一、火花機的主要組成部件
火花機也稱為(wei)電(dian)火(huo)花加(jia)工機(ji)(ji)床或EDM機(ji)(ji)床,主要組成部(bu)件包括以下(xia)幾個部(bu)分:
1、機床主體
機(ji)床主體是火花機(ji)的基礎結構,它承載著所有的工(gong)作部件和控制系統。主體通常(chang)由(you)鑄鐵或(huo)鋼材制成,以確保穩定性(xing)和剛性(xing)。
2、主軸和電極夾持裝置
主軸是安裝和移動電極的部分,用于將電極精確定位在工件上方。電極夾持裝置用于(yu)固(gu)定(ding)電極,并(bing)確保電極在加工過程中保持穩定(ding)的位置和角(jiao)度。
3、工作臺和工件夾持裝置
工作臺用于支撐和移動工件,以便在加工過程中精確定位工件。工(gong)件(jian)夾(jia)持裝(zhuang)置用于固定工(gong)件(jian),防止在加工(gong)過(guo)程中(zhong)發生(sheng)移(yi)動(dong)或振(zhen)動(dong)。
4、電源和控制系統
電源系統為火花機提供所需的電壓和電流,用于產生電火花。控制(zhi)系(xi)統是(shi)火花機的(de)核心部分(fen),它控制(zhi)電(dian)極和(he)工作臺的(de)運動,以(yi)及(ji)電(dian)源的(de)通(tong)(tong)斷(duan),確(que)保(bao)加工過程的(de)精確(que)性和(he)穩定性。控制(zhi)系(xi)統通(tong)(tong)常(chang)包括計算機數控(CNC)系(xi)統,用于(yu)編程和(he)自動化加工過程。
5、工作液循環系統
工作液在火花(hua)加工過(guo)程中起到冷(leng)卻(que)、潤滑和清除加工廢屑的作用。工作液循環系統負責將(jiang)工作液輸送到加工區域,并回收和過(guo)濾使用過(guo)的工作液。
6、電氣系統和傳感器
電氣系統為火花機提供電力和信號傳輸,確保各個部件的正常運行。傳感器用于(yu)監測加(jia)工過(guo)程中的各種參數(shu),如(ru)電(dian)極和(he)工作(zuo)臺的位(wei)置、電(dian)流和(he)電(dian)壓(ya)等,以便(bian)及時調整和(he)控制加(jia)工過(guo)程。
7、安全防護裝置
火花機在工(gong)作過(guo)程中可(ke)能會產生(sheng)火花和飛濺物(wu),因此需要(yao)配備(bei)安(an)全防(fang)(fang)(fang)護(hu)裝置,如防(fang)(fang)(fang)護(hu)罩、防(fang)(fang)(fang)護(hu)門(men)和緊急停機按鈕(niu)等,以保護(hu)操作人員的安(an)全。
二、火花機的工作原理
進行電火花機加工(gong)(gong)(gong)(gong)時(shi),工(gong)(gong)(gong)(gong)具電(dian)極(ji)(ji)和工(gong)(gong)(gong)(gong)件分別接(jie)脈沖電(dian)源的兩(liang)極(ji)(ji),并(bing)浸入工(gong)(gong)(gong)(gong)作(zuo)液中,或將(jiang)(jiang)工(gong)(gong)(gong)(gong)作(zuo)液充(chong)入放電(dian)間(jian)隙。通過(guo)間(jian)隙自動控制(zhi)系統控制(zhi)工(gong)(gong)(gong)(gong)具電(dian)極(ji)(ji)向工(gong)(gong)(gong)(gong)件進給,當兩(liang)電(dian)極(ji)(ji)間(jian)的間(jian)隙達(da)到一(yi)定距離(li)時(shi),兩(liang)電(dian)極(ji)(ji)上施加的脈沖電(dian)壓(ya)將(jiang)(jiang)工(gong)(gong)(gong)(gong)作(zuo)液擊穿,產生火花(hua)放電(dian)。
在放電(dian)(dian)的微細通道中瞬時集中大量的熱能,溫度(du)可高達(da)一萬攝氏度(du)以上,壓力也有(you)急劇變化,從而(er)使(shi)這(zhe)(zhe)一點工(gong)作(zuo)表(biao)面(mian)局部微量的金屬材料立刻熔化、氣(qi)化,并爆炸(zha)式地飛濺(jian)到(dao)工(gong)作(zuo)液(ye)中,迅速冷凝,形成固體的金屬微粒,被工(gong)作(zuo)液(ye)帶走。這(zhe)(zhe)時在工(gong)件(jian)表(biao)面(mian)上便(bian)留下一個(ge)微小的凹坑痕(hen)跡,放電(dian)(dian)短暫(zan)停歇,兩電(dian)(dian)極(ji)間工(gong)作(zuo)液(ye)恢復(fu)絕緣狀態(tai)。
緊接著,下一(yi)個脈(mo)沖(chong)電(dian)壓又在兩電(dian)極相對接近的另一(yi)點(dian)處擊穿,產生(sheng)火花(hua)放(fang)電(dian),重復上(shang)述過程。這樣,雖然每(mei)個脈(mo)沖(chong)放(fang)電(dian)蝕(shi)除的金屬(shu)量(liang)極少,但(dan)因每(mei)秒有成(cheng)千上(shang)萬次脈(mo)沖(chong)放(fang)電(dian)作(zuo)用(yong),就能蝕(shi)除較(jiao)多的金屬(shu),具(ju)有一(yi)定的生(sheng)產率。
