盤式刀庫中刀庫呈盤狀,刀具沿盤面垂直排列(包括徑向取刀和軸向取刀),沿盤面徑向排列或成銳角排列的形式的刀庫。結構簡單、緊湊,應用較多,但刀具單環排列,空間利用率低。見圖2.7a)~c)。若增加刀庫容量必須使刀庫的外徑增大,那么轉動慣量也相應增大,選刀運動時間長。刀具數量一般不多于32把。刀具呈多環排列的刀庫的空間利用率高,但必然使得取刀機構復雜,適用于機床空間受限制而刀庫容量又較大的場合。雙盤式結構是兩個較小容量的刀庫分置于主軸兩側,布局較緊湊,儲刀數量也相應增大,適用于中小型加工中心。
(3)鏈式刀庫
包括單環鏈和多環鏈，鏈環形式可有多種變化，見圖2.8a)~c)，基本結構見圖2. 8do
特點:適用于刀庫容量較大的場合，所占的空間小，一般適用于刀具數在30-120把。僅增加鏈條長度即可增加刀具數，可以不增加圓周速度其轉動慣量不像盤式刀庫增加的那樣大。
(4)直線式刀庫和組合刀庫
直線式刀庫結構簡單如圖2. 9，刀具單行排列，刀庫容量小，多用于數控車床和鉆床上。由于刀庫位置固定，換刀動作由主軸完成，無需機械手。組合刀庫一般是轉塔式刀庫的組合、轉塔式與盤式刀庫的組合及鏈式刀庫的組合。每單個刀庫的儲刀量較小，換刀速度快。另外還有一些密集型的鼓輪式、彈匣式和格子式刀庫，這些密集型刀庫雖.占地面積小，但由于結構限制，基本上不用于單機加工中心，多用于FMS的集中供刀系統。
1.4.刀庫的容量
刀庫的容量首先要考慮加工工藝的需要，從使用角度出發，一般為10~40把刀，刀庫的利用率會高，而結構比較緊湊。
1.5.刀具的選擇方式
(1)順序選擇將刀具按加工工序的順序，依次放入刀庫的每一個刀座內。每次換刀時，刀庫順序轉動一個刀座位置，并取出所需要的刀具，己經使用過的刀具可以放回原來的刀座內，也可以順序放入下一個刀座內。但由于刀庫中刀具在不同的工序中不能重復使用，必須增加刀庫的容量，降低了利用率。
(2)任意選擇目前大多數的數控系統都采用任意選刀的方式，其分為刀套編碼、刀具編碼和記憶式等三種。刀具編碼或刀套編碼需要在刀具或刀套上安裝用于識別的編碼條，一般都是根據二進制編碼的原理進行編碼。刀具編碼選刀方式采用了一種特殊的刀柄結構，并對每把刀具編碼。每把刀具都具有自己的代碼，因而刀具可在不同的工序中多次重復使用，換下的刀具不用放回原刀座，刀庫的容量也可相應減少。本文采用記憶式選刀，這種方式能將刀具號和刀庫中的刀套位置對應地記憶在數控系統的PLC中，無論刀具放在哪個刀套內，刀具信息都始終記存在PLC內。刀庫上裝有位置檢測裝置，可獲得每個刀套的位置。這樣刀具就可以任意取出并送回。刀庫上還設有機械原點，使每次選刀時就近選取。
1.6.刀庫的控制方式
(1)刀庫作為系統的定位軸來控制。在梯形圖中根據指令的T碼進行運算比較后輸出角度和速度指令到刀庫伺服驅動刀庫伺服電機。刀庫的容量、旋轉速度、加/減速時間等均可在系統參數中設定，此種方式不受外界因素影響定位準確、可靠但成本較高。
(2)刀庫由液壓馬達驅動，有快/慢速之分，用接近開關計數并定位。在梯形圖中比較系統存儲的當前刀號(主軸上的刀)和目標刀號(預選刀)并運算，再輸出旋轉指令，同時判斷按最短路徑旋轉到位。這種方式需要足夠的液壓動力和電磁閥刀庫旋轉速度可通過節流閥調整。但使用一段時間后可能會因為油質、油壓、油溫及環境因素的變化而影響運動速度和準確性。一般用于不需頻繁換刀的大中型機床。
(3)刀庫由交流異步電動機驅動凸輪機構(馬氏機構)，用接近開關計數，這種方式運行穩定，定位準確可靠一般與凸輪機械手配合使用，換刀速度快，定位準。
2.換刀裝置的主要類型,特點和適用范圍
