中英文翻譯數(shù)控機床的組成部分

1、<p><b>　　數(shù)控機床的組成部分</b></p><p>　　數(shù)控機床的組成部分包括測量系統(tǒng)、控制系統(tǒng)、伺服系統(tǒng)及開環(huán)或閉環(huán)系統(tǒng)，在對數(shù)控零件進行實際程序設(shè)計之前，了解各組成部分是重要的。</p><p>　　數(shù)控中，測量系統(tǒng)這一術(shù)語指的是機床將一個零件從基準(zhǔn)點移動到目標(biāo)點的方法。目標(biāo)點可以是鉆一個孔、銑一個槽或其它加工操作的一個確定的位置。用于數(shù)控機

2、床的兩種測量系統(tǒng)是絕對測量系統(tǒng)和增量測量系統(tǒng)。絕對測量系統(tǒng)（亦稱坐標(biāo)測量系統(tǒng)）采用固定基準(zhǔn)點（原點），所有位置信息正是以這一點基準(zhǔn)。換句話說，必須給出一個零件運動的所有位置相對于原始固定基準(zhǔn)點的尺寸關(guān)系。X和Y兩維絕對測量系統(tǒng)，每維都以原點為基準(zhǔn)。增量測量系統(tǒng)有一個移動的坐標(biāo)系統(tǒng)。運用增量系統(tǒng)時，零件每移動一次，機床就建立一個新的原點（基準(zhǔn)點）。使用增量測量系統(tǒng)時的X和Y值。注意，使用這個系統(tǒng)時，每個新的位置在X和Y軸上的值都是建立在前

3、一個位置之上的。這種系統(tǒng)的缺陷是，如果產(chǎn)生的任何錯誤沒有被發(fā)現(xiàn)與校正，則錯誤會在整個過程中反復(fù)存在。</p><p>　　用于數(shù)控設(shè)備的控制系統(tǒng)通常有兩類，即點位控制系統(tǒng)和連續(xù)控制系統(tǒng)。點位控制數(shù)控系統(tǒng)機床（有時稱為位置控制系統(tǒng)數(shù)控機床）只有沿直線運動的能力。然而，當(dāng)沿兩軸線以等值（X2.000,Y2.000)同時編程時，會形成45度斜線。點位控制系統(tǒng)常用于需確定孔位的鉆床和需進行直線銑削加工的簡單銑床上，以一系

4、列小步運動形成弧形和斜線。然而，用這種方法時，實際加工軌跡與規(guī)定的切削軌跡略有不同。</p><p>　　具有在兩個或多個坐標(biāo)軸方向上同時運動的能力的機床，歸屬連續(xù)軌跡控制或輪廓控制類機床。這些機床用于加工兩維或三維空間中各種不同大小的弧形，圓角，圓及斜角。連續(xù)軌跡控制的數(shù)控機床比點位控制的機床貴得多，在加工復(fù)雜輪廓時，一般需要計算機輔助程序設(shè)計。</p><p>　　數(shù)控伺服機構(gòu)是使工作

5、臺或滑座沿坐標(biāo)軸準(zhǔn)確運動的裝置。用于數(shù)控設(shè)備的伺服機構(gòu)常有兩種：步進電機和液壓馬達(dá)。步進電機伺服機構(gòu)常用于不太貴重的數(shù)控設(shè)備上。這些電機通常是大轉(zhuǎn)矩的伺服機構(gòu)，直接安裝在工作臺或刀座的絲杠上。大多數(shù)步進電機是由來自定子和轉(zhuǎn)子組件的磁力脈沖驅(qū)動的，這種作用的結(jié)果是電機軸轉(zhuǎn)一轉(zhuǎn)產(chǎn)生200步距。把電機軸接在10扣/英寸的絲杠上，每步能產(chǎn)生0.0005英寸的移動（1/200X1/10=0.0005英寸）。液壓伺服馬達(dá)使壓力液體流過齒輪或柱塞，從

6、而使軸轉(zhuǎn)動。絲杠和滑座的機械運動是通過各種閥和液壓馬達(dá)的控制來實現(xiàn)的。液壓伺服馬達(dá)產(chǎn)生比步進電機更大的轉(zhuǎn)矩，但比步進電機貴，且噪聲很大。大多數(shù)大型數(shù)控機床使用液壓伺服機構(gòu)。</p><p>　　使用開環(huán)系統(tǒng)的數(shù)控機床，沒有反饋信號來確保機床的坐標(biāo)軸是否運動了所需的距離。即，如果接受的輸入信號是使一特定工作臺坐標(biāo)軸移動1.000英寸，伺服裝置通常使工作臺運動1.000英寸，但無法將共子臺的實際運動與輸入信號加以比較

7、。使工作臺實際移動了1.000英寸的唯一保證是所用的伺服機構(gòu)的準(zhǔn)確性。當(dāng)然，開環(huán)系統(tǒng)比閉環(huán)系統(tǒng)便宜。閉環(huán)系統(tǒng)能將實際輸出（工作臺一英寸的運動量）與輸入信號加以比較，并對任何誤差進行了比較。用于閉環(huán)系統(tǒng)的一些反饋裝置是傳感器，電尺或磁尺以及同步器等。閉環(huán)系統(tǒng)大大增加了數(shù)控機床的準(zhǔn)確性。</p><p>　　N/C Machine tool Elements</p><p>　　N/C mac

8、hine tool elements consist of dimensioning system, servomechanisms and open- or closed-loop systems. It is important to understand each element prior to actual programming of a numerically controlled part.</p><

9、;p>　　The term measuring system in N/C refers to the method a machine tool uses to move a port from a reference point to a target point. A target point may be a certain location for drilling a hole, milling a slot, or

10、other machining operation. The two measuring systems used on N/C machines are the absolute and incremental. The absolute (also called coordinate) measuring system uses a fixed reference point (origin). It is on this poin

11、t that all positional information is based. In other words, all the </p><p>　　There are two types of control systems commonly used on N/C equipment: point-to-point and continuous path. A point-to-point contr

12、olled N/C machine tool, sometimes referred to as a positioning control type, has the capability of moving only a straight line. However, when two axes are programmed simultaneously with equal values (X2.000 in., Y2.000 i

13、n.) a 45°angle will be generated. Point-to-point systems are generally found on drilling and simple milling machine where hole location and straight mi</p><p>　　Machine tools that have the capability of

14、 moving simultaneously in two or more axes are classified as continuous-path or contouring. These machines are used for machining arcs, radii, circles, and angles of any size in two or three dimensions. Continuous-path m

15、achines are more expensive than point-to-point systems and generally require a computer to aid programming when machining complex contours.</p><p>　　N/C servomechanisms are devices used for producing accurat

16、e Movement of a table or slide along an axis. Two types of servos are commonly used on N/C equipment: electric stepping motors and hydraulic motors. Stepping motor servos are frequently used on less expensive N/C equipme

17、nt. These motors are generally high-torque power servos and mounted directly to a lead screw of a table or tool slide. Most stepping motors are actuated by magnetic pluses action from the stator and rotor assemblies. The

18、 n</p><p>　　N/C machines that use an open-loop system contain no-feedback signal to ensure that a machine axis has traveled the required distance. That is, if the input received was to move a particular tabl

19、e axis 1.000 in., the servo unit generally moves the table 1.000 in. There is no means for comparing the actual table movement with the input signal, however. The only assurance that the table has actually moved 1. 000 i