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1、注射模具設(shè)計和 新型注射成型技術(shù) 塑料注射模具是現(xiàn)在所有塑料模具中使用最廣的模具，能夠成型復雜的高精度的塑料制品。 下面 只是粗略介紹一下。 設(shè)計塑料注射模具首先要對塑料有一定的了解，塑料的主要成分是聚合物。如我們常說的 ABS 塑料便是丙烯腈、丁二烯、苯乙烯三種單體采用乳液、本體或懸浮聚合法生產(chǎn)，使其具有三種單體的優(yōu)越性能和可模塑性，在一定的溫度和壓力下注射到模具型腔，產(chǎn)生流動變形，獲得型腔形狀，保壓冷卻后頂出成塑料產(chǎn)品。聚合物的分子一般呈鏈狀結(jié)構(gòu)，線型分子鏈和支鏈型分子認為是熱塑性塑料，可反復加熱冷 卻加工，而經(jīng)過加熱多個分子發(fā)生交聯(lián)反應，連結(jié)成網(wǎng)狀的體型分子結(jié)構(gòu)的塑料通常是一此次性的，不
2、能重復注射加工，也就是所說的熱固性塑料。 既然是鏈狀結(jié)構(gòu)，那塑料的在加工時收縮的方向也是跟聚合物的分子鏈在應力作用下取向性及冷卻收縮有關(guān)，在流動方向上的收縮要比其垂直方向上的收縮多。產(chǎn)品收縮也同制品的形狀、澆口、熱脹冷縮、溫度、保壓時間及內(nèi)應力等因素有關(guān)。通常書上提供的收縮率范圍較廣，在實際應用中所考慮的是產(chǎn)品的壁厚、結(jié)構(gòu)及確定注塑時溫度壓力的大小和取向性。 一般產(chǎn)品如果沒有芯子支撐，收縮相應要大些。 塑料注塑 模具基本分為靜模和動模。 注射模：注射模主要是用來生產(chǎn)熱塑性的零件，盡管有些工藝已經(jīng)發(fā)展為可以用注射模來生產(chǎn)熱固性材料的零件。在從一個熔化的熔料箱中把熔料注入型腔中，是相當難解決在這種
3、情況下熱固性塑料在幾分鐘內(nèi)凝固的問題。注射模的工作原理跟鍛造模十分相似。當柱塞向后拉時，塑料粉末被載入加料斗，還有一定數(shù)量的塑料進入了加熱腔。塑料粉末在加熱腔中受到熱力和壓力的作用下熔化。加熱的溫度范圍在 265 500 華氏度之間。壓力在 12000 30000PMa 之間作用下，柱塞向前移動，把熔化的塑料注入模具的型腔中。由于模具 被流通的冷水冷卻，塑料凝固成型，當柱塞向后拉出和開模，塑件脫模。注射機可以設(shè)計為人工、斗自動、全自動操作。以每分鐘注射四次的速率，典型注射機生產(chǎn)的塑件可重達22 盎司，某些注射機可達到每分鐘注射六次。除了表面電鍍外， 這類模具的用途與鑄造模相似。注射模的優(yōu)點是：
4、 1、 高速注射模適用于大批量生產(chǎn)是可能的 ； 2、 熱塑性材料的廣泛選擇產(chǎn)生了各種有用的特性。 3、 螺紋模具，飛邊，側(cè)孔大的薄壁結(jié)構(gòu)的應用成為可能。 成型理論 :板料沖壓成形成功機率著沖壓件形狀的復雜程度減少而增加 ,沖壓成形的目的是生產(chǎn)具有一定尺寸 ,形狀并 有穩(wěn)定一致應力狀態(tài) ,甚至無起皺無裂紋的沖壓件 . 沖壓有一種至多種成形方式用來成型所需形狀 ,它們是彎曲 ,局部成形 ,拉深 ,局部成形用來成形 ,凹陷形狀或凸包 ,拉深用來成形 ,啤酒罐之類的沖壓件 ,隨著沖壓件的形狀越來越復雜 ,多種成形方法將會被用到同一零件的成型中 ,事實上 ,有很多沖壓件上同時有彎曲 ,局部成型 ,拉深模