2.1.自動回轉刀架
自動回轉刀架是數控機床上使用的一種簡單的自動換刀裝置，有四方刀架和六角刀架等多種形式，回轉刀架上分別安裝有四把、六把或更多的刀具，并按數控指令進行換刀。回轉刀架又有立式和臥式兩種，結構比較簡單，適用于經濟數控車床。
回轉刀架在結構上必須具有良好的強度和剛度，以承受粗加工時切削抗力和減少刀架在切削力作用下的變形，提高加工精度?；剞D刀架還要選擇可靠的定位方案和合理的定位結構，以保證回轉刀架在每次轉位之后具有較高的重復定位精度(一般為0.001 ~0.005mm )。圖2.1所示為螺旋升降式四方刀架。
在自動回轉刀架中最簡單的換刀裝置是180o回轉式換刀裝置，如圖2.2所示。接到換刀指令后，機床控制系統便將主軸控制到指定換刀位置;與此同時，刀具庫運動到適當位置，換刀裝置回轉并同時與主軸、刀具庫的刀具相配合;拉桿從主軸刀具上卸掉，換刀裝置將刀具從各自的位置上取下;換刀裝置回轉180o并將主軸刀具與刀具庫刀具帶走;換刀裝置回轉的同時，刀具庫重新調整其位置，以接受從主軸取下的刀具;接下來，換刀裝置將要換上的刀具與卸下的刀具分別裝入主軸和刀具庫:最后，換刀裝置轉回原“待命”位置。至此，換刀完成，程序繼續運行。這種換刀裝置的主要優點是結構簡單、涉及的運動少、換刀快。主要缺點是刀具必須存放在與主軸平行的平面內，與側置后置刀具庫相比，切屑及切削液易進入刀夾，因此必須對刀具另加防護。刀夾錐面上有切屑會造成換刀誤差，甚至有損壞刀夾與主軸的可能。有些加工中心使用了傳遞桿，并將刀具庫側置。當換刀指令被調用時，傳遞桿將刀具庫的刀具取下，轉到機床前方，并定位于與換刀裝置配合的位置。180o“回轉式換刀裝置既可用于臥式機床，也可用于立式機床。
2. 2.轉塔頭式換刀裝
帶有旋轉刀具的數控機床常采用此種換刀裝置，轉塔頭上裝有幾個主軸，每個主軸上均裝一把刀具，加工過程中轉塔頭可自動轉位實現換刀。其優點是結構簡單，換刀時間短，僅為2s左右。但由于受空間位置的限制，主軸數目不能太多，通常只適用于工序較少、精度要就不高的機床，如數控鉆床、數控銑床等。近年來出現了一種用機械手和轉塔頭配合刀庫進行換刀的自動換刀裝置，如圖2.3所示。它實際上是轉塔頭換刀裝置和刀庫式換刀裝置的結合。其原理如下:
轉塔頭5上有兩個刀具主軸3和4，當用刀具主軸4上的刀具進行加工時，可由機械手2將下一步需要的刀具換至不工作的刀具主軸3上，待本工序完成后，轉塔頭回轉180o，完成換刀。因其換刀時間大部分和加工時間重合，真正換刀時間只需轉塔頭轉位的時間，這種換刀方式主要用于數控鉆床和數控銼床等。
2. 3.帶刀庫的自動換刀系統
圖2.4所示為刀庫與機床為整體式數控機床的外觀圖。
圖2.5所示為刀庫與機床為分體式數控機床的外觀圖。
此時，刀庫容量大，刀具可以較重，常常附加運輸裝置來完成刀庫與主軸之間刀具的運輸。
帶刀庫的換刀裝置由刀庫、選刀機構、刀具自動裝卸機械及刀具交換機構(機械手)等四部分組成，應用廣泛。
刀庫機械手自動換刀系統，整個換刀過程比較復雜。首先要把加工過程中使用的全部刀具安裝在標準刀柄上，在機外進行尺寸預調后，按一定的方式放入刀庫。換刀時，先在刀庫中選刀，再由換刀裝置從刀庫或主軸上取刀，進行交換，將新刀裝入主軸，舊刀放回刀庫。
由于前兩種換刀裝置容納的刀具數量有限不能太多，不能滿足復雜零件的加工需要，所以自動換刀數控機床多采用帶刀庫的自動換刀裝置。刀庫具有較大容量，既可安裝在主軸箱的側面或上方。由于帶刀庫的自動換刀裝置的數控機床的主軸箱內只有一根主軸，主軸部件的剛度要高，以滿足精密加工要求。刀庫內數量較大，因而能滿足復雜零件的多工序加工，大大提高生產率。帶刀庫的自動換刀系統適用于數控鉆削中心和加工中心。進行比較得出帶刀庫的自動換刀系統是最有發展前景的。
