進行電(dian)火花加(jia)(jia)工時，工具電(dian)極和工件分別接脈沖(chong)電(dian)源的兩(liang)極，并(bing)浸入工作液(ye)(ye)中，或(huo)將工作液(ye)(ye)充入放(fang)電(dian)間(jian)(jian)隙。通過間(jian)(jian)隙自動(dong)控制(zhi)系統控制(zhi)工具電(dian)極向工件進給(gei)，當兩(liang)電(dian)極間(jian)(jian)的間(jian)(jian)隙達(da)到一定距離時，兩(liang)電(dian)極上施加(jia)(jia)的脈沖(chong)電(dian)壓將工作液(ye)(ye)擊穿，產生火花放(fang)電(dian)。

在放電(dian)的(de)微(wei)細(xi)通道中瞬時集(ji)中大量的(de)熱(re)能，溫度可高達10000℃以上，壓力也有急劇變(bian)化(hua)，從而(er)使這一點工(gong)(gong)作(zuo)(zuo)表(biao)面局部微(wei)量的(de)金屬(shu)材料立刻(ke)熔化(hua)、氣化(hua)，并(bing)爆炸式地飛(fei)濺(jian)到工(gong)(gong)作(zuo)(zuo)液中，迅速冷凝，形成固體的(de)金屬(shu)微(wei)粒，被工(gong)(gong)作(zuo)(zuo)液帶走。這時在工(gong)(gong)件表(biao)面上便留下(xia)一個微(wei)小的(de)凹坑痕跡(ji)，放電(dian)短暫停歇，兩電(dian)極間工(gong)(gong)作(zuo)(zuo)液恢復絕(jue)緣狀態。

緊接著，下一個脈(mo)沖電壓又在兩電極相對接近的(de)(de)另一點處擊穿(chuan)，產(chan)生火(huo)花放電，重復上(shang)述過(guo)程(cheng)。這樣(yang)，雖然每個脈(mo)沖放電蝕(shi)除的(de)(de)金屬量極少，但因每秒有成千上(shang)萬次脈(mo)沖放電作(zuo)用，就能蝕(shi)除較多的(de)(de)金屬，具有一定的(de)(de)生產(chan)率。

在保持工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)與(yu)工(gong)件(jian)之(zhi)間恒定放電(dian)(dian)間隙的(de)條件(jian)下，一邊(bian)蝕(shi)除工(gong)件(jian)金屬(shu)，一邊(bian)使工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)不斷地向工(gong)件(jian)進給，最后(hou)便加(jia)工(gong)出與(yu)工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)形狀(zhuang)相對應(ying)的(de)形狀(zhuang)來(lai)。因(yin)此，只(zhi)要(yao)改(gai)變工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)的(de)形狀(zhuang)和工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)與(yu)工(gong)件(jian)之(zhi)間的(de)相對運動方(fang)式，就能加(jia)工(gong)出各種復(fu)雜(za)的(de)型面。工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)常用導(dao)電(dian)(dian)性良好、熔點較(jiao)高、易加(jia)工(gong)的(de)耐(nai)電(dian)(dian)蝕(shi)材(cai)料(liao)，如(ru)銅(tong)、石墨、銅(tong)鎢合(he)金和鉬等(deng)。在加(jia)工(gong)過程中，工(gong)具(ju)(ju)電(dian)(dian)極(ji)(ji)(ji)也有(you)損耗(hao)，但小于工(gong)件(jian)金屬(shu)的(de)蝕(shi)除量，甚至接(jie)近于無(wu)損耗(hao)。

