放电诱导雾化烧蚀深型孔加工技术研究

Deep-type Hole Machining by Aerosol Dielectric EDM Ablation

为提高常规电火花深型孔加工的稳定性及工艺指标,提出了一种新的深型孔加工方法——放电诱导雾化烧蚀加工技术。采用"水基-氧气"高压气雾介质作为放电介质,对烧蚀燃烧反应具有冷却、抑制和分散放电作用,有效降低了烧蚀能量,保证了加工的平稳性。另外,放电间隙中分散的熔融金属与气雾介质的氧气继续充分燃烧,气雾介质吸收释放的能量而迅速气化,产生的爆炸效果对蚀除产物的排出有巨大的促进作用,蚀除产物呈现喷发式排出。因此,放电诱导雾化烧蚀深型孔加工技术不断引入了新的能量,并解决了排屑的难题。在本试验条件下,对于边长为4.4mm的方孔,加工深度可达70 mm以上,材料蚀除率约为内冲液电火花加工的5.45倍,电极质量相对损耗降低了82%。

A hole machining method to improve the stability and technological index for deep hole machining by electro-discharge machining（EDM） was proposed. The method employed continuous flushing and intermittent oxygen feeding（i.e., aerosol dielectric EDM ablation）. Aerosol,a mixture generated by oxygen and water,was used as the discharge dielectric to cool,restrain and disperse the ablation energy when the oxygen was supplied. That condition can effectively control the degree of ablation and stabilize the process. In addition,the erosion particles in the discharge gap continued to burn. Aerosol dielectric absorbed heat and gasified rapidly,which resulted in explosion. The erosion particles were removed from the machining area in the type of outbursts. Hence,the aerosol dielectric EDM ablation introduced new energy and solved the problem of chip removal. The hole with a side length of 4.4 mm can be machined successfully,and its depth can reach more than 70 mm under the experimental conditions. The machining efficiency was 5.45 times that of the EDM,and the relative tool wear ratio decreased by 82%.