【正文】 O（聚苯醚）、NORYL（改性聚苯醚）、PPS（聚苯硫醚）、PSF（聚砜）、PC（聚碳酸脂）、PET（聚對苯二甲酸乙二醇脂）、PBT（聚對苯二甲酸丁二醇脂）、聚芳酯、聚芳砜；（7） 纖維素塑料；（8） 聚如：TPU胺酯， 這種分類方法，可以幫助理解塑料的性能，因為同一種分子結(jié)構(gòu)的材料有很多共性。雖然我國塑料模具在數(shù)量、質(zhì)量、技術(shù)等方面有了很大進步，但與國民經(jīng)濟發(fā)展的需求和世界先進水平相比，差距仍很大，一些大型、復(fù)雜、長壽命的高檔塑料模具每年仍需大量進口。有專家預(yù)測，在未來的模具市場中，塑料模具在模具總量中的比例將步提高，其發(fā)展速度將高于其他模具。有關(guān)數(shù)據(jù)表明，目前僅汽車行業(yè)就需要各種塑料制品36萬噸；電冰箱、洗衣機和空調(diào)的年產(chǎn)量均超過1000萬臺；彩電的年產(chǎn)量已超過3000萬臺。塑料,在各個領(lǐng)域、各個行業(yè)乃至國民經(jīng)濟中已擁有舉足輕重的不可替代的地位。同時出現(xiàn)了多品種高性能的工程塑料。做出了突破性的進展，取得第一個熱固性樹脂──酚醛樹脂的專利權(quán)。 oblique post drawing cores。之后，設(shè)計推出機構(gòu)。對塑料知識了解之后，根據(jù)給定零件的形狀尺寸、公差精度，結(jié)合塑件材料選擇成型方式為注塑。. After learning some knowledge of plastic, we choose the injector depend on the shape and the dimensional tolerances of the work piece, choose two cavities in one mold, choose XSZY250 injector by the volume of the plastic work piece. Design the shot means is depend on the plastic’s characteristic, and adopt the edge gate. Calculate the size of the cores and the cavity, the structure of drawing cores used oblique post is to be adopted. Design the ejector framework and choose the standard mold bases. Then design the relationship of the other work piece in the whole mold.Validate is the last thing. Validate the guide pin size and the shot capacity, injection pressure, open daylight of the injector. And the relation of the mold shut height with the injector size, so the design is over.Key Words：plastic injection mold。1872年在美國紐瓦克建廠生產(chǎn)。主要用于電器、儀表、機械和汽車工業(yè)。如聚甲醛、聚碳酸酯、ABS樹酯、聚苯醚、聚酰亞胺等。在2004年，塑料模具在整個模具行業(yè)中所占比例已上升到30％左右，未來幾年中，塑料模具還將保持較高速度發(fā)展。汽車工業(yè)近年來增長速度驚人，因此汽車模具潛在市場巨大。 塑料的特點（1） 質(zhì)量輕，比重小，最小為TPX，；最大的為聚氟乙烯，（2） 比強度高，有很多種塑料的比強度超過鋼材（3） 不溶于水，耐化學(xué)腐蝕，耐酸，耐堿。有的透明如玻璃，也有不透明的；有的非常柔軟，耐折迭，有類橡膠彈性；也有硬質(zhì)的，象ABS，機械性能優(yōu)良，可以做工程材料。注塑性能：PVC為無定形高聚物，沒有明顯的熔點，一般加熱到120℃～145℃就能熔化，但150℃以下就能分解出HCL氣體；180℃就大量的分解成HCL氣體；因此，需加入大量的熱穩(wěn)定劑才能注塑，注塑溫度的可調(diào)區(qū)間較小。具有占地面積小，模具裝拆方便，嵌件安裝容易，自料斗落入物料能較均勻地進行塑化，易實現(xiàn)自動化及多臺機自動線管理等優(yōu)點。因此，注塞式結(jié)構(gòu)不宜用于加工流動性差、熱敏性強的塑料。立式注射成形機和直角式注射成形機的結(jié)構(gòu)為注塞式結(jié)構(gòu)，而臥式注射成形機的結(jié)構(gòu)多為螺桿式，因此，此塑件應(yīng)選用臥式且為螺桿式的注射機進行成形加工。綜合考慮，初步確定為一模兩腔的結(jié)構(gòu)。此次設(shè)計的模具，其澆注系統(tǒng)為普通流道澆注系統(tǒng)?！?176。主流道進口端球面半徑R=R0+（1～2） （mm） 式中R0為噴嘴球面半徑，得R0=18mm，因此,R=18+2=20 (mm)。 圖5分流道是主流道與澆口之間的料流通道，是塑料熔體由主流道流入型腔的過渡段，負責(zé)將熔體的流向進行平穩(wěn)轉(zhuǎn)換，在多型腔模中起著將熔體向各個型腔分配的作用。澆口是分流道與型腔之間長度非常短，截面又很狹窄的一段料流通道。注射模閉合后，其內(nèi)部零部件將組合成一個能容納塑料的閉合空腔，即所說的型腔，它將接受由注射機注射出來的塑料熔體，并使它們在其內(nèi)部固化成形為塑料制品。參見《塑料成型工藝及模具簡明手冊》的規(guī)定，型腔的最小尺寸為基本尺寸，偏差為正值；型芯的最大尺寸為基本尺寸，偏差為負值。為實現(xiàn)分型時自動抽芯，把其設(shè)計成機動式的側(cè)向分型與抽芯機構(gòu)。其計算公式為 式中 p為塑料制品收縮對型芯單位面積的正壓力，一般取8～12MPa；A為塑料制品包緊型芯的側(cè)面積，單位為mm2。在抽芯距一定的情況下，角度越大，所需斜導(dǎo)柱就越短。斜導(dǎo)柱與定模板采用過度配合H7/m6，由于斜導(dǎo)柱在模具工作過程中主要用于驅(qū)動側(cè)向滑塊作往復(fù)運動，故側(cè)型芯的壓緊以及滑塊的導(dǎo)滑等問題均與斜導(dǎo)柱的安裝配合關(guān)系不大，所以斜導(dǎo)柱與滑塊斜孔之間可以采用過孔單邊間隙1mm。 （a） （b） （c） 圖12楔緊塊的楔角β必須大于斜導(dǎo)柱的傾角α，這樣才能保證模具合模時壓緊滑塊，開模時楔緊塊讓開，否側(cè)斜導(dǎo)柱將無法帶動滑塊完成抽芯動作。合模導(dǎo)向機構(gòu)在模具中，用來保證動模和定?；蚰?nèi)其它零部件之間準確對合，在模具中起定位、導(dǎo)向和承受一定側(cè)壓力的作用。因此，必須設(shè)有復(fù)位裝置或復(fù)位桿。其中包括模內(nèi)澆注系統(tǒng)和飛邊所用的的熔體量。模具的閉合高度應(yīng)在注射機最大與最小閉合高度之間，即模具的厚度應(yīng)在注射機允許的模具最大厚度和最小厚度之間。