數(shù)控技術(shù)---外文翻譯

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A is of of to is is to in , Y in to be at an be a 2CL C L . a in , Y, Z be be a or a 3c C of of of is no or of to In of an to of on a N／ C to no be to to ／ C to to in in of of to or to In in of ／ C Of is as a is of in of to is a in is by of of as it is to a in a to of In is to In a is so is is in a in is as a It of a on In or of it is of a in A is a an of of be of 1． In a is by in of is of of be by of to of is 2． In is at to is of of of on of of is by of a of 16—1． on is on be in by 16in up of in is in as As 16— 2， of is in In up is at in a to it to of in of in a to so be In of on of In to at to of in be if is to be It be on of as in a at of is to up is of is to to be is or a of is of at of a as to an be is to on as 1． on by a of be or 2． In or of is an of as of by of of of is to of a so be on an or be in in a to of a or or on of is or in a at a a of is to or of be or in or on an to in an of to to as a to by to on on a in ／ 32 ／ 16 to of 數(shù)控技術(shù) 數(shù)控是可編程自動(dòng)化技術(shù)的一種形式，通過(guò)數(shù)字、字母和其他符號(hào)來(lái)控制加工設(shè)備。數(shù)字、字母和符號(hào)用適當(dāng)?shù)母袷骄幋a為一個(gè)特定工件定義指令程序。當(dāng)工件改變時(shí)，指令程序就改變。這種改變程序的能力使數(shù)控適合于中、小批量生產(chǎn)，寫一段新程序遠(yuǎn)比對(duì)加工設(shè)備做大的改動(dòng)容易得多。 數(shù)控機(jī)床有兩種基本形式：點(diǎn)位控制和連續(xù)控制 (也稱為輪廓控制 )。點(diǎn)位控制機(jī)床采用異步電動(dòng)機(jī)，因此，主軸的定位只能通過(guò)完成一個(gè)運(yùn)動(dòng)或一個(gè)電動(dòng)機(jī)的轉(zhuǎn)動(dòng) 來(lái)實(shí)現(xiàn)。這種機(jī)床主要用于直線切削或鉆 孔 、鏜孔等場(chǎng)合。 數(shù)控系統(tǒng)由下列組件組成：數(shù)據(jù)輸入裝置，帶控制單元的磁帶閱讀機(jī)，反饋裝置和切削機(jī)床或其他形式的數(shù)控設(shè)備。 數(shù)據(jù)輸人裝置，也稱“人機(jī)聯(lián)系裝置”，可用人工或全自動(dòng)方法向機(jī)床提供數(shù)據(jù)。人工方法作為輸人數(shù)據(jù)唯一方法時(shí)，只限于少量輸入。人工輸入裝置有鍵盤，撥號(hào)盤，按鈕，開關(guān)或撥輪選擇開關(guān)，這些都位于機(jī)床附近的一個(gè)控制臺(tái)上。撥號(hào)盤通常連到一個(gè)同步解析器或電位計(jì)的模擬裝置上。在大多數(shù)情況下，按鈕、開關(guān)和其他類似的旋鈕是數(shù)據(jù)輸入元件。人工輸入需要操作者控制 每個(gè)操作，這是一個(gè)既慢又單調(diào)的過(guò)程，除了簡(jiǎn)單加工場(chǎng)合或特殊情況，已很少使用。 幾乎所有情況下，信息都是通過(guò)卡片、穿孔紙帶或磁帶自動(dòng)提供給控制單元。在傳統(tǒng)的數(shù)控系統(tǒng)中，八信道穿孔紙帶是最常用的數(shù)據(jù)輸入形式，紙帶上的編碼指令由一系列稱為程序塊的穿 孔 組成。每一個(gè)程序塊代表一種加工功能、一種操作或兩者的組合。