5、具成型的特征 ,通常有三種形式的模具 ,它們是自由成型 ,局部成形以及拉深形式 . 自由成形 自由成形是用的最基本的一種成形材料的成形模具 ,這類模具只是簡單地通過一個沖頭在壓力機下行過程中把材料“撞擊”進入凹模中成形 材料。得到的是由無控制材料流動導致的應罰狀態(tài)的沖壓件，由無約束材料流動產(chǎn)生的“松弛金屬區(qū)”的出現(xiàn)，沖壓件尺寸和形狀上趨于不穩(wěn)定。 局部成形 成形工序中用一壓邊圈來控制材料流動壓邊圈是置于模具上的一個多壓裝置，由帶壓邊圈模具成形的沖壓件可分為三部分，它們分別是產(chǎn)品表面，壓邊圈以及連接這兩部分的壁，在凸模一端壁與壁之間的角稱作凸模過渡區(qū)。 凸模模穴理論上是在壁與壓邊圈面的交叉處，凸
6、模被置于凸模穴之中，而壓邊圈被放在凸模穴外凸模的周圍，這種模具還有上面的裝置將壓邊圈與凸模聯(lián)接起來，片料或工序件放到指定位置后壓力機 下行，上模開始接觸片料，壓邊圈在凸模周圍的材料上壓出一些鎖緊臺階或筋，從防止成形過程中材料從壓邊圈流向凸模部分隨壓邊圈不再發(fā)生作用，材料不斷地變形直到成形為凸模下部成形部分形狀，在壓力機回程時，模具做與下行時相反的動作，最后已經(jīng)成形的沖壓件被從模具上移走，就完成了一沖局部成形。 拉深 拉深的得名并不是因為材料在成形中變形情況得來，而是因為在拉深過程中材料進入拉離壓邊圈表面，直入凸模下面盡管拉深變形產(chǎn)生在拉深模中，但很多局部成形，彎曲模在工作過程中也對板料進行不同
7、程度的拉深變形。 拉深模的工作機制，與局部成形 模具非常類似，不同的是，在拉深模中，壓邊圈部分有特定的地方必須更加嚴格地控制材料流入凹模量，以防止起皺，拉深模中，控制材料流入是通過成形半月型的拉深筋來代替局部成形中的鎖緊臺階，一般在直邊部分設(shè)一至三條，以控制這部分的材料流入而在復雜邊部分少設(shè)或不設(shè)拉深筋，當板料工序件放到模具相應位置后，拉深的第一個階段是模具是板料以及壓邊圈的接觸 . 毛坯上為考慮到拉深過程中毛坯圓周沿走私方向減少留有的法蘭邊 ,是所有材料中流動最儔的地方 ,隨著壓力機滑塊繼續(xù)下行 ,材料變形流過凹模圓角半徑 .板料開始形成與凸模一致的形狀，在拉深 的工序中，這部分很少發(fā)生變形
8、。被除數(shù)壓在凹模腔中的空氣由于凸模以及制件的下降而從氣孔中排出。 凸模、凹模的圓角半徑應為 4-6 倍料厚以防止裂紋及起皺 隨著模具繼續(xù)閉合，校形開始發(fā)生，彎過凹模圓角材料，變形成鈑金件的直壁部分，壓邊圈下邊 的材料被拉入凹模并彎過凹模圓部分，考慮到防止材料被拉裂，凹模圓角半徑應為 4-10 個料厚。毛坯變形情況為周向壓縮么向拉伸，這樣被拉入凹模圓腔中的工序稱為拉深，拉深過程有：摩擦壓縮、拉伸。因此，拉深過程中，壓力機必須提供足夠大的壓力，以克服拉深過程中的各種抗變形力，如：壓邊圈與毛坯 間的靜摩擦力，額外的力也是必須的，用來克服拉深過程中滑支摩擦力?？朔蓧哼吶澾^凹模圓角在后面行程中校直成