帶有側(cè)向抽芯機構(gòu)的模具，其開模行程的校核必須考慮側(cè)向抽芯距離。 hence, the solidifying casting is subjected to a higher rate of cooling, which in turn affects the microstructure and grain size within the casting.3. Composite molds, which are made of two or more different materials (such as sand, graphite, and metal) bining the advantages of each material. These molds have a permanent and an expendable portion and ate used in various casting processes to improve mold strength, control the cooling rates, and optimize the overall economics of the casting process.The general characteristics of sand casting and other casting processes are given in Table . Almost all mercially used metals can be cast. The surface finish obtained is largely a function of the mold material。 the majority is made with shell (see Section ), nobake, or coldbox processes. Cores are shaped in core boxes, which are used in much the same way that patterns are used to form sand molds. Sandmolding machines. The oldest known method of molding, which is still used for simple castings, is to pact the sand by hand hammering (tamping) or ramming it around the pattern. For most operations, however, the sand mixture is pacted around the pattern by molding machines. These machines eliminate arduous labor, offer highquality casting by improving the application and distribution of forces, manipulate the mold in a carefully controlled manner, and increase production rate.In vertical flaskless molding, the halves of the pattern form a vertical chamber wall against which sand is blown and pacted (). Then the mold halves are packed horizontally with the parting line oriented vertically and moved along a pouring conveyor. This operation is simple and eliminates the need to handle flasks, allowing for very highproduction rates, particularly when other aspects of the operation (such as coring and pouring) are automated.Sandslingers fill the flask uniformly with sand under a highpressure stream。 in the United States alone, about 15 million tons of metal are cast by this method each year. Typical applications of sand casting include machine bases, large turbine impellers, propellers, plumbing fixtures, and numerous ponents for agricultural and railroad equipment. The capabilities of sand casting are given in Table .Basically, sand casting consists of (a) placing a pattern (having the shape of the desired casting) in sand to make an imprint, (b) incorporating a gating system, (c) removing the pattern and filling the mold cavity with molten metal, (d) allowing the metal to cool until it solidifies, (e) breaking away the sand mold, and (f) removing the casting().Sands. Most sandcasting operations use silica sand (SiO2) as mold material. Sand is inexpensive and is suitable as mold material because of its hightemperature characteristics and high melting point. There are two general types of sand: naturally bonded (bank sand) and synthetic (lake sand). Because its position can be controlled more accurately, synthetic sand is preferred by most foundries. For proper functioning, mold sand must be clean and preferably new.Several factors are important in the