本文選題：鈦合金　切入點：電火花加工　出處：《機(jī)械工程學(xué)報》2017年21期

【摘要】：在大面積鈦合金電火花加工過程中,容易造成電蝕產(chǎn)物聚集且不易冷卻從而產(chǎn)生集中放電、拉弧及短路現(xiàn)象,嚴(yán)重的甚至?xí)䶮齻ぜ谋砻妗Ｒ虼?為了實現(xiàn)持續(xù)穩(wěn)定的正�；鸹ǚ烹�,在放電過程中放電點的位置分布必須均勻。電火花放電產(chǎn)生的氣泡及加工屑是影響放電點分布均勻性的關(guān)鍵因素。為此,首先通過計算流體動力學(xué)軟件Fluent對氣泡的運動規(guī)律進(jìn)行了仿真分析,然后通過高速攝像機(jī)拍攝透明電極下氣泡的運動規(guī)律驗證仿真的可靠性。結(jié)果表明氣泡在間隙內(nèi)的運動經(jīng)過了膨脹、收縮及破裂的過程。通過試驗對脈沖放電產(chǎn)生的加工屑顆粒的直徑分布及數(shù)量進(jìn)行了研究,并對加工屑在放電瞬間的拋撒機(jī)理做出了合理的假設(shè),建立了電火花加工過程中放電間隙流場的氣液固混合相三維模型,仿真分析了氣泡運動對加工屑運動的影響規(guī)律。研究發(fā)現(xiàn)加工屑在氣泡內(nèi)部時,由于空氣對加工屑的阻力小于工作液對氣泡膨脹的阻力,加工屑快速向氣泡的邊界靠近。而當(dāng)加工屑穿透氣泡的邊界進(jìn)入工作液中后其速度迅速降低,且隨著氣泡的收縮逐漸靠近放電發(fā)生的位置。因此可以通過改變脈沖間隔實現(xiàn)控制氣泡的大小及加工屑的分布,從而可以有效避免集中放電提高放電點分布的均勻性。
[Abstract]:In the process of large area titanium alloy EDM, it is easy to cause electrical corrosion products to gather and not to be cooled, resulting in concentrated discharge, arc pulling and short circuit phenomena, which may even burn the surface of the workpiece seriously. In order to realize the continuous and stable normal spark discharge, the location distribution of the discharge point must be uniform during the discharge process. The bubble produced by the electric spark discharge and the processing chip are the key factors affecting the uniformity of the discharge point distribution. Firstly, the motion law of the bubble is simulated and analyzed by the computational fluid dynamics software Fluent. The simulation results show that the bubble motion in the gap has expanded. The process of shrinkage and rupture. The diameter distribution and quantity of machining chip particles produced by pulse discharge are studied through experiments, and reasonable assumptions are made on the throwing mechanism of machining chips at the moment of discharge. A three-dimensional model of gas-liquid-solid mixed phase in discharge gap flow field during EDM is established, and the effect of bubble motion on chip motion is simulated and analyzed. Because the air resistance to the processing debris is smaller than that of the working fluid to the bubble expansion, the processing debris is rapidly approaching the bubble boundary, and the velocity decreases rapidly when the cutting debris penetrates the boundary of the bubble into the working fluid. As the bubble shrinks closer to the position where the discharge occurs, the size of the bubble and the distribution of the chip can be controlled by changing the pulse interval, which can effectively avoid the concentrated discharge to improve the uniformity of the discharge point distribution.
【作者單位】： 西安交通大學(xué)機(jī)械制造系統(tǒng)工程國家重點實驗室;
【基金】：陜西省工業(yè)攻關(guān)資助項目(2014K06-03)
【分類號】：TG661
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本文編號：1658293