在(zai)保持工(gong)具(ju)(ju)電(dian)極(ji)(ji)與(yu)(yu)工(gong)件(jian)(jian)之(zhi)間(jian)恒(heng)定放電(dian)間(jian)隙的(de)(de)條件(jian)(jian)下,一(yi)邊蝕(shi)除工(gong)件(jian)(jian)金(jin)屬,一(yi)邊使工(gong)具(ju)(ju)電(dian)極(ji)(ji)不斷地(di)向工(gong)件(jian)(jian)進給,最(zui)后便(bian)加工(gong)出與(yu)(yu)工(gong)具(ju)(ju)電(dian)極(ji)(ji)形狀相(xiang)對(dui)(dui)應的(de)(de)形狀來。因此,只要改(gai)變工(gong)具(ju)(ju)電(dian)極(ji)(ji)的(de)(de)形狀和工(gong)具(ju)(ju)電(dian)極(ji)(ji)與(yu)(yu)工(gong)件(jian)(jian)之(zhi)間(jian)的(de)(de)相(xiang)對(dui)(dui)運動(dong)方式,就能加工(gong)出各種復(fu)雜(za)的(de)(de)型面(mian)。工(gong)具(ju)(ju)電(dian)極(ji)(ji)常(chang)用導電(dian)性良好、熔點(dian)較高、易(yi)加工(gong)的(de)(de)耐電(dian)蝕(shi)材(cai)料,如銅(tong)、石墨、銅(tong)鎢合金(jin)和鉬等。在(zai)加工(gong)過程(cheng)中,工(gong)具(ju)(ju)電(dian)極(ji)(ji)也有(you)損耗,但小于工(gong)件(jian)(jian)金(jin)屬的(de)(de)蝕(shi)除量,甚(shen)至接近于無(wu)損耗。
工(gong)作(zuo)液作(zuo)為(wei)放(fang)電(dian)(dian)(dian)(dian)介質(zhi),在加工(gong)過(guo)程(cheng)中還起著冷卻(que)、排屑等作(zuo)用。常用的(de)(de)(de)(de)工(gong)作(zuo)液是粘度較低、閃點(dian)較高、性(xing)能(neng)穩定(ding)的(de)(de)(de)(de)介質(zhi),如(ru)煤油、去離子水和乳化液等。電(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)機是一種(zhong)自激放(fang)電(dian)(dian)(dian)(dian),其特(te)點(dian)如(ru)下:火(huo)(huo)花(hua)放(fang)電(dian)(dian)(dian)(dian)的(de)(de)(de)(de)兩(liang)(liang)個電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)間(jian)(jian)在放(fang)電(dian)(dian)(dian)(dian)前具較高的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓,當兩(liang)(liang)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)接(jie)近(jin)時(shi),其間(jian)(jian)介質(zhi)被擊穿后(hou),隨即(ji)發生(sheng)火(huo)(huo)花(hua)放(fang)電(dian)(dian)(dian)(dian)。伴隨擊穿過(guo)程(cheng),兩(liang)(liang)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)間(jian)(jian)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)阻(zu)急(ji)劇變小,兩(liang)(liang)極(ji)(ji)(ji)之(zhi)(zhi)間(jian)(jian)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)壓也隨之(zhi)(zhi)急(ji)劇變低。火(huo)(huo)花(hua)通(tong)(tong)道必(bi)須在維(wei)持暫短的(de)(de)(de)(de)時(shi)間(jian)(jian)(通(tong)(tong)常為(wei)10-7-10-3s)后(hou)及(ji)時(shi)熄滅,才可(ke)保持火(huo)(huo)花(hua)放(fang)電(dian)(dian)(dian)(dian)的(de)(de)(de)(de)“冷極(ji)(ji)(ji)”特(te)性(xing)(即(ji)通(tong)(tong)道能(neng)量轉換的(de)(de)(de)(de)熱能(neng)來不及(ji)傳至(zhi)電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)縱深),使通(tong)(tong)道能(neng)量作(zuo)用于極(ji)(ji)(ji)小范圍。通(tong)(tong)道能(neng)量的(de)(de)(de)(de)作(zuo)用,可(ke)使電(dian)(dian)(dian)(dian)極(ji)(ji)(ji)局部被腐蝕(shi)。利用火(huo)(huo)花(hua)放(fang)電(dian)(dian)(dian)(dian)時(shi)產生(sheng)的(de)(de)(de)(de)腐蝕(shi)現(xian)象(xiang)對(dui)材料(liao)進行尺(chi)寸加工(gong)的(de)(de)(de)(de)方法,叫電(dian)(dian)(dian)(dian)火(huo)(huo)花(hua)機加工(gong)。