工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)作(zuo)(zuo)液(ye)作(zuo)(zuo)為放(fang)電(dian)(dian)(dian)(dian)(dian)介(jie)(jie)質(zhi)(zhi)(zhi)，在(zai)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)過程中還起著冷(leng)卻(que)、排屑等作(zuo)(zuo)用(yong)。常用(yong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)作(zuo)(zuo)液(ye)是粘度較低(di)(di)、閃點(dian)較高(gao)、性能(neng)(neng)穩定的(de)(de)(de)(de)(de)(de)(de)(de)(de)介(jie)(jie)質(zhi)(zhi)(zhi)，如煤油、去離子(zi)水和乳化(hua)液(ye)等。電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)機是一種自激放(fang)電(dian)(dian)(dian)(dian)(dian)，其(qi)特點(dian)如下： 火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)兩(liang)個電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)間(jian)在(zai)放(fang)電(dian)(dian)(dian)(dian)(dian)前具較高(gao)的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，當兩(liang)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)接近時(shi)，其(qi)間(jian)介(jie)(jie)質(zhi)(zhi)(zhi)被擊穿(chuan)后，隨(sui)即發生(sheng)(sheng)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)。伴隨(sui)擊穿(chuan)過程，兩(liang)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)間(jian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)阻急劇變(bian)(bian)(bian)小(xiao)(xiao)，兩(liang)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)之(zhi)間(jian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)也隨(sui)之(zhi)急劇變(bian)(bian)(bian)低(di)(di)。火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)通道(dao)必須在(zai)維持暫短的(de)(de)(de)(de)(de)(de)(de)(de)(de)時(shi)間(jian)（通常為10-7-10-3s）后及(ji)時(shi)熄(xi)滅，才可保持火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)(de)(de)“冷(leng)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)”特性（即通道(dao)能(neng)(neng)量轉(zhuan)換的(de)(de)(de)(de)(de)(de)(de)(de)(de)熱能(neng)(neng)來不及(ji)傳至電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)縱深），使(shi)通道(dao)能(neng)(neng)量作(zuo)(zuo)用(yong)于極(ji)(ji)(ji)(ji)(ji)(ji)(ji)小(xiao)(xiao)范(fan)圍(wei)。通道(dao)能(neng)(neng)量的(de)(de)(de)(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用(yong)，可使(shi)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)局(ju)部被腐蝕。 利用(yong)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)時(shi)產(chan)(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)(de)腐蝕現(xian)(xian)象對材(cai)料進(jin)(jin)行尺(chi)寸加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)方法，叫電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)。 電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)是在(zai)較低(di)(di)的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)范(fan)圍(wei)內(nei)，在(zai)液(ye)體介(jie)(jie)質(zhi)(zhi)(zhi)中的(de)(de)(de)(de)(de)(de)(de)(de)(de)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)放(fang)電(dian)(dian)(dian)(dian)(dian)。 電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)的(de)(de)(de)(de)(de)(de)(de)(de)(de)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong) 按照工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)具電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)(de)(de)(de)(de)(de)形(xing)(xing)式及(ji)其(qi)與工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)(jian)之(zhi)間(jian)相對運動(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)特征，可將電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)方式分為五(wu)類：利用(yong)成(cheng)型工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)具電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)，相對工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)(jian)作(zuo)(zuo)簡單進(jin)(jin)給運動(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)成(cheng)形(xing)(xing)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)；利用(yong)軸向移動(dong)(dong)(dong)的(de)(de)(de)(de)(de)(de)(de)(de)(de)金屬絲(si)作(zuo)(zuo)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)具電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)，工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)(jian)按所(suo)需形(xing)(xing)狀(zhuang)和尺(chi)寸作(zuo)(zuo)軌跡運動(dong)(dong)(dong)，以切割導電(dian)(dian)(dian)(dian)(dian)材(cai)料的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)線切割加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)；利用(yong)金屬絲(si)或(huo)成(cheng)形(xing)(xing)導電(dian)(dian)(dian)(dian)(dian)磨(mo)輪作(zuo)(zuo)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)具電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)，進(jin)(jin)行小(xiao)(xiao)孔磨(mo)削或(huo)成(cheng)形(xing)(xing)磨(mo)削的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)磨(mo)削；用(yong)于加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)螺(luo)紋環規、螺(luo)紋塞規、齒輪等的(de)(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)共軛(e)回轉(zhuan)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)；小(xiao)(xiao)孔加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)、刻(ke)英表(biao)面合金化(hua)、表(biao)面強化(hua)等其(qi)他(ta)種類的(de)(de)(de)(de)(de)(de)(de)(de)(de)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)。電(dian)(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)(hua)(hua)(hua)(hua)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)能(neng)(neng)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)普通切削加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)方法難以切削的(de)(de)(de)(de)(de)(de)(de)(de)(de)材(cai)料和復雜形(xing)(xing)狀(zhuang)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)(jian)；加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)時(shi)無(wu)切削力(li)；不產(chan)(chan)生(sheng)(sheng)毛刺和刀痕溝紋等缺陷；工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)具電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)(ji)(ji)材(cai)料無(wu)須比工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)件(jian)(jian)材(cai)料硬(ying)；直接使(shi)用(yong)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)，便于實現(xian)(xian)自動(dong)(dong)(dong)化(hua)；加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)后表(biao)面產(chan)(chan)生(sheng)(sheng)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)層(ceng)，在(zai)某些應用(yong)中須進(jin)(jin)一步去除；工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)作(zuo)(zuo)液(ye)的(de)(de)(de)(de)(de)(de)(de)(de)(de)凈化(hua)和加(jia)(jia)工(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)(gong)中產(chan)(chan)生(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)(de)(de)煙霧(wu)污染處理比較麻煩。