外文翻譯--數(shù)控機床的核心及動力測量值的幾何誤差-數(shù)控設(shè)計-資料下載頁
2025-05-12 06:43本頁面
【導(dǎo)讀】系統(tǒng)，并且給出了一些實驗結(jié)果。這些實驗結(jié)果表明了一些靜態(tài)與動態(tài)誤差特性。通過關(guān)于在動態(tài)信號運動或暫停時的分析，會發(fā)現(xiàn)數(shù)控機床上一?？貦C床輪廓誤差的方法。然而，在這些標準中幾。乎所有的幾何誤差都是在靜態(tài)或類似靜態(tài)的情形下被測量出的。的軸被移動到特定的位置，停止轉(zhuǎn)動的時候被測量記錄的。涉系統(tǒng)的現(xiàn)代化測量系統(tǒng)提高了校準效率。調(diào)整校準部分程序和機械補償參數(shù)。但是他們也不能克服只能在靜態(tài)情況下測量的限制。器械的花費使得整個校準過程異常昂貴。眾所周知，一臺三軸機床有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，house-built數(shù)據(jù)收集和處理系統(tǒng)被使用。許多實驗表明，當機床已適當調(diào)整過后，最大誤差小于微米。線性軸間隔50毫米。這些隨機變化可稱為測量噪聲。器讀數(shù)誤差，工作臺傾斜引起的Abbe誤差，激光測量系統(tǒng)誤差，主軸振動等。球型金屬塊被廣泛使用于這項測試。數(shù)作為時間函數(shù)，來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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