【正文】 shrinkage. Polystyrene is easy to burn, lit the fire source will continue to burn out, acpanied by smoke. Need to be considered in the design of the mold products, some characteristics of the material. The dimensions and size of the internal structure of the products are mostly of the standard series, in the mold design, it is better to make use of standard parts as many as possible. By analyzing the physical characteristics and material properties of the products, we can select the appropriate subsurface. By calculating I choice the XSZY125 as the injection machine model. From the main channel gating system, shunt, gate and cold material points posed of four parts. The conical shape of the main channel is good for the flow of melt and pouring mold material when the main channel smooth pull up. Main channel directly affects the size of the melt flow rate and filling time. In addition, because of its hightemperature melt and plastic injection molding machine nozzle repeatedly lifted, so the design midfield designed to replace the removable gate sets. . This requirement does not allow plastic deformation defects and cracks, the surface quality requirements. I choose fourcavity mold injection, to facilitate adjustment of the shear rate and die at closing time, I choose side gate. The crosssectional shape is simple, easy processing, easy to fix after the tryout, and the opening in the subtype surface, the feed from the edge of the cavity. After the injection molding of plastic parts, plastic parts in the mold cooling, due to volume contraction, tight package of core power generation, when it was introduced from the mold, it must overe the bag tight friction force generated. On the bottom of the barrel, nonporous, shell type plastic parts, mold release when they overe the atmospheric pressure. Core of the molding ends, generally to design stripping slope, the other, the beginning plastic parts ejection, the ejection force required for the largest, followed by the introduction of the role of force is introduced to overe the machine only for the organization moving of friction. The plastic parts are putting Stripping. 首先，模具型腔的形狀、尺寸、表面光潔度、分型面、進(jìn)澆口和排氣槽位置以及脫模方式等對(duì)制件的尺寸精度和形狀精度以及制件的物理性能、機(jī)械性能、電性能、內(nèi)應(yīng)力大小、各向同性性、外觀質(zhì)量、表面光潔度、氣泡、凹痕、燒焦、銀紋等都有十分重要的影響。因此促進(jìn)模具的不斷向前發(fā)展 模具的發(fā)展趨勢(shì)目前，我國(guó)模具生產(chǎn)廠點(diǎn)約有3萬(wàn)多家，從業(yè)人數(shù)80多萬(wàn)人。