3.PLC控制的隨機選刀方式的研究
3. 1常見的自動選刀方式
刀庫的自動控制指CNC執行用戶指令后系統對刀庫的自動控制過程，包括程序找刀和自動換刀[(63,71]。加工中心的計算機數控裝置(CNC)發出的選刀指令，將刀庫轉到所需刀具號的取刀位置，稱自動選刀。自動選刀有兩種方法:順序選刀和隨機選刀方法。
3.1.1順序選刀
順序選刀方法是刀具按預定工序的先后順序插入刀庫中，使用時按順序轉到取刀位置，用過的刀具放回原來的刀座內，也可以順序放入下一個刀座內。采用這種方式，不需要刀具識別裝置，而且驅動裝置控制也比較簡單，工作可靠，可以直接由刀庫的分度機械來實現。但刀庫中每把刀具在不同的工序中不能重復使用，如果刀具不按順序裝在刀庫中，將會產生嚴重的后果。必須增加刀具的數量和刀庫的容量，降低了刀具和刀庫的利用率。
3.1.2隨機選刀
隨機選刀方法是根據指令要求任意選擇所需要的刀具，這時必須有刀具識別裝置。刀具在刀庫中不必按照工件的加工順序排列，可任意存放的。每把刀具(或刀座)均編上代碼，自動換刀時，刀庫旋轉，每把刀具都經過“刀具識別器”接受識別。當刀具代碼與CNC指令代碼相符時該刀具被選中刀庫旋轉將刀具送到換刀位置，等待機械手來抓取。隨機選刀的優點是刀庫中刀具的排列順序與加工順序無關，相同的刀具可以重復使用。因此，刀具數量比較少，刀庫也相應的較小。隨機選刀必須對刀具編碼，以便識別。編碼主要有以下三種。
1.刀具編碼方式。采用特殊的刀柄結構進行編碼，刀柄后端的拉桿上套裝著等間距的編碼環，由鎖進螺母固定。編碼環直徑有大小直徑兩種，分別表示二進制的“1”和“0"，通過這兩個圓環的不同排列，可以得到一系列代碼。例如有六個大小直徑的圓環便可組成能區別63 ( 26-1=63)種刀具的編碼。通常全為0的代碼不許使用，以避免與刀座中沒有刀具的狀況混淆。
2.刀座編碼方式。對刀座編碼，刀具編碼，并將刀具放到與其號碼相符的刀座中。換刀時刀庫旋轉，使每個刀座位依次經過識刀器，找到刀座，刀庫便停止旋轉。這時刀柄上沒有了編碼環，使刀柄簡化。
3.編碼附件方式。這種方式有編碼鑰匙、編碼卡片、編碼桿和編碼盤等，其中應用最多的是編碼鑰匙。先給刀具都附上一把裹示該刀具號的編碼鑰匙，當把各刀具存放到刀庫的刀座中時，這樣就把鑰匙的號碼轉記道刀座中，將編碼鑰匙插進到座旁邊的鑰匙孔中給刀座編上了號碼。
結 語
重點討論了在當今制造環境下刀具存儲與管理新的模式和方法, 實際應用效果良好, 在系統集成和優化運行等方面將進一步探討, 使之具有更高理論和實際水平。
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附錄A英文文獻
Design Of Tool Machine Prop
Research significance
The original knife machine control procedures are designed individually, not used tool management system, features a single comparison, the knife only has to find the tool knife, knife positioning the shortest path, axis tool change, but does not support large-scale tool.