9、直壁材料的變形力。在毛坯被拉入凹模沉著凹模半徑變彎，在接下來變形中校直的同時，壓邊圈部分毛坯被沿周向壓縮。而且沿著圓周半徑方向上壓縮量隨著半徑增大而增大 半徑越大的地方，需壓縮的面積也大，這樣的結(jié)果是壓邊圈部分的材料變厚，而凸模部分的材料因為被拉深變薄。在有些拉深中，拉深變形使拉深壁變形成卷曲形或弓形。最薄的區(qū)域是沖壓件直壁與圓角過渡部分，因為這部分在拉深過程中拉伸變形最久，受力最大，這里往往也是最容 易拉裂的地方，因為這部分的加工硬化少于其它地方。 拉深工序到壓力機行程下死點結(jié)束，拉深工序結(jié)束后，壓力機滑塊上行，模具打開，奢力圈在彈性元件作用下，從凸模上卸下包附在凸模上的沖壓件，沖頭下面 沒
10、有通氣孔，當沖壓件被壓邊圈推起時，空氣可進入。沖壓件離開凸模產(chǎn)生的真空部分如果不設(shè)通氣孔，沖壓件將很難脫出。 計算機輔助成型 采用計算機輔助工程（ CAE）對加工設(shè)計及分析有助于縮短設(shè)計周期并可避免代價昂貴的機械失誤。商業(yè)性仿真代碼常用于流道上標明尺寸，以平衡熔料在流道系統(tǒng)及型腔內(nèi)的流動，同時確定澆口的最佳開設(shè)置 和澆口的數(shù)目。計算注射壓力和合模噸位要根據(jù)不同的加工條件和材料而定。收縮率及翹曲率結(jié)合初始流向也可準確估算出來。重要的是要使得這種設(shè)計工具幫助熟練分析人員在某個設(shè)計方案或加工研究時進行判斷的操作。結(jié)果必須理解為以研究對象和加工 /材料為前提。當考慮采用這種方法準確輸入數(shù)據(jù)后，可取得巨
11、大的效益。另外，這種分析經(jīng)濟性可使設(shè)計周期更短和所需的生產(chǎn)時間更短。 應該提醒注意的是，商業(yè)性的 CAE 程序通常是不可直接使用的。充模仿真可產(chǎn)生有價值的見識，但結(jié)果必須重新對其局限性進行重新考慮估計。應用現(xiàn)代計算機進行注射成 型模擬試驗，僅限于純粘性流體（不包括粘彈性的熔融塑料）。可預測熔體流入型腔的實際流動速率組成結(jié)構(gòu)和性能公布等，如可進行高精度的粘彈性分析。目前所采用的任何其它加工方式都不可能達到這種先進水平，并且最近幾年來，由仿真設(shè)備的工業(yè)界帶頭者和大學里的研究小組已取得了良好的進展。有幾家公司正在努力探索仿真技術(shù)，以求能正確地解釋更多現(xiàn)實的塑性行為和加工現(xiàn)象。例如，聚合物主鏈的取向?qū)?/p>
12、局部的物理性能和性能分布的影響。加工物理學是非常復雜的，而某些粘彈性體現(xiàn)象仍然沒有完全弄清楚，更完善合理的加工方式目前正緩慢形成。這些更強的 有力的方式將獲得大大超過目前所設(shè)計的生產(chǎn)能力。 共注射成型（芯層注射成型） 采用共注射成型有助于觀察到制件中獨特的結(jié)構(gòu)。塑料“甲”先注射充入部分型腔，然后塑料：“乙”緊跟著“甲”注射進入型腔并保持初始推動流動壓力場。根據(jù)表皮區(qū)和芯層的尺寸大小，按正確的比例關(guān)系計量出“甲”和“乙”的用料量，可制得 1 個內(nèi)芯層為“甲”外表完全由“乙”包裹的制件。 另外，在化妝品應用方面，有小部分的表皮“甲”料放在“乙”料之后注射，以使?jié)部诓糠值谋砥つ芡耆]合。用 2 種不
