外文翻譯--數(shù)控機(jī)床的核心及動(dòng)力測(cè)量值的幾何誤差-數(shù)控設(shè)計(jì)-資料下載頁(yè)
【導(dǎo)讀】系統(tǒng)，并且給出了一些實(shí)驗(yàn)結(jié)果。這些實(shí)驗(yàn)結(jié)果表明了一些靜態(tài)與動(dòng)態(tài)誤差特性。通過(guò)關(guān)于在動(dòng)態(tài)信號(hào)運(yùn)動(dòng)或暫停時(shí)的分析，會(huì)發(fā)現(xiàn)數(shù)控機(jī)床上一。控機(jī)床輪廓誤差的方法。然而，在這些標(biāo)準(zhǔn)中幾。乎所有的幾何誤差都是在靜態(tài)或類似靜態(tài)的情形下被測(cè)量出的。的軸被移動(dòng)到特定的位置，停止轉(zhuǎn)動(dòng)的時(shí)候被測(cè)量記錄的。涉系統(tǒng)的現(xiàn)代化測(cè)量系統(tǒng)提高了校準(zhǔn)效率。調(diào)整校準(zhǔn)部分程序和機(jī)械補(bǔ)償參數(shù)。但是他們也不能克服只能在靜態(tài)情況下測(cè)量的限制。器械的花費(fèi)使得整個(gè)校準(zhǔn)過(guò)程異常昂貴。眾所周知，一臺(tái)三軸機(jī)床有21處可能出現(xiàn)幾何誤差的。它是惠普激光系統(tǒng)的5倍速度。同時(shí)，house-built數(shù)據(jù)收集和處理系統(tǒng)被使用。許多實(shí)驗(yàn)表明，當(dāng)機(jī)床已適當(dāng)調(diào)整過(guò)后，最大誤差小于微米。線性軸間隔50毫米。這些隨機(jī)變化可稱為測(cè)量噪聲。器讀數(shù)誤差，工作臺(tái)傾斜引起的Abbe誤差，激光測(cè)量系統(tǒng)誤差，主軸振動(dòng)等。球型金屬塊被廣泛使用于這項(xiàng)測(cè)試。數(shù)作為時(shí)間函數(shù)，來(lái)獲得任何形狀的輪廓誤差。
【正文】 tion, it stops for one or two seconds and then is traveling back to 0mm position. This procedure with different moving speeds is repeated several times and an obvious jump error of about two micrometers is observed repeatedly. From these experiments, it is also observed that the jump error has nearly nothing to do with the speed of the moving table. This error is mainly caused by the initial table angular readjustment induced by dynamic forces. The results of both angular and straightness measurements also show obviously an angular jump in horizontal direction at the return point when the table moves forth and back. As there is a gap between the slides, especially in horizontal direction, the direction of the dynamic force induces a table tilt in the opposite direction and produces an Abbe error jump. Contouring errors It is well known that circular tests provide a rapid and efficient way of measuring a machine tool39。s contouring accuracy along a circular contour. Circular contours provide one of the best checks for contouring performance in that as a machine is traversing with multiple axes along a circular trajectory each axis goes through sinusoidal acceleration, velocity, and position changes. So in all standards for evaluating CNC machines, circular contour test is a key part. A Ball bar is widely used for this purpose. Other devices and instruments include circular masks, cross grid encoders. Here, we use our developed dynamic measurement system to get any shape of contour errors by using the direct x and y encoder readings as a function of time. is an example of the circular contouring error. The imperfect movement of CNC machines When the table is driven to a desired position, for example, to the 100mm position along the x direction and then back without a dwell time, the table actually does not reach the point of 100mm. The experiments also showed that offset between the actual position and the ideal position get bigger when the speed of moving table is getting higher. A control mode of dwell time with a few milseconds can make the table be in the desired position. 4. CONCLUSIONS Static and dynamic machine tool geometric errors were performed using a mercially available laser interferometer system and a housebuilt data collecting and processing system. The experiment results showed some significant differences between the static and dynamic error characteristics. Along with the expected increase in measurement noise, which results from many error resources of machine tools, some other errors like jump error from back and forth movements of CNC machine axis are observed, which makes it necessary to measure and evaluate the dynamic characteristics of machine tools.
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