Automatic knife in the knife election, in the computer memory knife-election on the basis of using the Siemens 840 D features, and the election procedures knife more concise, and complete the space Daotao View. ATC use the knife rapid completion of STEP-7 programming, and have been tested in practice. In the positioning of the knife, PLC controlled modular design method, which future production of similar machines will be very beneficial, it is easy to use its other machine. Automatic tool change systems will be faster growth, reduced tool change time, increase the positioning accuracy tool is an important means to help NC technology development.
Tool and inventory components of modern production is an important link in the management, especially for large workshop management. The traditional way of account management, and low efficiency, high error rate, and not sharing information and data, tools and the use of state can not track the life cycle, are unable to meet the current information management needs. With actual production, we have to establish a workshop tool for the three-dimensional tool storage system to meet the knife workshop with auxiliary storage and management needs.
The system uses optimization technology, a large number of computer storage inventory information, timely, accurate, and comprehensive tool to reflect the inventory situation. The entire system uses a graphical interface, man-machine dialogue tips from the Chinese menu, select various functions can be realized and the importation of all kinds of information. Management system using online help function. Through the workshop management, network management and sharing of information. Have automated inventory management, warehousing management tool, a tool for the management and statistical functions.
1.System components and control structure
The entire system, including the structure and electrical machinery control systems.
1.1.1Mechanical structure and working principle
Tool from the stent, drive, drive system, Turret, shielding, control system, and electrical components. Support from the column, beam, the upper and lower guide Central track, and track support component.
1) Drive for the system chosen VVVF method. Cone used brake motors, with VVVF by Cycloid reducer through sprocket drive.
2) Drag a variable frequency drive system and control technology. VVVF adopted, will speed drive shaft in the normal range adjustment to control the speed rotary turret to 5 ~ 30mm in, the drive shaft into two, two under through sprocket, the two profiled rollers Chain driven rotating shelves. Expansion chain adopted by the thread tight regulation swelling, swelling the regular way. - Conditioned, under the same chain-of-conditioning, so that the chain of uniform.
3) Turret and shields the entire total of 14 independent Turret. 13 of them as a socket-Turret, as a drawer-Turret, each Turret back through the pin and, under the conveyor chain link chain plate, installed at the bottom roller, chain driven rotating turret rotation along the track. Outlet-Turret and BT50-BT40 Turret Turret two kinds of forms. To strengthen management, security, landscaping modeling, shelf peripherals and shields. Turret-drawer drawer placed at six other Des Voeux a knife, can be categorized with some of knife auxiliary equipment, such as bits, such as turning tools.
1.1.2.Electrical Control System
This tool storage systems is the main electrical control their shelves for operational control and position control. Operational control equipment, including operation of the start of braking control. Position Control is the main location and address of the shelves for testing. Control system as shown in Figure 1.
圖 1 Tool Control System for the
1) Electric Transmission horizontal rotary tool storage systems are the mechanical movements are repeated short-term work system. And the run-time system needs some speed, speed transmission needs, the system will use VVVF method can be used simple structure, reliable operation of the motor and frequency inverter.
2) Control of the system is divided into two kinds of manual control and automatic control, manual control as a general reserve and debugging methods of work; ways to the system control computer (IPC) and the control unit (inverter contactor , etc.) consisting of a control system.
