擠出吹塑模主要由兩半陰模構成，一般由模體、模頸、模腔、切坯套、截坯口、導柱等組成，對于模具結構設計主要有如下要求

(1) 模具(ju)分型(xing)面設計(ji)的要求

擠出(chu)吹(chui)(chui)(chui)塑模(mo)(mo)具(ju)的(de)結(jie)構設計(ji)模(mo)(mo)具(ju)分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)位(wei)(wei)置(zhi)(zhi)(zhi)選擇(ze)應(ying)(ying)使模(mo)(mo)具(ju)對稱，減(jian)(jian)小(xiao)吹(chui)(chui)(chui)脹比(bi)，易(yi)于制品(pin)(pin)脫(tuo)(tuo)模(mo)(mo)。因此，分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)的(de)位(wei)(wei)置(zhi)(zhi)(zhi)通常由吹(chui)(chui)(chui)塑制品(pin)(pin)模(mo)(mo)腔的(de)形(xing)(xing)狀(zhuang)確(que)定。大多(duo)數(shu)吹(chui)(chui)(chui)塑模(mo)(mo)具(ju)是設計(ji)成以分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)為(wei)界相配合的(de)兩個(ge)半模(mo)(mo)，對于形(xing)(xing)狀(zhuang)不(bu)(bu)規(gui)則(ze)的(de)瓶類和(he)容器(qi)(qi)，分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)位(wei)(wei)置(zhi)(zhi)(zhi)的(de)確(que)定特別重(zhong)要(yao)(yao)，如位(wei)(wei)置(zhi)(zhi)(zhi)不(bu)(bu)當將導致產品(pin)(pin)無(wu)法脫(tuo)(tuo)模(mo)(mo)或造成瓶體(ti)劃傷(shang)。這時，需要(yao)(yao)用不(bu)(bu)規(gui)則(ze)分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)的(de)模(mo)(mo)具(ju)，有時甚(shen)至(zhi)要(yao)(yao)使用三個(ge)或更(geng)多(duo)的(de)可(ke)移動部件組成的(de)多(duo)分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)模(mo)(mo)具(ju)，利(li)于產品(pin)(pin)脫(tuo)(tuo)模(mo)(mo)。對橫截面(mian)(mian)(mian)(mian)(mian)(mian)(mian)為(wei)圓形(xing)(xing)的(de)容器(qi)(qi)，分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)通過(guo)直徑設置(zhi)(zhi)(zhi);對橢(tuo)(tuo)圓形(xing)(xing)容器(qi)(qi)，分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)應(ying)(ying)通過(guo)橢(tuo)(tuo)圓形(xing)(xing)的(de)長(chang)軸;矩形(xing)(xing)容積的(de)分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)可(ke)通過(guo)中心線(xian)或對角線(xian)，其中后者可(ke)減(jian)(jian)小(xiao)吹(chui)(chui)(chui)脹比(bi)，但(dan)與(yu)分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)相對的(de)拐角部位(wei)(wei)壁(bi)厚較小(xiao)。對有些制品(pin)(pin)，則(ze)需要(yao)(yao)設置(zhi)(zhi)(zhi)多(duo)個(ge)分(fen)(fen)(fen)(fen)(fen)(fen)型(xing)(xing)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)。容器(qi)(qi)把(ba)(ba)(ba)手(shou)應(ying)(ying)沿分(fen)(fen)(fen)(fen)(fen)(fen)模(mo)(mo)面(mian)(mian)(mian)(mian)(mian)(mian)(mian)設置(zhi)(zhi)(zhi)。把(ba)(ba)(ba)手(shou)的(de)橫截面(mian)(mian)(mian)(mian)(mian)(mian)(mian)應(ying)(ying)呈方形(xing)(xing)，拐角用圓弧過(guo)渡，優化(hua)壁(bi)厚分(fen)(fen)(fen)(fen)(fen)(fen)布。把(ba)(ba)(ba)手(shou)孔一般采(cai)用嵌塊來成型(xing)(xing)。還可(ke)用注射(she)法單獨成型(xing)(xing)把(ba)(ba)(ba)手(shou)。

(2)型腔的設計要求(qiu)

