【正文】 y. too. are secured against rotating by fixing Bushings that ate wear parts are lilted into the stripper plate . To ensure the reliability of the stripping operation, the bushings and the fixed cores have conical seating surfaces. The temperature of the mold is controlled by five independent systems.System A+B: temperature control of the fixed cores in by means of bubblers.System C +D: temperature control of the splitcavity inserts takes place via several channels linked together into a largearea circuit.System temperature control of the mold plate is by means of two parallel channels connected to each other by a cross channel.The mold opens .it the parting line I—I the split cavity arrangement is pins There is releasing the external undercuts and lateral perforations A relative movement of the cavitymiserguiding stripper plate with respect to the core retainer plate is prevented In coupling the mold ejector bar ii I to the hydraulic ejector on the molding machine (not shown) Ejection takes place through the operation of the hydraulic ejector on the machine and the stripping action of the two stripper bushings the stripper plate. Discharge of the molded part is additionally ensured by an air blast the bubblers ha\e different diameters as a result of the different core diameters. The supply line for the temperature control fluid should be equal to or greater in crosssectional area than the remaining crosssectional area for the return flow. 1 his is function of the heat transmission coefficient a. which reaches its highest values at which flow ratesExamples 23Because of their geometrical shape, film spools require injection molds (Figs. 1 to 4) with slides (9, 10) which, in their closed state in the mold cavity form the inner surface of the spool on which the film will later ho wound. Suitable cores (2. 12) project inward into the doublewalled spool from both sides to form the spokes and drive rosettes the center holes in the spools are formed in the ejector side of the mold by movable cores that later function as sprue punches (16). A hotrunner system (15) with indirectly heated BeCu nozzle is used to feed melt to the sprues (13) with three pinpoint gates. Ejection of the spools takes place in such a way that first the sprues are separated from the nozzles (Fig. 5). Next the sprue is punched out of the hole in the hub (Fig. 6) before the spool itself is finally released (Fig. 7). This ensures that any further work on the spool is eliminated. Because of the need to punch out the sprues in the mold and thereby reduce finishing costs, it is only possible to use a hotrunner system with this twocavity mold. A conventional threeplate mold the multiple cavities and a normal runner system would increase costs to an unacceptable level. At the same time, the hotrunner system reduces the material losses arising from a normal runner system mold for Two Film Spools Made fromOn opening, the mold ponents and plates (4 to 8) that are bolted together and attached to the movable platen as well as plate (2), which is held by latch (23), move away from the mold half attached to the stationary platen of the molding machine. In this way, the sprues (13) are withdrawn from the sprue