臺灣博碩士論文加值系統

在切削加工過程中發生刀具斷裂,對工件或工具機勢必會造成一定程
度的損傷.因此,於加工過程中對刀具斷裂的即時監控是重要的.而且,監控
系統的運作可幫助自動生產加工技術更加完善,增加競爭力. 本論文的
最終目標,是欲對於加工過程中對刀具斷裂的現象,發展出一套可廣用於
CNC工具機的智慧型監控系統.由於截至目前,還未有任一種感測技術或診
斷法則可使用於廣泛的加工條件或加工環境之下.因此本論文所提出的智
慧型監控系統,是以感測器融合(Sensor Fusion)的觀念做為感測技術,所
使用的感測對象有馬達電流,切削力與音洩訊號,其中馬達電流的感測技術
是本研究的主題之一.直接由感測訊號之大小型態通常難以判斷好壞,需要
有效可靠的分析方法做為輔助工具.吾人以小波轉換(wavelet transform)
方法分析所量測的切削力訊號,藉由轉換係數判斷刀具斷裂的發生.由吾人
的實驗結果顯示,馬達電流的變化可以判斷刀具斷裂的發生,而且使用 感
測器融合芳式可以更增強監控系統的判斷能力.小波轉換在對於切削力的
分析上,可以有效地顯現刀具斷裂的特徵,提供更多的資訊使監控系統作出
正確的判斷.

An effective tool breakage monitoring system can detect tool
breakageas early as possible to prevent irreparable damages of
workpiece and machinetool. And, for unmanned manufacturing
operations, in-process monitoring oftool breakage plays a
critically important role. The goal of this thesis is to
devolp an intelligent tool breakage monitoring system of a CNC
machine center. Because none of sensing anddiagnosis techniques
can assure reliable in practical operations, a sensorfusion
method was proposed. The cutting force signal, acoustic emission
signal and the motor current signal were used, the motor current
sensing techniques were the first part of this thesis. Because
it is hard to identifydirectly from these raw signals, the
second part of this thesis would examinethe feasibility of
extracting feature of tool breakage from wavelet transformof
cutting force signal. The experimental results show that the
ocurrence of tool breakage could be detected from the motor
current sensing. And thecoefficients of wavelet transform of
cutting force could be used to monitortool breakage.