在CAD/CAM技術(shù)得到普及的同時(shí)，CAE技術(shù)應(yīng)用越來(lái)越廣，以CAD/CAM/CAE一體化得到發(fā)展，模具新結(jié)構(gòu)、新品種、新工藝、新材料的創(chuàng)新成果不斷涌現(xiàn)，特別是汽車、家電等工業(yè)快速發(fā)展，使得注塑模的發(fā)展迅猛[4]。目前雖然已有重量為萬(wàn)分之一克的注射制品成型加工技術(shù)裝備，也已有直徑為1mm的塑料管生產(chǎn)設(shè)備和3ml的中空吹塑機(jī)等，但是日本已提出開(kāi)發(fā)重量為十萬(wàn)分之一克的注射成型加工裝備；，已為一些國(guó)家在研發(fā)中[7]。與其它革新技術(shù)一樣，這一新機(jī)型成本高昂，業(yè)界對(duì)其持懷疑態(tài)度，因此，初其并未獲得大幅度推廣，致使業(yè)界難于認(rèn)識(shí)其優(yōu)勢(shì)。由于產(chǎn)品應(yīng)用的擴(kuò)大，于是出現(xiàn)了各種大型、精密和高壽命的成型模具，為了滿足這些要求，研制了各種高強(qiáng)度、高硬度、高耐磨性能且易加工、熱處理變形小、導(dǎo)熱性優(yōu)異的制模材料。要求模具公司盡快交貨，這已成為一種趨勢(shì)。中國(guó)模具行業(yè)目前已有10多個(gè)國(guó)家級(jí)高新技術(shù)企業(yè)，約200個(gè)省市級(jí)高新技術(shù)企業(yè)。現(xiàn)在，能把握機(jī)遇、開(kāi)拓市場(chǎng)，不斷發(fā)現(xiàn)新的增長(zhǎng)點(diǎn)的模具企業(yè)和能生產(chǎn)高技術(shù)含量模具企業(yè)的業(yè)務(wù)很是紅火，利潤(rùn)水平和職工收入都很好。（2）工藝裝備落后，組織協(xié)調(diào)能力差。同時(shí)，工業(yè)發(fā)達(dá)國(guó)家的模具正在加速向中國(guó)轉(zhuǎn)移，國(guó)際采購(gòu)越來(lái)越多，國(guó)際市場(chǎng)前景看好。為了滿足市場(chǎng)需要，未來(lái)的塑料模具無(wú)論是品種、結(jié)構(gòu)、性能還是加工都必將有較快發(fā)展，而且這種發(fā)展必須跟上時(shí)代步伐。 2 塑件分析及分型面設(shè)計(jì) PS的性能PS的結(jié)構(gòu)聚苯乙烯的分子鏈上交替連接著側(cè)苯基。～，尺寸穩(wěn)定性好，收縮率低。聚苯乙烯的線膨脹系數(shù)較大，為（6～8)X105K1，與金屬相差懸殊甚大，故制品不易帶有金屬嵌件。(6)加工性聚苯乙烯是一種無(wú)定形的聚合物，沒(méi)有明顯的熔點(diǎn)，從開(kāi)始熔融流動(dòng)到分解的溫度范圍很寬，約在120～180℃之間，且熱穩(wěn)定性較好，因此，成型加工可在很寬的范圍內(nèi)進(jìn)行。擠出成型可采用普通的擠出機(jī)。另預(yù)置澆道凝料為2cm3因此估算蜜餞盒盒蓋體積為：；蜜餞盒盒體體積為： 注射機(jī)型號(hào)的確定（1）注射量的計(jì)算通過(guò)三維軟件設(shè)計(jì)分析計(jì)算得蜜餞盒盒蓋體積為：；蜜餞盒盒體體積為：； 蜜餞盒盒蓋質(zhì)量為：；蜜餞盒盒體質(zhì)量為：； （2）澆注系統(tǒng)凝料體積的初步估算澆注系統(tǒng)的凝料在設(shè)計(jì)之前是不能確定準(zhǔn)確的數(shù)值。對(duì)于粘度較大的精度較高的塑料制品應(yīng)該取較大值。2） 主流道小端直徑：=注塑機(jī)噴嘴尺寸+（~1）mm=(4+)mm=3） 主流道大端直徑：=+，式中。單邊分流道長(zhǎng)度L分取35mm。2）計(jì)算分流道體積流量：q分=（V分+V塑）/t=(+)/=3）計(jì)算得到剪切速率為γ=103/()3=103s1該分流道的剪切速率處于澆口主流道和分流道的最佳剪切速率5102~5103之間，所以分流道內(nèi)的熔體的剪切速率合格。根據(jù)手冊(cè)，可得側(cè)澆口的深度h計(jì)算公式為h=nt=2mm=1mm式中，t是塑件壁厚，這里t=；n是塑料成型系數(shù)。（1）計(jì)算主流道的體積流量Q=(V主+V分+nV塑)/t=（++1）/=（2）計(jì)算主流道的剪切速率計(jì)算主流道的剪切速率得到其值處于澆口與分流道的最佳剪切速率之間，所以主流道的剪切速率校核合格。（2）凸模的結(jié)構(gòu)設(shè)計(jì)凸模是成型塑件內(nèi)表面的成型零件，通?？梢苑譃檎w式和組合式兩種類型。（2）凹模深度尺寸的計(jì)算根據(jù)塑性成型零件可知：H1=60mm，H2=12mm，相應(yīng)的制造公差為Δ=。（2）凹模深度尺寸的計(jì)算根據(jù)塑性成型零件可知：H1=20mm，H2=10mm，相應(yīng)的制造公差為Δ=。因此，應(yīng)通過(guò)強(qiáng)度和剛度計(jì)算來(lái)確定型腔壁厚。由于型腔采用直線、對(duì)稱結(jié)構(gòu)布置，故型腔之間壁厚滿足結(jié)構(gòu)的設(shè)計(jì)要求了。甚至因氣體受而產(chǎn)生高溫，使塑件焦化。對(duì)底部無(wú)孔的筒、殼類塑件，脫模推出時(shí)還要克服大氣壓力。脫模時(shí)間為t=8s，則注射時(shí)間周期為20s，則每小時(shí)注射次數(shù)為180次。而進(jìn)一步的模具裝配及分解視圖更是極為具體的展現(xiàn)了合模與脫模過(guò)程，使得我對(duì)模具的理解更深一層。 revised 7 August 2007