Experimental results
The following figures show some of the results obtained. As expected, there is no useful
information in the signals if the sensor is applied to either the honing spindle or the machining table,
as those positions seem to be too far away from the honing process. Therefore, a deeper look is only
taken at the results for the other two sensor positions, namely on top and on the side of the work-piece
fixture. Figure 3 shows the results of the two positions for the force-controlled honing process. Every
figure contains the measured acoustic emission signal, the oscillation movement as an indicator for the
honing process, the spectrogram and the FFT of the acoustic emission signal. The sensor supplies two
different levels of the output signal depending on the position. The signals measured on top of the
fixture show approximately ten-times higher values for the FFT amplitude than those measured on the
side. In this regard, the y-axis for the acoustic emission signal and for the FFT of the acoustic emission
signal have been adjusted to obtain a better overview. As the acoustic emission and the oscillation
movement show, each figure correlates to one honing process. The FFT shows in both cases a clear
peak at approximately 5 Hz. As the oscillation movement of the honed parts has been conducted with
an oscillation velocity of 2.0 m/s and an oscillation length of 40 mm, a peak at 2.5 Hz would have
been expected. However, there is only a very small peak at that position; the peak for the double
frequency is much bigger. This could be due to deviations in the cylinder form of the honed parts. The
honing stone would meet those deviations twice during an oscillation movement and thus lead to the
higher frequency. The deviations of the cylinder form were measured and showed values of up to
13μm. This could be a possible explanation for this effect. The further peaks seem to be the harmonic
waves belonging to the original peak. The signals do not, however, show a significant peak at 10 Hz
which would be the correlating frequency to the rotation speed. The work pieces in both cases have a
good roundness being lower than 3μm before the honing process. This explains why this frequency
cannot be detected due to the continuous movement of the tool. The honing improves the roundness
slightly to values below 2.5μm. The spectrogram shows lighter areas in the vicinity of the dead centers
of the oscillation movements. This seems to indicate less material removal due to the smaller cutting
velocities which even come to zero at the dead ends for the oscillation portion. The same is true for the
beginning of the honing process when the honing stone is not yet in the phase of high removal rates or
did not yet even reach the bore wall during the first steps. While the results seem to be similar for both
sensor positions, there is one significant difference. If the amplitudes of the FFT are compared, it can
be seen that the amplitude for the sensor position on top of the work piece fixture is approximately ten
times higher than for the position on the side of the fixture. This could be expected, as on top of the
fixture the sensor is much closer to the process.
ผลการทดลองตัวเลขต่อไปนี้แสดงบางส่วนของผลลัพธ์ที่ได้ ตามที่คาดไว้ มีไม่มีประโยชน์ข้อมูลในสัญญาณถ้าเซ็นเซอร์ที่ใช้กับแกนสร้างเสริมหรือโต๊ะจักรเป็นตำแหน่งที่ดูเหมือน จะไกลเกินไปจากกระบวนการสร้างเสริม ดังนั้น ดูลึกเป็นเท่านั้นผลลัพธ์สำหรับเซนเซอร์สองตำแหน่งอื่น ๆ คือด้านบน และด้านข้าง ของ ชิ้นงานการแข่งขัน รูปที่ 3 แสดงผลของสองตำแหน่งสำหรับควบคุมบังคับให้กระบวนการสร้างเสริม ทุกรูปประกอบด้วยสัญญาณปล่อยเสียงวัด การเคลื่อนไหวสั่นเป็นตัวบ่งชี้สำหรับการเครื่องมืออุปกรณ์กระบวนการ การแสงแยกสี และ FFT ของสัญญาณปล่อยเสียง อุปกรณ์เซนเซอร์สองระดับที่แตกต่างของสัญญาณขึ้นอยู่กับตำแหน่ง สัญญาณที่วัดจากการสูงประมาณสิบ - เวลาแข่งขันแสดงค่าสำหรับคลื่น FFT กว่าวัดด้านข้าง ในเรื่องนี้ แกน y สำหรับสัญญาณเสียงปล่อย และ FFT ของมลพิษเสียงมีการปรับสัญญาณการรับภาพรวมดีขึ้น มลพิษเสียงและการสั่นการเคลื่อนไหวแสดง แต่ละรูปคู่กับกระบวนการสร้างเสริมที่หนึ่ง FFT แสดงในทั้งสองกรณีชัดเจนสูงสุดที่ประมาณ 5 Hz เป็นการสั่น เคลื่อนไหว honed ส่วนที่มีการดำเนินกับการสั่นความเร็ว 2.0 m/s และความยาวสั่น 40 มม. สูงสุดที่ 2.5 Hz จะมีbeen expected. However, there is only a very small peak at that position; the peak for the doublefrequency is much bigger. This could be due to deviations in the cylinder form of the honed parts. Thehoning stone would meet those deviations twice during an oscillation movement and thus lead to thehigher frequency. The deviations of the cylinder form were measured and showed values of up to13μm. This could be a possible explanation for this effect. The further peaks seem to be the harmonicwaves belonging to the original peak. The signals do not, however, show a significant peak at 10 Hzwhich would be the correlating frequency to the rotation speed. The work pieces in both cases have agood roundness being lower than 3μm before the honing process. This explains why this frequencycannot be detected due to the continuous movement of the tool. The honing improves the roundnessslightly to values below 2.5μm. The spectrogram shows lighter areas in the vicinity of the dead centersof the oscillation movements. This seems to indicate less material removal due to the smaller cuttingvelocities which even come to zero at the dead ends for the oscillation portion. The same is true for thebeginning of the honing process when the honing stone is not yet in the phase of high removal rates ordid not yet even reach the bore wall during the first steps. While the results seem to be similar for bothsensor positions, there is one significant difference. If the amplitudes of the FFT are compared, it can
be seen that the amplitude for the sensor position on top of the work piece fixture is approximately ten
times higher than for the position on the side of the fixture. This could be expected, as on top of the
fixture the sensor is much closer to the process.
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