Determination of the optimal servo feed speed by thermal model during multi-pulse discharge process of WEDM
Determination of the optimal servo feed speed by thermal model during multi-pulse discharge process of WEDM
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DOI：
10.1016/j.ijmecsci.2018.05.006
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发表时间：
2018-07
影响因子：
7.3
通讯作者：
Zhi Chen;Guojun Zhang;Han Fenglin;Yanming Zhang;Y. Rong
中科院分区：
文献类型：
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作者：
Zhi Chen;Guojun Zhang;Han Fenglin;Yanming Zhang;Y. Rong
在线放电加工（WEDM）中，当伺服进给速度与可达到的材料去除率不匹配时，会出现线电极回退和滞后现象，在实际加工过程中不利于加工效率和精度。本研究提出了一个热模型，用于预测多脉冲放电过程中的最佳伺服进给速度。首先，分析伺服进给速度对实际切削速度和放电状态的影响，确定最佳伺服进给速度。此外，在已有的热模型的基础上，考虑蒸发潜热，建立了修正的热模型来获得单脉冲放电过程中的放电坑尺寸，并且该修正模型比以往研究中的其他热模型具有更高的精度。然后，在单脉冲放电热模型的基础上，建立了热模型来获取多脉冲放电过程中可达到的材料去除率，验证的实验数据表明，预测可达到的材料去除率与最佳伺服进给速度吻合良好。最终根据不同伺服进给速度下的切割实验结果可以发现，最佳伺服进给速度比其他伺服进给速度下能够同时获得更快的实际切割速度和更窄的切缝宽度。
In wire electrical discharge machining (WEDM), the phenomena of wire electrode going back and hysteresis will appear when servo feed speed does not match the achievable material removal rate, and it is injurious to machining efficiency and accuracy in practical machining process. This study presents a thermal model for predicting the optimal servo feed speed during multi-pulse discharge process. Firstly, the effects of servo feed speed on the practical cutting speed and discharge state are analyzed to define the optimal servo feed speed. Additionally, based on previous thermal model and considering the latent heat of evaporation, a modified thermal model is established to obtain discharge crater size in single pulse discharge process, and this modified model is proved to be with higher precision than other thermal models in previous researches. Then, on the basis of single pulse discharge thermal model, a thermal model is developed to acquire achievable material removal rate in multi-pulse discharge process, and verified experiment data shows that the predicted achievable material removal rate agrees well with the optimal servo feed speed. Eventually, according to the results of cutting experiment under different servo feed speeds, it can be found that the optimal servo feed speed can simultaneously obtain the faster practical cutting speed and the narrower kerf width than those under the other servo feed speeds.