3) location and positioning accuracy of the system automatically identify the site and location using a detection device as proximity switches, relays through the plate-point isolation and the number plate recorded close to the switching signal acquisition and operation of Hutchison with a Optimal Path addressable identify the current location and shelves of the purpose of the shelf location. In order to enable a more accurate positioning system, adopted two photoelectric switches, to detect the two shelves of the two films.
1.2.The functions of the knife
knife The is the role of reserves a certain number of tools, machine tool spindle in hand to achieve the fungibility a disc cutter knife is the type of library, the chain knives, and other means, in the form of the knife and capacity according to the Machine Tool to determine the scope of the process.
1.3.Common types
The knife is a tool storage devices, the common knife mainly in the following forms:
(1) the turret knife
Including the first level turret vertical turret and the first two, see Figure 2.6 a) and b):
(2) the disc cutter
Disc knife in the library with discoid knife, cutting tool along See how vertical arrangement (including radial and axial from knife from knife), along See how radial array into acute or arranged in the form of the knife. Simple, compact, more applications, but are ring-cutter, low utilization of space. Figure 2.7 a) to c). If the knife storage capacity must be increased to increase the diameter of the knife, then the moment of inertia also increased correspondingly, the election campaign long knife. Tool number not more than 32 general. Cutter was multi-loop order of the space utilization knife, but inevitably given the knife from complex institutions, applicable to the restricted space Machine Tool storage capacity and more occasions. Two-disc structure is two smaller capacity knife on both sides of the sub-spindle place, more compact layout, the number of certificates corresponding increase knife, apply to small and medium-sized processing center.
(3) the chain knife
? Including single-and multi-ring chain ring chain, chain link can take many forms change, see Figure 2.8 a) to c), the basic structure shown in Figure 2. 8 do
Features: knife apply to the larger capacity of the occasion, the space of the small number of generally applicable to the tool in the 30-120. Only increase the length of the chain tool will increase the number should not be increased circumferential speed of its moment of inertia of the knife does not increase the disc as large.
(4) linear combination knife and the knife library
The linear knife simple structure in Figure 2.9, tool single order, the capacity of small knife, used for CNC lathe and drill press on. Because the location of fixed knife, ATC completed action by the spindle without manipulator. The cutter knife is generally the turret combination turret with a combination of the disc cutter knife and the chain combination. Every single knife the knife certificates of smaller, faster tool change. There are also some intensive drum wheel, and the lattice-type magazine for the knife, the knife-intensive though. Small footprint, but because of structural constraints, basically not used for single processing center, the concentration used for FMS for the knife system.
1.4 Tool storage capacity
Tool storage capacity of the first to consider the needs of processing, from the use of point of view, generally 10 to 40 knives, knife will be the utilization of the high, and the structure is compact.
1.5 Tool options
(1) choose to order processing tool according to the order, followed Add to the knife every knife in the Block. Each tool change, the order of rotation of a cutter knife on location, and remove the need knives, has been used by the cutter knife can be returned to the original Block, can also order Add Block, a knife. However, as the knife in the tool in different processes can not be repeated use of the knife must increase the capacity and lower utilization rate.
(2) most of the arbitrary choice of the current system of using arbitrary NC election knives, divided into Daotao coding, coding and memory-cutter, three. Daotao coding tool code or knives or Daotao need to install the code used to identify, in accordance with the general principle of binary coding coding. Tool knife election coding method uses a special knife handle structure, and each of the coding tool. Each of the tool has its own code, thereby cutting tool can be in different processes repeatedly used, not to replace the tool back at the original knife, the knife capacity can be reduced accordingly. Memory-election this paper knife, in this way can knives and knife in the position corresponding to the Daotao memory of the PLC in the NC system, no matter which tool on the Inner knife, tool information is always there in mind, PLC . On the knife with position detection devices, will be the location of each Daotao. This tool can be removed and sent back to arbitrary. On the knife is also a mechanical origin, every election, the nearest knife selection.
