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1、<p>  Characteristics of CNC machine tools</p><p>  CNC machine operation and monitoring of all completed in the numerical control unit, which is the brains of CNC machine tools. Compared with the gener

2、al machine tools, CNC machine tools has the following characteristics:</p><p> ?。?) high precision, stable processing quality; </p><p>  (2) can be multi-axis linkage, can process complex shape

3、parts; </p><p>  (3) processing part changes, generally only need to change the NC program, saving the production time to prepare; </p><p> ?。?) high precision machine tool itself, rigidity, can

4、 choose the amount of benefit processing, production rate (usually as an ordinary machine 3 to 5 times); </p><p> ?。?) high degree of automation tools, can reduce labor intensity; </p><p> ?。?)

5、the quality of the operators require a higher technical requirements on higher maintenance staff. </p><p>  CNC machine tools generally consists of the following components:</p><p> ?。?) host, h

6、e is the subject of CNC machine tools, including machine tools, column, spindle, feed mechanism and other mechanical parts. He is used to complete a variety of machining mechanical parts. </p><p> ?。?) CNC e

7、quipment, CNC machine tools is the core, including the hardware (printed circuit boards, CRT monitors, key boxes, paper tape reader, etc.) and the corresponding software for digital input part program, and complete the i

8、nput information storage, data transformation, interpolation operations and achieve a variety of control functions. </p><p>  (3) drive, he was the implementing agencies CNC drive components, including the s

9、pindle drive unit, feed unit, spindle motor and feed motor. He was under the control of the NC device electrical or electro-hydraulic servo system to achieve through the spindle and feed drive. When several feed linkage,

10、 you can complete the position, line, plane curves and space curves processing. </p><p> ?。?) assist device, the index control machine tools necessary supporting components to ensure the operation of CNC mac

11、hine tools, such as cooling, chip removal, lubrication, lighting, monitoring. It consists of hydraulic and pneumatic devices, chip equipment, pallet, NC rotary table and CNC dividing head, including tools and monitoring

12、detection devices. </p><p>  (5) Programming and other ancillary equipment, can be used to machine the part outside the programming and storage. </p><p>  Since 1952, Massachusetts Institute of

13、Technology developed the world since the first CNC machine tools, CNC machine tools in manufacturing industry, especially in the automotive, aerospace, and military industries has been widely used, digital technology bot

14、h in hardware and software have rapid development. </p><p>  Classification and application of CNC machine tools</p><p> ?。?) use classification by technology </p><p>  Metal cuttin

15、g type machine tools, including CNC lathes, CNC drilling, CNC milling, CNC grinding machines, CNC boring hair and processing center. These machines are suitable for single pieces, small batch and multiple varieties and p

16、arts processing, has good processing size consistency, high productivity and automation, and high equipment flexibility. </p><p>  CNC machine metal forming type; such machines, including CNC bending machine

17、s, CNC combined punch, CNC bending machine, CNC turret press and so on. </p><p>  CNC machine tools; such machines, including CNC wire (electrode) cutting machine, CNC EDM, CNC flame cutting machines, CNC la

18、ser cutting machine, special machine tool and so on. </p><p>  Other types of numerical control equipment; non-processing equipment using digital technology, such as automatic assembly machine, multi-coordin

19、ate measuring machines, automatic drawing machines and industrial robots. </p><p> ?。?)classified according to movement pattern </p><p>  Position control; point control of CNC machine tools is

20、characterized by moving parts of the machine can be achieved only from one location to another precise movement and positioning of the process in motion without any processing operations. Such as CNC drilling machines, a

21、 few at coordinate boring machine, CNC welding and tube bending machines. </p><p>  Linear control; point linear control characteristic is not only moving parts of the machine coordinates to achieve a precis

22、e location to another movement and positioning, but also to achieve a straight line parallel to the axis feed movement or control of the two oblique axes to achieve line feed movement. </p><p>  Contour cont

