精密鑄造中的(de)鑄造方法選擇(ze)的(de)原則有哪些：

1．優先采(cai)用(yong)砂(sha)型(xing)(xing)(xing)(xing)精密(mi)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)。據統(tong)計，我(wo)國或(huo)是(shi)國際上，在全部鑄(zhu)(zhu)(zhu)(zhu)(zhu)件產量(liang)中(zhong)，60～70％的(de)(de)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件是(shi)用(yong)砂(sha)型(xing)(xing)(xing)(xing)生(sheng)(sheng)產的(de)(de)，而且其(qi)中(zhong)70％左(zuo)右是(shi)用(yong)粘土(tu)(tu)砂(sha)型(xing)(xing)(xing)(xing)生(sheng)(sheng)產的(de)(de)。主要(yao)原(yuan)因是(shi)砂(sha)型(xing)(xing)(xing)(xing)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)較(jiao)之(zhi)其(qi)它(ta)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)方法成(cheng)本低、生(sheng)(sheng)產工(gong)藝(yi)(yi)簡(jian)單(dan)、生(sheng)(sheng)產周期短(duan)。所(suo)(suo)以(yi)象汽車的(de)(de)發動機(ji)氣缸(gang)體、氣缸(gang)蓋、曲(qu)軸等(deng)(deng)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件都是(shi)用(yong)粘土(tu)(tu)濕型(xing)(xing)(xing)(xing)砂(sha)工(gong)藝(yi)(yi)生(sheng)(sheng)產的(de)(de)。當濕型(xing)(xing)(xing)(xing)不能滿足(zu)要(yao)求時再考慮(lv)使用(yong)粘土(tu)(tu)砂(sha)表干砂(sha)型(xing)(xing)(xing)(xing)、干砂(sha)型(xing)(xing)(xing)(xing)或(huo)其(qi)它(ta)砂(sha)型(xing)(xing)(xing)(xing)。粘土(tu)(tu)濕型(xing)(xing)(xing)(xing)砂(sha)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)的(de)(de)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件重量(liang)可(ke)從幾(ji)公斤直到幾(ji)十公斤，而粘土(tu)(tu)干型(xing)(xing)(xing)(xing)生(sheng)(sheng)產的(de)(de)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件可(ke)重達幾(ji)十噸。一般來講，對于(yu)中(zhong)、大型(xing)(xing)(xing)(xing)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件，鑄(zhu)(zhu)(zhu)(zhu)(zhu)鐵件可(ke)以(yi)用(yong)樹(shu)脂自硬砂(sha)型(xing)(xing)(xing)(xing)、鑄(zhu)(zhu)(zhu)(zhu)(zhu)鋼件可(ke)以(yi)用(yong)水玻璃砂(sha)型(xing)(xing)(xing)(xing)來生(sheng)(sheng)產，可(ke)以(yi)獲得尺(chi)寸(cun)精確、表面光(guang)潔(jie)的(de)(de)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件，但(dan)成(cheng)本較(jiao)高。當然，砂(sha)型(xing)(xing)(xing)(xing)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)生(sheng)(sheng)產的(de)(de)鑄(zhu)(zhu)(zhu)(zhu)(zhu)件精度、表面光(guang)潔(jie)度、材(cai)質的(de)(de)密(mi)度和金相(xiang)組(zu)織(zhi)、機(ji)械性能等(deng)(deng)方面往往較(jiao)差，所(suo)(suo)以(yi)當鑄(zhu)(zhu)(zhu)(zhu)(zhu)件的(de)(de)這些(xie)性能要(yao)求更高時，應該采(cai)用(yong)其(qi)它(ta)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)方法，例如熔(rong)模（失臘）鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)、壓(ya)鑄(zhu)(zhu)(zhu)(zhu)(zhu)、低壓(ya)鑄(zhu)(zhu)(zhu)(zhu)(zhu)造(zao)等(deng)(deng)等(deng)(deng)。