1.6. Control of the knife
? (1) the knife as a system to control the positioning axis. In the ladder diagram in accordance with the instructions for computing T code comparison of the output angle and speed of instructions to the knife the knife servo drive servo motor. Tool storage capacity, rotation speed, and / deceleration time, and other system parameters can be set in such a manner free from any outside influence positioning accurate and reliable but the cost is higher.
? (2) knife from the hydraulic motor drives, fast / slow the points, with proximity switches count and positioning. In comparison ladder diagram of the current storage system knife (knife spindle) and goals knife (pre-knife) and computing, then output rotation instructions, judging by the shortest path rotation in place. This approach requires sufficient hydraulic power and electromagnetic valve knife the rotational speed can be adjusted through the throttle. But over time may be oily hydraulic, oil temperature and environmental factors impact the change in velocity and accuracy. Not generally used in large and medium-sized machine tool change frequently.
? (3) the knife from AC asynchronous motor driven cam mechanism (Markov institutions), with proximity switches count, which means stable operation, and generally accurate and reliable positioning cam used in conjunction with a mechanical hand, ATC fast-positioning.
2. ATC, the main types, characteristics, and the scope of application
2.1 Auto Rotary Tool
Rotary Tool automatically on the use of CNC machine tool is a simple installation of automatic tool change, the Quartet and 47.60 Turret Tool various forms, such as rotary turret were installed on four, six or more of the Tool , NC instructions by ATC. Rotary Tool has two vertical and horizontal, relatively simple structure, applicable to economic CNC lathe.
Rotary Tool in the structure must have good strength and stiffness, resistance to bear rough Cutting Tool in the cutting force and reduce the role of deformation and improve processing accuracy. Rotating Tool to choose reliable positioning programme structure and reasonable position, in order to ensure that each rotary turret to a higher position after repeated positioning accuracy (typically 0.001 to 0.005mm). Figure 2.1 shows the spiral movements of the Quartet Turret.
Auto Rotary Tool in the simplest of ATC, is 180 o rotary ATC devices, as shown in Figure 2.2 ATC instructions received, the machine control system put ATC spindle control to the designated location at the same time, the tool movement to the appropriate location, ATC, with the rotary axis and at the same time, the knives matching tool; drawbars from Spindle Cutting Tools rip, ATC, will be the tool from their position removed; ATC, 180 o rotary tool spindle and the tool and tool away; ATC, the Rotary At the same time, the tool refocusing its position to accept Spindle removed from the cutting tool; Next, ATC, will be replaced with the cutter knives were unloaded into the spindle and tool: Finally, back to the original ATC, "standby" position. At this point, ATC completed procedures to continue to run. This ATC, the main advantage of simple structure, the less movement, fast tool change. The main disadvantage is that knives must be kept in parallel with the axis of the plane, and after the home side compared to the tool, chip and liquid-cutting knife into the folder, it is necessary to the tool plus protection. Cone knife folder on the chip will cause ATC error, or even damage knife folders, and the possibility of spindle. Some processing centre at the transfer, and the tool side. When the ATC command is called, the transfer-cutter knives will be removed, the machine go forward, and positioning with the ATC, in line with the position. 180 o "Rotary ATC devices can be used horizontal machine, can also be used for vertical machining centers.
2. 2 ATC head-turret installed
With rotating CNC machine tool often used such ATC devices, with a few turret head spindle, each with a spindle on both knives, the first tower interim process can be automatic tool change-realization. The advantage is simple structure, tool change time is short, only about 2 s. However, due to spatial constraints, the number of spindle can not be too much, usually only apply to processes less, not to high precision machine tools, such as the NC drill, such as CNC milling machine. In recent years there has been a mechanical hand and the turret head with a knife for the automatic tool change ATC devices, as shown in Figure 2.3. It is in fact a turret head ATC, and the knife-ATC device combination. The principle is as follows:
5 turret on the first two tool spindle 3 and 4, when using the tool spindle 4 processing tool, the manipulator 2 will be the next step to the need for the tool does not work on the tool spindle 3 until after the completion of this process , the first rotary turret 180 o, ATC completed. ATC most of their time and processing time coincidence, the only real tool change time turret transposition of the first time, this approach mainly used for ATC and NC NC drilling file bed.