23、rol; contour control the characteristics of CNC machine tools is the machine moving parts to achieve two axes simultaneously control linkage. It requires not only control the moving parts of machine starting and ending c

24、oordinates of the location, but also for control of the process the speed of each point and the displacement, which called for control of the trajectories of the part processed into the plane straight line, curve or surf

25、ace in space . </p><p>  (3) Classification by control </p><p>  Open-loop control; that position feedback devices without control. </p><p>  Semi-closed loop control; refers to the

26、 open-loop control with servo motor shaft angular displacement detecting device, by detecting the servo motor to detect indirectly the corner of the displacement of moving parts back to the NC device comparator compares

27、the input command, with the difference value controls the moving parts. </p><p>  Closed-loop control; is in the final of the moving parts of machine corresponding direct linear or rotary position detection

28、device, will be directly measured value of displacement or angular displacement feedback to the CNC device with comparator compares the input command shift, with the difference value control moving parts, so that moving

29、parts in strict accordance with the actual needs of the displacement movement. </p><p> ?。?) control of machines by the number of performance categories </p><p>  Economical CNC machine tools; &

30、lt;/p><p>  Mid-range of CNC machine tools; </p><p>  High-end CNC machine tools; </p><p> ?。?) CNC equipment used by way of fractional composition of </p><p>  Hard-line

31、numerical control system; </p><p>  Soft-line numerical control system; </p><p><b>  數(shù)控機床的特點</b></p><p>  數(shù)控機床的操作和監(jiān)控全部在這個數(shù)控單元中完成,它是數(shù)控機床的大腦。與普通機床相比,數(shù)控機床有如下特點:</p>

32、<p>  (1)加工精度高,具有穩(wěn)定的加工質(zhì)量;</p><p> ?。?)可進行多坐標的聯(lián)動,能加工形狀復雜的零件;</p><p> ?。?)加工零件改變時,一般只需要更改數(shù)控程序,可節(jié)省生產(chǎn)準備時間;</p><p> ?。?)機床本身的精度高、剛性大,可選擇有利的加工用量,生產(chǎn)率高(一般為普通機床的3~5倍);</p><p&

33、gt; ?。?)機床自動化程度高,可以減輕勞動強度;</p><p> ?。?)對操作人員的素質(zhì)要求較高,對維修人員的技術(shù)要求更高。</p><p>  數(shù)控機床一般由下列幾個部分組成:</p><p>  (1)主機,他是數(shù)控機床的主題,包括機床身、立柱、主軸、進給機構(gòu)等機械部件。他是用于完成各種切削加工的機械部件。</p><p> ?。?/p>

34、2)數(shù)控裝置,是數(shù)控機床的核心,包括硬件(印刷電路板、CRT顯示器、鍵盒、紙帶閱讀機等)以及相應的軟件,用于輸入數(shù)字化的零件程序,并完成輸入信息的存儲、數(shù)據(jù)的變換、插補運算以及實現(xiàn)各種控制功能。</p><p>  (3)驅(qū)動裝置,他是數(shù)控機床執(zhí)行機構(gòu)的驅(qū)動部件,包括主軸驅(qū)動單元、進給單元、主軸電機及進給電機等。他在數(shù)控裝置的控制下通過電氣或電液伺服系統(tǒng)實現(xiàn)主軸和進給驅(qū)動。當幾個進給聯(lián)動時,可以完成定位、直線、平

35、面曲線和空間曲線的加工。</p><p> ?。?)輔助裝置,指數(shù)控機床的一些必要的配套部件,用以保證數(shù)控機床的運行,如冷卻、排屑、潤滑、照明、監(jiān)測等。它包括液壓和氣動裝置、排屑裝置、交換工作臺、數(shù)控轉(zhuǎn)臺和數(shù)控分度頭,還包括刀具及監(jiān)控檢測裝置等。</p><p>  (5)編程及其他附屬設備,可用來在機外進行零件的程序編制、存儲等。</p><p>  自從1952

