外文翻譯---電火花線切割工藝進(jìn)給率的控制-全文預(yù)覽
【正文】 ieving stable machining under the condition where there exists an unexpected disturbance during machining。The proportion of short circuits(short ratio)and the sparking frequency can be used to monitor and evaluate the gap condition。As shown in ，the feed rate is controlled at a predetermined value when the gap state is determined as an open circuit or a normal spark，and at the other predetermined value when the gap state is determined as an arc discharge or a short circuit，the former feed rate is shorter than the latter。So it should be avoided。These are open circuit，normal spark，arc discharge and short circuit。 Besides，tm of a normal spark is visibly shorter than that of an open circuit。tm is a time duration when Qm remains high。Ql，Qm and Qh are output states of the parators。The PCI1240 card connected to the PCI bus and municated with the Pentium PC through a dual port random access memory(RAM)with the capacity of 8K words is used to count the pulse trains by software written in C language。A plex programmable logic device(CPLD)，which allows easy modification of the design，clocked by a 4MHz crystal oscillator is not only employed to generate the pulse control signals( and P2)，it is also used to discriminate the gap states。Those are gap states examination module and motion control module。 Today the feed rate control is carried out via the analysis of the abovementioned process parameters。 The time interval ends with reaching a reference voltage or a reference current。The gap conditions at spark erosion are ideal if the voltage breakdown occurs after a short ignition delay。The gap voltage was directly proportional to the working gap width。Feed rate control and the process parametersThe quality of feed rate control determines the stability of the gap width the machining process。 presented an adaptive control system to online optimize the sparking frequency by estimating the workpiece height with a multiinput model。Wire breakage and unstable machining drastically reduce the machining efficiency and accuracy in wireEDM。In order to improve the machining efficiency，stability and quality，many efforts have been made by the researchers and manufacturers to develop pulse discrimination and control system。附 錄英文原文Feed rate control of the wireEDM processIntroductionThe CNC wireEDM machines first appears in the market in the 1970s，Although the wireEDM process has been playing an important role in the tooling and manufacturing industry，especially for the production of punches and dies，The metal removal process o
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