bushings. During this opening movement, the slides (9) and (10), which are guided on plate (5) by strips (3) and (4), are forced apart by the cam pins (II) so that each film spool is released around its circumference. At the same time, the hook at the end of latch (19) reaches the end of the groove cut in plate (1) and pulls the sprue punches (16) forward against the force of the springs (27) by means of punch plate (18). This pushes the sprues and runners out of the holes in the spool hubs until the hook at the end of latch (19) is lifted out of the groove by pin (20) moving onto the wedge (21). Further opening of the mold causes wedge (25) to engage pin (24), which then lifts latch (23), thus freeing plate (2 ), which has served to hold the molded parts. Stripper bolts (26) finally open the mold pletely by drawing plate away from the mold cavities. Lastly, actuation of the ejector (28) against the force of spring (2C)) pushes the film spools off the cores (12) through the action of ejector plate (30) and the attached ejector sleeves (32)Examples 58 For a bined dryer arel conveyor for thermoplastic tout. a sight glass was needed, lot which the mold show in figs i to5 was designed 1 lie sight glass was supposed to exhibit good transparency and withstand temperatures of up to 110 . and so polycarbonate was selected as the maternal A special feature of the sight glass is 。提前解決了許多實(shí)際生產(chǎn)的問題，提高了模具一次試模成功率。在計(jì)算型腔數(shù)后模具采用了一模二腔結(jié)構(gòu)，更有利于批量化和自動(dòng)化生產(chǎn)；在澆注系統(tǒng)的設(shè)計(jì)中選取流道截面的形狀，確定澆口尺寸；在設(shè)計(jì)調(diào)溫及冷卻系統(tǒng)中，確定冷卻時(shí)間，計(jì)算體積流量等；本此注塑模具設(shè)計(jì)采用的是推桿的脫模機(jī)構(gòu)，并進(jìn)行了設(shè)計(jì)校核；該模具屬于典型的簡單脫模機(jī)構(gòu)。結(jié) 論先說明了注塑成型模具的地位和當(dāng)今的現(xiàn)狀。如需返修，則應(yīng)提出相應(yīng)的返修意見，在記錄卡中應(yīng)摘錄成型工藝條件及操作注意點(diǎn)，著明產(chǎn)品的缺陷，最好能附上加工出來的制品，以供參考。 熔接痕：可能出現(xiàn)問題的原因(1)料溫太低，塑料的流動(dòng)性差；(2)注射壓力太小；(3)注射速度太慢；(4)模溫太低；(5)型腔排氣不良；(6)塑料受到污染。(16)檢查或更換止退環(huán)。(14)適當(dāng)升高模溫。(12)增料斗喉區(qū)的冷卻量，或降低射料缸后區(qū)溫度。(10)檢查所有的加熱器外層用安培表檢驗(yàn)?zāi)芰枯敵鍪欠裾_。(8)增加注塑速度。(6)增加熔膠溫度。(4)檢查止逆閥是否磨損或出現(xiàn)裂縫。(2)檢查料斗內(nèi)的塑料量。(14)止退環(huán)損壞，熔料有倒流現(xiàn)象。(12)模溫太低。(10)塑料貼在料斗喉壁上。(8)射嘴或射料缸外的加熱器不能運(yùn)作。(6)注塑壓力不足。(4)運(yùn)行時(shí)間變化。(2)塑料短缺。 塑件充填不滿：注塑件缺陷的特征： 注塑過程不完全，因?yàn)槟Ｇ粵]有填滿塑料或注塑過程缺少某些細(xì)節(jié)。(7)適當(dāng)增加冷卻時(shí)間或改善冷卻條件，盡可能保證動(dòng)、定 模的模溫一致。(5)增加塑料溫度。從模具內(nèi)（尤其是 較厚的注塑件）頂出后立即浸入溫水中（38oC）使注塑 件慢慢冷卻。(2)減少螺桿向前時(shí)間。(7)注塑件結(jié)構(gòu)不合理（如加強(qiáng)筋集中在一面，但相距較遠(yuǎn)）。(5)注塑件在頂出時(shí)太熱。(3)模腔內(nèi)塑料不足?？赡艹霈F(xiàn)問題的原因：(1)彎曲是因?yàn)樽⑺芗?nèi)有過多內(nèi)部應(yīng)力。(7)適當(dāng)擴(kuò)大流道的拔出斜度。 (5)增加冷卻時(shí)間，但更好的辦法是使用有較小注口的注口 套代替原本的注口套。(3)減少螺桿向前時(shí)間。 補(bǔ)救方法：(1)重新將射嘴和注口套對準(zhǔn)。(5)注口套的圓弧面與射嘴的圓弧面配合不當(dāng)，出現(xiàn)裝似 “冬菇”的流道。(3)射嘴溫度太低?？赡艹霈F(xiàn)問題的原因：(1)注口套與射嘴沒有對準(zhǔn)。 制品表面有波紋或銀絲：可能出現(xiàn)問題的原因：(1)塑料含有水分和揮發(fā)物；(2)料溫太高或太低；(3)注射壓力太?。?4)流道和澆口的尺寸太大；(5)嵌件預(yù)熱回溫度太低； (6)制品內(nèi)應(yīng)力太大。(12)選擇適合模具的塑料品種（主要從縮率及機(jī)械強(qiáng)度慮）。(11)檢查液壓系統(tǒng)運(yùn)作是否正常，油溫是否過高或過低（25—6039。(9)檢查運(yùn)作時(shí)間的不一致性。(7)檢查是否錯(cuò)誤的進(jìn)料設(shè)定。(5)檢查是否每次運(yùn)作都有穩(wěn)定的熔融熱料。(3)檢查與溫度控制器一起使用的熱電偶是否屬于正確類型。 補(bǔ)救方法：(1)檢查有無充足的冷卻水流經(jīng)料斗喉以保持正確的溫度。(8)使用了不適合模具的塑料品種。(6)運(yùn)作時(shí)間的變化、溶液黏度不一致。(4)注塑壓力不穩(wěn)定。(2)射料缸溫度或波動(dòng)的范圍太大。制品成型尺寸精度低注塑件缺陷的特征：注塑過程中重量尺寸的變化超過了模具、注塑機(jī)、塑料組合的生產(chǎn)