36、年美國麻省理工學院研制出世界上第一臺數(shù)控機床以來,數(shù)控機床在制造工業(yè),特別是在汽車、航空航天、以及軍事工業(yè)中被廣泛地應用,數(shù)控技術(shù)無論在硬件和軟件方面,都有飛速發(fā)展。</p><p>  數(shù)控機床的分類和應用</p><p> ?。?)按工藝用途分類</p><p>  金屬切削類數(shù)控機床,包括數(shù)控車床,數(shù)控鉆床,數(shù)控銑床,數(shù)控磨床,數(shù)控鏜床發(fā)及加工中心.這些機床都

37、有適用于單件、小批量和多品種和零件加工,具有很好的加工尺寸的一致性、很高的生產(chǎn)率和自動化程度,以及很高的設備柔性。</p><p>  金屬成型類數(shù)控機床;這類機床包括數(shù)控折彎機,數(shù)控組合沖床、數(shù)控彎管機、數(shù)控回轉(zhuǎn)頭壓力機等。</p><p>  數(shù)控特種加工機床;這類機床包括數(shù)控線(電極)切割機床、數(shù)控電火花加工機床、數(shù)控火焰切割機、數(shù)控激光切割機床、專用組合機床等。</p>

38、<p>  其他類型的數(shù)控設備;非加工設備采用數(shù)控技術(shù),如自動裝配機、多坐標測量機、自動繪圖機和工業(yè)機器人等。</p><p> ?。?)按運動方式分類</p><p>  點位控制;點位控制數(shù)控機床的特點是機床的運動部件只能夠?qū)崿F(xiàn)從一個位置到另一個位置的精確運動,在運動和定位過程中不進行任何加工工序。如數(shù)控鉆床、數(shù)按坐標鏜床、數(shù)控焊機和數(shù)控彎管機等。</p>

39、<p>  直線控制;點位直線控制的特點是機床的運動部件不僅要實現(xiàn)一個坐標位置到另一個位置的精確移動和定位,而且能實現(xiàn)平行于坐標軸的直線進給運動或控制兩個坐標軸實現(xiàn)斜線進給運動。</p><p>  輪廓控制;輪廓控制數(shù)控機床的特點是機床的運動部件能夠?qū)崿F(xiàn)兩個坐標軸同時進行聯(lián)動控制。它不僅要求控制機床運動部件的起點與終點坐標位置,而且要求控制整個加工過程每一點的速度和位移量,即要求控制運動軌跡,將零件加

40、工成在平面內(nèi)的直線、曲線或在空間的曲面。</p><p>  (3)按控制方式分類</p><p>  開環(huán)控制;即不帶位置反饋裝置的控制方式。</p><p>  半閉環(huán)控制;指在開環(huán)控制伺服電動機軸上裝有角位移檢測裝置,通過檢測伺服電動機的轉(zhuǎn)角間接地檢測出運動部件的位移反饋給數(shù)控裝置的比較器,與輸入的指令進行比較,用差值控制運動部件。</p>&l

41、t;p>  閉環(huán)控制:是在機床的最終的運動部件的相應位置直接直線或回轉(zhuǎn)式檢測裝置,將直接測量到的位移或角位移值反饋到數(shù)控裝置的比較器中與輸入指令移量進行比較,用差值控制運動部件,使運動部件嚴格按實際需要的位移量運動。</p><p> ?。?)按數(shù)控制機床的性能分類</p><p><b>  經(jīng)濟型數(shù)控機床;</b></p><p>&

42、lt;b>  中檔數(shù)控機床;</b></p><p><b>  高檔數(shù)控機床;</b></p><p> ?。?)按所用數(shù)控裝置的構(gòu)成方式分類</p><p><b>  硬線數(shù)控系統(tǒng);</b></p><p><b>  軟線數(shù)控系統(tǒng);</b></p

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