2．低壓(ya)鑄(zhu)造(zao)(zao)(zao)(zao)(zao)、壓(ya)鑄(zhu)、離心鑄(zhu)造(zao)(zao)(zao)(zao)(zao)等(deng)鑄(zhu)造(zao)(zao)(zao)(zao)(zao)方法，因(yin)設(she)備和(he)模(mo)具的價格昂貴(gui)，適(shi)合批(pi)量生(sheng)(sheng)產(chan)。對(dui)于(yu)小型(xing)鑄(zhu)件(jian)，可(ke)以采用(yong)(yong)水(shui)平分型(xing)或垂直分型(xing)的無(wu)箱高(gao)壓(ya)造(zao)(zao)(zao)(zao)(zao)型(xing)機生(sheng)(sheng)產(chan)線(xian)、實型(xing)造(zao)(zao)(zao)(zao)(zao)型(xing)生(sheng)(sheng)產(chan)效(xiao)率(lv)又高(gao)，占地面積也少(shao)；對(dui)于(yu)中件(jian)可(ke)選用(yong)(yong)各種有箱高(gao)壓(ya)造(zao)(zao)(zao)(zao)(zao)型(xing)機生(sheng)(sheng)產(chan)線(xian)、氣(qi)沖造(zao)(zao)(zao)(zao)(zao)型(xing)線(xian)，以適(shi)應快速、高(gao)精度造(zao)(zao)(zao)(zao)(zao)型(xing)生(sheng)(sheng)產(chan)線(xian)的要(yao)求，造(zao)(zao)(zao)(zao)(zao)芯(xin)方法可(ke)選用(yong)(yong)：冷芯(xin)盒(he)、熱芯(xin)盒(he)、殼芯(xin)等(deng)高(gao)效(xiao)制(zhi)芯(xin)方法。中等(deng)批(pi)量的大型(xing)鑄(zhu)件(jian)可(ke)以考慮應用(yong)(yong)樹(shu)脂自硬(ying)砂(sha)造(zao)(zao)(zao)(zao)(zao)型(xing)和(he)造(zao)(zao)(zao)(zao)(zao)芯(xin)。

單件(jian)小批(pi)生(sheng)產的重型(xing)(xing)(xing)(xing)鑄件(jian)，手工造(zao)型(xing)(xing)(xing)(xing)仍是(shi)重要(yao)的方法(fa)，手工造(zao)型(xing)(xing)(xing)(xing)能(neng)適(shi)應各種復雜的要(yao)求(qiu)比較靈活，不要(yao)求(qiu)很(hen)多工藝裝備。可以應用(yong)水玻(bo)璃砂(sha)型(xing)(xing)(xing)(xing)、VRH法(fa)水玻(bo)璃砂(sha)型(xing)(xing)(xing)(xing)、有機酯水玻(bo)璃自硬(ying)砂(sha)型(xing)(xing)(xing)(xing)、粘土干型(xing)(xing)(xing)(xing)、樹脂自硬(ying)砂(sha)型(xing)(xing)(xing)(xing)及水泥砂(sha)型(xing)(xing)(xing)(xing)等；對(dui)于單件(jian)生(sheng)產的重型(xing)(xing)(xing)(xing)鑄件(jian)，采用(yong)地(di)坑造(zao)型(xing)(xing)(xing)(xing)法(fa)成本低(di)，投(tou)產快。批(pi)量生(sheng)產或長期(qi)生(sheng)產的定型(xing)(xing)(xing)(xing)產品(pin)采用(yong)多箱(xiang)造(zao)型(xing)(xing)(xing)(xing)、劈箱(xiang)造(zao)型(xing)(xing)(xing)(xing)法(fa)比較適(shi)宜，雖然模具、砂(sha)箱(xiang)等開始(shi)投(tou)資高，但可從節(jie)約造(zao)型(xing)(xing)(xing)(xing)工時、提高產品(pin)質(zhi)量方面(mian)得到補(bu)償(chang)。