焊(han)接操(cao)作機點(dian)(dian)(dian)焊(han)是依靠(kao)被焊(han)工(gong)件接觸(chu)面(mian)之間形(xing)成(cheng)的焊(han)點(dian)(dian)(dian)、將工(gong)件連(lian)接起來的電(dian)阻焊(han)方法。按(an)一次(ci)形(xing)成(cheng)的焊(han)點(dian)(dian)(dian)數，可分為單點(dian)(dian)(dian)焊(han)和多(duo)點(dian)(dian)(dian)焊(han)；按(an)對焊(han)件的供電(dian)方向，可分為單面(mian)點(dian)(dian)(dian)焊(han)和雙面(mian)點(dian)(dian)(dian)焊(han)等。

常見的點(dian)焊(han)(han)方法(fa)是(shi)雙面點(dian)焊(han)(han)(電極從工件兩側(ce)供電)，的場合。點(dian)焊(han)(han)接(jie)(jie)頭的尺寸可參考(kao)表3．8．1大(da)致確定，常用金屬材料的焊(han)(han)接(jie)(jie)點(dian)距(ju)見表3．8．2。

點焊是(shi)一種高速、經濟的(de)連接方法，適(shi)用(yong)于制造可裝配成搭接接頭、接頭無(wu)密封(feng)性要求的(de)薄(bo)板構件(jian)(jian)，如汽車(che)駕駛(shi)室、轎(jiao)車(che)車(che)身、 長機機翼、儀表(biao)殼體，也可用(yong)于焊接建筑用(yong)鋼筋、電器元件(jian)(jian)引線、家用(yong)電器等。

通(tong)用(yong)焊(han)(han)機(ji)(ji)可焊(han)(han)接(jie)多(duo)種不同厚度和(he)形(xing)(xing)狀的(de)(de)工(gong)件(jian)，專用(yong)焊(han)(han)機(ji)(ji)則用(yong)于焊(han)(han)接(jie)形(xing)(xing)狀、尺寸(cun)、厚度、材質接(jie)近的(de)(de)類型的(de)(de)工(gong)件(jian)。中大功(gong)率焊(han)(han)機(ji)(ji)重量大，一般都(dou)固定安(an)裝。小型焊(han)(han)接(jie)操(cao)作機(ji)(ji)外形(xing)(xing)復雜(za)或尺寸(cun)較大的(de)(de)薄壁工(gong)件(jian)時，工(gong)件(jian)通(tong)常不動(dong)而使焊(han)(han)接(jie)機(ji)(ji)(焊(han)(han)鉗)相對工(gong)件(jian)移動(dong)。

絕大多(duo)數通用(yong)點(dian)焊(han)(han)機采用(yong)雙面饋電，可用(yong)于焊(han)(han)接(jie)多(duo)種尺寸和形(xing)狀(zhuang)、多(duo)類金屬材料的工件(jian)，通常一次焊(han)(han)接(jie)循環(huan)獲得一個焊(han)(han)點(dian)。單面點(dian)焊(han)(han)可提(ti)生(sheng)產率，減小焊(han)(han)接(jie)變形(xing)，并(bing)可從(cong)單面接(jie)近某些(xie)可達性(xing)差的焊(han)(han)件(jian)。

直(zhi)壓式(shi)(shi)焊機(ji)的下電(dian)極(ji)通常固定不動(dong)(dong)，而(er)上電(dian)極(ji)沿(yan)垂直(zhi)方向(xiang)作直(zhi)線運動(dong)(dong)。電(dian)極(ji)壓力通過(guo)氣缸或油缸帶動(dong)(dong)電(dian)極(ji)施加(jia)于(yu)工件(jian)。通用(yong)(yong)直(zhi)壓式(shi)(shi)焊機(ji)大多數(shu)采用(yong)(yong)氣動(dong)(dong)加(jia)壓系統，既能用(yong)(yong)于(yu)點焊也(ye)能用(yong)(yong)于(yu)凸焊(圖3．8．12)。點焊機(ji)的管伸長度一般較大，而(er)凸焊機(ji)的臂伸長度都很(hen)小(因剛度要求(qiu)(qiu)高(gao))。此(ci)外，焊接機(ji)器人凸焊機(ji)要求(qiu)(qiu)加(jia)壓機(ji)構的隨動(dong)(dong)性(xing)要好(hao)，因而(er)均采用(yong)(yong)滾動(dong)(dong)導軌、小質量活塞和(he)蝶形彈(dan)簧緩(huan)沖等措施，以提高(gao)電(dian)極(ji)運動(dong)(dong)部分的跟隨性(xing)。