2. 3.Daidao system for the automatic tool change
Figure 2.4 shows the knife and the whole machine tool CNC machine tools for the appearance of Fig.
? Figure 2.5 shows the knife and split-type machine to the appearance of CNC machine tool plans.
At this point, knife storage capacity, a heavier tool can, and often additional transport unit to complete the knife between the spindle and cutting tool transport.
Daidao the knife from the ATC, the election knives, automatic loading and unloading machine tool and tool exchange institutions (manipulator), composed of four parts, used widely.
Tool Automatic Tool Change the manipulator system, the whole process more complicated ATC. We must first used in the processing of all installed in the standard tool on the knife handle in the machine outside the pre-size, according to a certain way Add to the knife. ATC, selected first in the knife knife, and then from ATC, from the knife from the knife or spindle, exchange, the new knife into the spindle, the old knife back into the knife.
? ATC, as the former two knives to accommodate a limited number can not be too many, can not meet the needs of complex parts machining, CNC machine tool Automatic Tool Change Daidao the use of the automatic tool change devices. The knife has more capacity, both installed in the spindle box side or above. As for the automatic tool change Daidao device CNC machine tool spindle box only a spindle, spindle components to high stiffness to meet the machining requirements. The number of establishments in larger knife, which can meet the more complex parts of the machining processes, significantly improving productivity. Daidao system for the automatic tool change applied to drilling centres and CNC machining centers. The comparison drawn Daidao automatic tool change system is the most promising.
3.PLC control of the knife random mode of election
3. 1Common methods of automatic election knife
Automatic control of the knife CNC refers to the system after the implementation of user instructions on the knife library automation process, including the process to find knives and automatic tool change [(63,71]. CNC Machining Center device (CNC) directive issued by the election knife , a knife, the tool required to take the knife position, said the election automatic knife. automatically elected knife There are two ways: random sequence election knives and knife election method.
3.1.1 order election knife
Tool Selection order is the process tool according to the sequence of the insert knife, the use of knives in order to take place, used knives back at the original knife, can also order Add Block, a knife. In this way, no need Tool identification devices, and drive control is a relatively simple, reliable and can be used directly from the points of the knife machinery to achieve. But the knives in each of the tool in different processes can not be reused, if the tool is installed in accordance with the order of the knife, there will be serious consequences. The need to increase the number of knives and knife the capacity of the tool and reduce the utilization of the knife.
3.1.2Random election knife
Random election under the knife is arbitrary instructions to select the required tools, then there must be tool identification devices. Tool knife in the library do not have the processing in accordance with the order of the workpiece can be arbitrary storage. Each of the tool (or knife blocks) are for a code, automatic tool change, the rotary cutter, every tool have been the "tool identification device" acceptable identification. When CNC tool code and the code in line with directives of the tool selected, the rotary cutter knives will be sent to the ATC position, waiting to grab manipulator. Random knife election is the advantage of the cutter knife in the order has nothing to do with the processing sequence, the same tool can be used repeatedly. Therefore, the relatively small number of knives, knife the corresponding smaller. Random elections knife on the tool must be coded to identify. There are three main coding.
1. Tool coding. Adopt special knife handle structure coding, the drawbars on the knife handle back-end packages such as spacing of the coding part of the lock-nut fixed. Coding diameter ring diameter of a size two, respectively, said that binary "1" and "0" to the two rings are different, can be a series of code. For example, there are six small diameter of the ring can be made to distinguish between 63 (26-1 = 63) of the coding tool. All of 0 normally not allowed to use the code, to avoid the cutter knife Block did not confuse the situation.
2. Knife Block coding. On the knife Block coding, coding tool, and tool into line with the number of knives in the Block. ATC knife when the rotation, so that each knife seats followed through knowledge knife, knife found blocks, kniv
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