聲射訊號應用於砂輪堵塞與工件表面粗糙度之監控

Application of Acoustic Emission on Monitoring of Chip Loading and Surface Roughness for Grinding

吳侑璋(You-Jhang Wu)

指導教授 ： 蔡曜陽

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201602433

摘要

磨削是以砂輪磨粒進行材料移除，其提供良好精密與表面粗糙度，而黏屑會堵塞砂輪孔洞與磨料刃邊影響磨削能力，因此需即時判斷修整之時機，維持砂輪磨削能力與加工物之良好表面粗糙度。
本研究為一種監控砂輪磨削狀態之系統，透過砂輪在磨削材料所產生內部結構變化之聲能，以能量響應偵測砂輪表面與孔洞的黏屑狀態，達到加工物表面粗糙度的控制。藉由傅立葉轉換之頻率響應特定區間內可偵測到黏屑填補與脫落之趨勢，以反應黏屑之狀態進而預測表面粗糙度，提供在微細加工方面避免加工物燒傷以及監控品質上。
本研究利用磨削參數探討黏屑情況進而預測工件的表面粗糙度，將黏屑狀態存在砂輪表面分為三個部分，第一部分為響應上升區，其代表黏屑填補砂輪孔洞直到趨近於平面，其保有良好表面粗糙度；第二部分為響應驟降區，其代表黏屑首次脫落，則砂輪表面逐漸凹凸不平；第三部分為響應低點區，則為黏屑持續脫落導致砂輪表面惡化進而影響工件的表面粗糙度，經實驗驗證，磨削參數改變黏屑區域然後影響工件的表面粗糙度。
透過劃分能量響應區域能夠判別黏屑區域與砂輪填塞之情形以達到監控砂輪狀態之目的，偵測到能量響應低點處則進行砂輪修整，成功達到控制表面粗糙度之品質監控。

關鍵字

聲射訊號 ； 修整 ； 平面研磨 ； 表面粗糙度 ； 堵塞

並列摘要

Grinding processing is an important part of precision machining. Grinding technology provided fine precision and surface roughness. Grinding is used abrasive grain to removal material; however, chip loading clogged the pores of grinding wheel and edge of abrasive to affect ability of grinding, so immediate dress is necessary to maintain fine surface roughness of workpiece.
The purpose of this study was to monitor the state of grinding wheel by acoustic energy of changed structure from grinding materials, detecting the state of chip loading of wheel surface and pore to control the surface roughness of workpiece.
The method used in this paper was to detect trend of chip loading fill and drop by magnitude of spectrum, to reflect state of chip loading and predict surface roughness, this method provided to avoid the burns and monitor the quality for workpiece.
This study investigated the state of chip loading with grinding parameter to predict surface roughness of workpiece. The results of the experiment indicated that the chip loading status divided into three parts; the first part was magnitude rise area that was chip loading filled pores in the wheel until close to the plane, workpiece maintain good surface roughness; the second part was magnitude fall area that was chip loading dropping first, this phenomenon made surface of grinding wheel rugged; the third part was low magnitude area that was chip loading continually dropping deteriorate surface of wheel and affecting the roughness of workpiece surface. The experiment verified grinding parameters change chip loading region and affect the workpiece surface roughness.
The findings of the research have led to the conclusion that acoustic emission signal was transformed by Fast Fourier Transform, this method can be determined area of chip loading and situation of grinding wheel loading in order to achieve to monitor grinding. When the magnitude of spectrum reach the low range, grinding wheel is going to dress. This method has been successfully controlling the quality of the surface roughness.

並列關鍵字

acoustic emission ； dressing ； surface grinding ； surface roughness ； chip loading

參考文獻

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