在實踐中,常常由於對控製點缺乏正確理解,而產生種種錯誤。為引起重視,做到正確設置,現將常見問題及處置意見分述如下:
(1)控製點必須能夠定量表達
kongzhidiandezhiliangtexingbixunenggoudingliangbiaoda,cainengquedingkongzhidiandingliangdezhiliangmubiaozhi,yibianquerenkongzhidianshifoudadaolekongzhiyaoqiu。ruguozhiliangtexingshidingxingbiaodade,yeyingshefazhuanhuaweidingliangbiaoda。liru,ruochanpindemifengxingnenglieweikongzhidian,zegaizhiliangtexingbunengdingxingdiguiding:“不許滲油、漏油”,而應規定定量的衡量指標。
(2)控製點的設置單位
以什麼為單位來設置控製點,是實踐中經常遇到的問題。這要根據具體情況采取不同的處理方法:
①大批、大量生產的過程應以質量特性為單位設置控製點。在大批、daliangshengchandetiaojianxia,yigekongzhidianzhikongzhiyigezhiliangtexing,erbushiyiguochengweidanweishezhikongzhidian,yinweiyidaoguochengwangwangchanshengduogezhiliangtexing,danyingxianggegezhiliangtexingdeyinsuwangwangbujinxiangtong,qiduiyingdekongzhixiangmuneirongdangranyehuisuizhierbianhua。shishikongzhishiguochengzhiliangkongzhidegongzuoneirong,ruzhenduiduogezhiliangtexingjianlikongzhixiangmu,bujinshikongzhixiangmufuzahua,erqierongyihunxiao“質量特性 ― 影響因素 ― 控製項目”的因果關係,不利於質量分析與控製。因此,在大批、大量生產情況下,應以質量特性為單位設置控製點。
② 單件、小批生產允許以過程為單位設置控製點。單件、小(xiao)批(pi)生(sheng)產(chan)因(yin)產(chan)品(pin)千(qian)差(cha)萬(wan)別(bie),產(chan)量(liang)又(you)小(xiao),若(ruo)仍(reng)以(yi)產(chan)品(pin)質(zhi)量(liang)特(te)性(xing)為(wei)單(dan)位(wei)設(she)置(zhi)控(kong)製(zhi)點(dian)就(jiu)必(bi)然(ran)使(shi)控(kong)製(zhi)點(dian)數(shu)量(liang)過(guo)多(duo),而(er)且(qie)還(hai)經(jing)常(chang)發(fa)生(sheng)變(bian)化(hua),使(shi)過(guo)程(cheng)質(zhi)量(liang)控(kong)製(zhi)和(he)管(guan)理(li)過(guo)於(yu)繁(fan)雜(za)。然(ran)而(er)單(dan)件(jian)、小批生產,雖然產品千差萬別,但產品多屬同一類型,常常有相同的關鍵過程和大致相同的主導性因素,故在單件、小批生產的條件下,可以某些關鍵過程為對象設置控製點。
③duopinzhonglunfanshengchan,keangongtongdezhiliangtexingshezhikongzhidian。duopinzhonglunfanshengchandechanpin,qijiegoujibenxiangtong,jinchicunguigeyousuobutongeryingxiangyinsuzechangchangshixiangtongde,qishengchanpiliangyibanyebijiaoda。zaizhezhongqingkuangxia,jiukeangongtongdezhiliangtexingshezhikongzhidian。danruoguigexiangchahenda,yizhizaigongyishangheyingxiangyinsushangyoujiaodaqubie,zelingdangbielun。
(3)三種類型的控製點
質量控製點的對象,一般多理解為專指產品的質量特性,其實它有三種不同的類型:
①以產品質量特性為對象設置的控製點。這是最常見的情況,但在實踐中,它並不是唯一類型。
②以過程的質量特性(即工藝參數)weiduixiangshezhidekongzhidian。ruzhuzaotieshuidejiaozhuwendu,tabushichanpindezhiliangtexing,danqueshibaozhengchanpinzhiliangdebiyaotiaojian,yizhegegongyicanshuweiduixiangshezhikongzhidian,shizhichuyuwendingzhuangtai,cainengbaozhengzhujiandezhiliang。
③以輔助材料的質量特性為對象而設置的控製點,如型砂的透氣性、水分、強度等特性,它既不是產品的質量特性,也不是過程的質量特性(工藝參數),而是輔助材料的質量特性。以型砂的質量特性為對象設置控製點,使之處於穩定狀態,才能保證造型和鑄件的質量。
手機版