紙帶上的整個(gè)數(shù)控程序由這些連續(xù)數(shù)據(jù)單元連接而成。帶有程序的長(zhǎng)帶子像電影膠片一樣繞在盤子上，相對(duì)較短的帶子上的程序可通過(guò)將紙帶兩端連接形成一個(gè)循環(huán)而連續(xù)不斷地重復(fù)使用。帶子一旦安裝好，就可反復(fù)使用而無(wú)需進(jìn) 一步處理。此時(shí)，操作者只是簡(jiǎn)單地上、下工件。穿孔紙帶是在帶有特制穿孔附件的打字機(jī)或直接連到計(jì)算機(jī)上的紙帶穿 孔 裝置上做成的。紙帶制造很少不出錯(cuò)，錯(cuò)誤可能由編程、卡片穿孔或編碼、紙帶穿孔時(shí)的物理?yè)p害等形成。通常，必須要試走幾次來(lái)排除錯(cuò)誤，才能得到一個(gè)可用的工作紙帶。 雖然紙帶上的數(shù)據(jù)是自動(dòng)進(jìn)給的，但實(shí)際編程卻是手工完成的，在編碼紙帶做好前，編程者經(jīng)常要和一個(gè)計(jì)劃人員或工藝工程師一起工作，選擇合適的數(shù)控機(jī)床，決定加工材料，計(jì)算切削速度和進(jìn)給速度，決定所需刀具類型，仔細(xì)閱讀零件圖上尺寸，定下合適的程序開始的 零參考點(diǎn)，然后寫出程序清單，其上記載有描述加工順序的編碼數(shù)控指令，機(jī)床按順序加工工件到圖樣要求。 控制單元接受和儲(chǔ)存編碼數(shù)據(jù)，直至形成一個(gè)完整的信息程序塊，然后解釋數(shù)控指令，并引導(dǎo)機(jī)床得到所需運(yùn)動(dòng)。 為更好理解控制單元的作用，可將它與撥號(hào)電話進(jìn)行比較，即每撥一個(gè)數(shù)字，就儲(chǔ)存一個(gè)，當(dāng)整個(gè)數(shù)字撥好后，電話就被激活，也就完成了呼叫。 裝在控制單元里的紙帶閱讀機(jī)，通過(guò)其內(nèi)的硅光二極管，檢測(cè)到穿過(guò)移動(dòng)紙帶上的孔漏過(guò)的光線，將光束轉(zhuǎn)變成電能，并通過(guò)放大來(lái)進(jìn)一步加強(qiáng)信號(hào)，然后將信號(hào)送到控制單元里 的寄存器，由它將動(dòng)作信號(hào)傳到機(jī)床驅(qū)動(dòng)裝置。 有些光電裝置能以高達(dá)每秒 1000 個(gè)字節(jié)的速度閱讀，這對(duì)保持機(jī)床連續(xù)動(dòng)作是必須的，否則，在輪廓加工時(shí)，刀具可能在工件上產(chǎn)生劃痕。閱讀裝置必須要能以比控制系統(tǒng)處理數(shù)據(jù)更快的速度來(lái)閱讀數(shù)據(jù)程序塊。 反饋裝置是用在一些數(shù)控設(shè)備上的安全裝置，它可連續(xù)補(bǔ)償控制位置與機(jī)床運(yùn)動(dòng)滑臺(tái)的實(shí)際位置之間的誤差。裝有這種直接反饋檢查裝置的數(shù)控機(jī)床有一個(gè)閉環(huán)系統(tǒng)裝置。位置控制通過(guò)傳感器實(shí)現(xiàn)，在實(shí)際工作時(shí)，記錄下滑臺(tái)的位置，并將這些信息送回控制單元。接受到的信號(hào)與紙帶輸入的信號(hào) 相比較，它們之間的任何偏差都可得到糾正。 在另一個(gè)稱為開環(huán)的系統(tǒng)中，機(jī)床僅由響應(yīng)控制器命令的步進(jìn)電動(dòng)機(jī)驅(qū)動(dòng)定位，工件的精度幾乎完全取決于絲杠的精度和機(jī)床結(jié)構(gòu)的剛度。 有幾個(gè)理由可以說(shuō)明步進(jìn)電機(jī) 是一個(gè)自動(dòng)化申請(qǐng)的非常有用的 驅(qū)動(dòng)裝置 。對(duì)于一件事物，它被不連續(xù)直流電壓脈 沖 驅(qū)使 ,是來(lái)自數(shù)傳計(jì)算機(jī)和其他的自動(dòng)化的非常方便的輸出控制系統(tǒng)。 當(dāng)多數(shù)是索引或其他的自動(dòng)化申請(qǐng)所必備者的時(shí)候， 步進(jìn)電機(jī) 對(duì)運(yùn)行一個(gè)精確的有角進(jìn)步也是理想的。因?yàn)榭刂葡到y(tǒng)不需要監(jiān)聽就提供特定的輸出指令而且期待系統(tǒng)適當(dāng)?shù)胤磻?yīng)的公開 - 環(huán)操作造成一 個(gè)回應(yīng)環(huán)， 步進(jìn)電機(jī) 是理想的。 一些工業(yè)的機(jī)械手使用高抬腿運(yùn)步的馬乘汽車駕駛員，而且 步進(jìn)電機(jī) 是有用的在數(shù)字受約束的工作母機(jī)中。 這些申請(qǐng)的大部分是公開 - 環(huán) ,但是雇用回應(yīng)環(huán)檢測(cè)受到驅(qū)策的成