吹(chui)(chui)(chui)塑模(mo)(mo)(mo)(mo)具(ju)(ju)(ju)型(xing)(xing)腔(qiang)直接確定制(zhi)品(pin)的(de)(de)形(xing)狀(zhuang)(zhuang)、尺寸與外(wai)觀(guan)性能(neng)。用(yong)于PE吹(chui)(chui)(chui)塑的(de)(de)模(mo)(mo)(mo)(mo)具(ju)(ju)(ju)型(xing)(xing)腔(qiang)表(biao)(biao)面(mian)(mian)應稍(shao)微有點粗(cu)(cu)糙(cao)(cao)。否則，會(hui)造成(cheng)(cheng)模(mo)(mo)(mo)(mo)具(ju)(ju)(ju)型(xing)(xing)腔(qiang)排氣不(bu)(bu)良，夾(jia)留有氣泡(pao)，使制(zhi)品(pin)出(chu)現“橘皮紋”的(de)(de)表(biao)(biao)面(mian)(mian)缺陷。還會(hui)導致制(zhi)品(pin)的(de)(de)冷卻(que)速率低且不(bu)(bu)均勻(yun)，使制(zhi)品(pin)各處的(de)(de)收縮率不(bu)(bu)一樣。由于PE吹(chui)(chui)(chui)塑模(mo)(mo)(mo)(mo)具(ju)(ju)(ju)的(de)(de)溫度較低，加上型(xing)(xing)坯(pi)吹(chui)(chui)(chui)脹壓力較小，吹(chui)(chui)(chui)脹的(de)(de)型(xing)(xing)坯(pi)不(bu)(bu)會(hui)楔人粗(cu)(cu)糙(cao)(cao)型(xing)(xing)腔(qiang)表(biao)(biao)面(mian)(mian)的(de)(de)波谷，而(er)是位于或(huo)跨過波峰，這(zhe)樣，可(ke)(ke)保證制(zhi)品(pin)有光(guang)(guang)滑的(de)(de)表(biao)(biao)面(mian)(mian)，并提供微小的(de)(de)網狀(zhuang)(zhuang)通道，使模(mo)(mo)(mo)(mo)腔(qiang)易于排氣。對(dui)模(mo)(mo)(mo)(mo)腔(qiang)做噴砂(sha)處理(li)(li)可(ke)(ke)形(xing)成(cheng)(cheng)粗(cu)(cu)糙(cao)(cao)的(de)(de)表(biao)(biao)面(mian)(mian)。噴砂(sha)粒度要(yao)適當，對(dui)HDPE的(de)(de)吹(chui)(chui)(chui)塑模(mo)(mo)(mo)(mo)具(ju)(ju)(ju)，可(ke)(ke)采用(yong)較粗(cu)(cu)的(de)(de)粒度，LDPE要(yao)采用(yong)較細的(de)(de)粒度。蝕刻(ke)模(mo)(mo)(mo)(mo)腔(qiang)也(ye)可(ke)(ke)形(xing)成(cheng)(cheng)粗(cu)(cu)糙(cao)(cao)的(de)(de)表(biao)(biao)面(mian)(mian)，還可(ke)(ke)在制(zhi)品(pin)表(biao)(biao)面(mian)(mian)形(xing)成(cheng)(cheng)花紋。吹(chui)(chui)(chui)塑高(gao)透(tou)明(ming)或(huo)高(gao)光(guang)(guang)澤性容器(尤其采用(yong)PET、PVC或(huo)PP)時，要(yao)拋(pao)光(guang)(guang)模(mo)(mo)(mo)(mo)腔(qiang)。對(dui)工程(cheng)塑料的(de)(de)吹(chui)(chui)(chui)塑，模(mo)(mo)(mo)(mo)具(ju)(ju)(ju)型(xing)(xing)腔(qiang)一般不(bu)(bu)能(neng)噴砂(sha)，除(chu)可(ke)(ke)蝕刻(ke)出(chu)花紋外(wai)，還可(ke)(ke)經(jing)拋(pao)光(guang)(guang)或(huo)消光(guang)(guang)處理(li)(li)。

模具型腔(qiang)的(de)(de)尺(chi)寸主(zhu)要(yao)由制(zhi)品(pin)的(de)(de)外(wai)形尺(chi)寸并(bing)同時考慮制(zhi)品(pin)的(de)(de)收(shou)(shou)縮率(lv)(lv)來確定。收(shou)(shou)縮率(lv)(lv)一般是(shi)(shi)指室溫(22℃)下模腔(qiang)尺(chi)寸與(yu)成(cheng)型24h后制(zhi)品(pin)尺(chi)之間的(de)(de)差異。如HDPE瓶的(de)(de)吹塑成(cheng)型其收(shou)(shou)縮率(lv)(lv)的(de)(de)80％～90％是(shi)(shi)在成(cheng)型后的(de)(de)24h內發生的(de)(de)。