劃線(xian)平板找正(zheng)方法與劃線(xian)基準 :毛坯(pi)劃(hua)(hua)線的(de)時候(hou),一般只(zhi)用(yong)(yong)三只(zhi)千(qian)斤頂(ding)頂(ding)上,把毛胚找(zhao)正(zheng),原則是為了(le)確(que)保不加工(gong)(gong)面(mian)與加工(gong)(gong)面(mian)中間各(ge)點的(de)距離相同,應(ying)該將不加工(gong)(gong)面(mian)用(yong)(yong)劃(hua)(hua)線盤找(zhao)平,或者(zhe)把不加工(gong)(gong)面(mian)用(yong)(yong)直角尺找(zhao)垂直,如果(guo)有幾個(ge)不加工(gong)(gong)面(mian)時,應(ying)該以面(mian)積 大 的那個不(bu)加工面找正(zheng),并且照顧其他(ta)不(bu)加工表面, 使各處壁厚盡量均勻,孔與輪轂或凸臺盡量同心(xin)。 對于很多孔的箱體,要照顧(gu)各(ge)孔毛坯(pi)和凸臺,使(shi)各(ge)個孔均有加(jia)工余(yu)量而且(qie)盡量與凸臺同心(xin)。 在光坯(pi)(pi)上劃線(xian)(xian)時,工(gong)件與(yu)劃線(xian)(xian)平(ping)臺的接(jie)觸面(mian)(mian),應是已加(jia)工(gong)的基(ji)準(zhun)面(mian)(mian),不存(cun)在向毛坯(pi)(pi)劃線(xian)(xian)那樣的找正問題。光坯(pi)(pi)劃線(xian)(xian)應以(yi)加(jia)工(gong)的設計(ji)基(ji)準(zhun)作為(wei)劃線(xian)(xian)。基(ji)準(zhun)。以(yi)兩(liang)(liang)個互相垂直的平(ping)面(mian)(mian)為(wei)基(ji)準(zhun)。以(yi)一個平(ping)面(mian)(mian)與(yu)一個中心(xin)平(ping)面(mian)(mian)為(wei)基(ji)準(zhun)。以(yi)兩(liang)(liang)個互相垂直的中心(xin)平(ping)面(mian)(mian)為(wei)基(ji)準(zhun)