Micro-EDM of micro-stepped hole in YG8 cemented carbide by using micro milling cutter
Micro-EDM of micro-stepped hole in YG8 cemented carbide by using micro milling cutter
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DOI：
10.1007/s00170-022-09268-z
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发表时间：
2022-05
期刊：
影响因子：
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通讯作者：
Bin Xu;Tao Feng;Yong Xiao;Xiao-yu Wu;L. Fu;Hang Zhao;Jianguo Lei;Chun-yang Zhao
中科院分区：
文献类型：
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作者：
Bin Xu;Tao Feng;Yong Xiao;Xiao-yu Wu;L. Fu;Hang Zhao;Jianguo Lei;Chun-yang Zhao
微台阶孔在微电机、精密模具、医疗器械等领域有着广泛的应用。YG8硬质合金因其硬度高、耐磨性好而被广泛用于加工微台阶孔。然而，YG8硬质合金微步进孔的高质量加工难以通过车削和铣削来实现。微细电火花加工不受宏观切削力的限制，不受材料硬度的限制，是加工超硬材料微结构的主流技术。针对上述问题，本文提出了采用微细电火花加工微细阶梯孔的方法。首先，利用高速旋转的微细铣刀对YG8硬质合金进行微细电火花加工，得到微小孔的基本结构。在微细电火花加工过程中，由于磨损，导致了微细铣刀长度的减小。其次，利用带长度磨损的微细铣刀作为工具电极，围绕基本微小孔的中心轴线摆动，对YG8硬质合金进行微细电火花加工，在基本微小孔上加工二次基本微小孔，形成微台阶孔。在加工二次基本微小孔的过程中，无磨损的微细铣刀会产生与基本微小孔深度相同的二次基本微小孔，不会形成微台阶孔。本文将微细铣刀在长度方向上的磨损转化为有利因素。通过摆动微细铣刀，在电火花加工的不同阶段使用相同的微细铣刀加工出微步进孔。通过大量的加工实验，对主要工艺参数进行了优化，并对实验结果进行了分析。最后，在转速为2000转、加工电压为90 V、占空比为0.5的条件下，用直径为400µm的微细铣刀对YG8硬质合金进行了微细电火花加工，得到了质量较好的微步进孔。
Micro-stepped holes have been widely used in the fields of micro motor, precision mold, medical device, and so on. YG8 cemented carbide is widely used for machining micro-stepped hole because of its high hardness and good wear resistance. However, it is difficult to realize high-quality machining of micro-stepped holes on YG8 cemented carbide by turning and milling. Micro-EDM has no macroscopic cutting force and is not limited by material hardness, so it is the mainstream technology for machining microstructures on superhard materials. To address the above problems, the paper proposed to adopt micro-EDM to process the micro-stepped hole by using a micro milling cutter. Firstly, micro-EDM was carried out on YG8 cemented carbide with a high-speed rotating micro milling cutter to obtain the basic micro-hole structure. In the process of micro-EDM, the length of micro milling cutter was reduced due to wear. Secondly, micro-EDM was performed on the YG8 cemented carbide using the micro milling cutter with wear in length as the tool electrode, which was made to shake around the central axis of the basic micro-hole, so that a secondary basic micro-hole was machined on the basic micro-hole and a micro-stepped hole was formed. In the process of machining the secondary basic micro-hole, micro milling cutter with no wear would produce a secondary basic micro-hole with the same depth as the basic micro-hole, and no micro-stepped hole would be formed. In this paper, the wear of micro milling cutter in the length direction was transformed into a favorable factor. With the micro milling cutter shaking, a micro-stepped hole was obtained using the same micro milling cutter in different stages of EDM. Through a large number of machining experiments, the main process parameters were optimized and the experimental results were analyzed in this paper. Finally, the micro-EDM of YG8 cemented carbide was carried out with a micro milling cutter with a diameter of 400 µm at 2000 RPM rotational speedn, 90 V machining voltageV, and 0.5 duty ratioR, and a micro-stepped hole with good quality was obtained.