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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/31839
標題: | 線切割放電加工機之即時監測系統開發 Development of the Real-Time Monitoring System for WEDM |
作者: | Pei-Chun Tung 董珮君 |
指導教授: | 廖運炫 |
關鍵字: | 線切割放電加工,放電延遲時間,即時監測系統, WEDM,ignition delay time,real-time monitoring system, |
出版年 : | 2006 |
學位: | 碩士 |
摘要: | 本論文針對線切割放電加工機開發出一波形即時監測系統,於加工時即時顯示放電延遲時間分佈圖。此系統先將原始間隙電壓、電流波形整為方波,接著由89C52單晶片估算出放電延遲時間後,依放電延遲時間之有無,將放電波形鑑別為正常波與不正常波兩類。此系統除可顯示不正常波百分比與擷取1000次放電所需時間外,尚能由使用者自行決定某特定放電延遲時間長度,並顯示放電延遲時間小於及大於此特定長度之正常波百分比。最後利用本論文開發之系統,觀察線切割放電加工機在不同加工參數下加工時,放電延遲時間的變化趨勢。當進给速率愈快及短路停機前,放電延遲時間分佈圖有向左偏的趨勢;伺服電壓愈高及斷線前,放電延遲時間分佈圖有向右偏的趨勢,這些放電延遲時間的變化趨勢都可以由放電現象得到合理的解釋。 A WEDM ignition delay time monitoring system which can display the distribution of the ignition delay time on a real-time basis is developed in this research. The discharge pulse trains of the gap voltage and the gap current in WEDM process are rectified into square waveforms respectively before they are sent into the 89C52 microcontroller, the major component of the system, for data processing. Based on length of the delay time, the discharge pulse is categorized into two groups – the normal discharges and the abnormal discharges. After every 1000 discharges, the distribution of the ignition delay time, the percentages of the normal discharges and abnormal discharges, and the time consumed for 1000 discharges just recorded are displayed instantly on the LCD panel of the system. The normal discharges can be further divided into two sub-groups according to the specific reference ignition delay-time value set by the user. The respective percentages of the two sub-groups are also presented on the LCD panel. To verify the system, the distribution tendency of the delay time is observed under various machining conditions. It shows that the distribution is skew more to the left when the feed rate is increased or before the WEDM machine shut down itself due to frequent occurrence of short circuit discharges. On the other hand, the distribution is skew less to the left when the servo voltage is increased or when the wire breaking is about to take place. Both the tendencies are reasonable and explainable by the physical mechanism of WEDM. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/31839 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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