13、同顏色的樹脂進行共注射成型的制件，形成一個容易 區(qū)分的表皮和芯層區(qū)間（認識到所有的注射成型件中存在有類似的表皮和芯層這一點非常重要。）如果沒有先進的檢測技術(shù)，通常難以區(qū)分表皮 芯層的區(qū)域及其分界面。 共注射成型并非一門新的工藝技術(shù)。英國 ici 公司早在 70 年代就開始應用這一技術(shù)，并取得了包括基礎(chǔ)理論，生產(chǎn)產(chǎn)品及機器設(shè)備等幾項專利?，F(xiàn)普遍采用的 ici 生產(chǎn)工藝類似“三明治模塑”，由于模塑外層表皮的材料與中間或芯層的材料不同，因此兩種材料必須有一定的相容性，并且芯層材料要求具有可高度輻射、發(fā)泡成型和 100%回收利用等性能。選用材料應經(jīng)多種選擇比較而定。 共注射成型工藝問世 15 年后，才
14、真正得以普及推廣。一種采用共注射成型的厚齒輸制作橫截面。 表皮材料是非填充尼龍，而芯層材料是玻璃 -珠料 -填充尼龍。芯層中玻璃珠粒料收縮率極低，具有良好的尺寸穩(wěn)定性。尼龍表皮賦予齒輪齒牙良好的潤滑性并避免了珠粒料容易產(chǎn)生的磨蝕問題。 基于共注射成型的基礎(chǔ)理論目前已開發(fā)出幾種新型加工改進方法。例如，模內(nèi)“上漆”和氣體輔助模塑成型擴大了采用這種工藝的范圍。模內(nèi)上漆加工方法是采用低分子量聚合物作為外層材料，而氣體輔助模塑成型是采用氮氣或另一種氣體作為芯層（或部分芯層）材料。隨著 產(chǎn)品設(shè)計與生產(chǎn)加工設(shè)備的不斷完善改進，將滿足各種新應用和新技術(shù)的需求，共注射技術(shù)必將成為富有潛力的工業(yè)化大規(guī)模生產(chǎn)工藝方
15、法。 交變注射成型 相比較而言，交變注射是一個比較新的注射成型選擇參數(shù)。這項技術(shù)的最大難點在于當加工條件突然改變時，對塑料熔體將呈現(xiàn)出怎樣的變化行為知之甚少。有關(guān)熔體流變學的基礎(chǔ)知識，不僅僅是固定的剪切粘度。確切地說，熔體響應（粘性和彈性行為）需要表達的特性，不僅是通常的穩(wěn)態(tài)流動速率或剪切速率及溫度，也包括壓力及瞬間流動速率。這些特性包括很多內(nèi)容而且十分難于弄清楚。然而，如果在異型 材注射方面取得實質(zhì)性進展，將需制訂出多種不同塑料的具體操作規(guī)程。另還需增加通用的累試法，以求得到成熟和精確的控制方法。 在常規(guī)的注射成型中，型腔壁固定不變，某些情況下，還有利用在充模和保壓陷段移動模壁?？刹捎?2
16、種不同的方法：移動型腔壁方向垂直于分模線；旋轉(zhuǎn)或滑動型腔壁。在充模階段旋轉(zhuǎn)型芯以增加對制件尤其是表皮部分分子的變軸取向。通過這種加工工藝，制件的彎曲性能與其它機械性能得到了極大的提高。聚苯乙飲水杯和聚丙烯注射器就是采用這種加工方法獲得重大改變突破地 2 個產(chǎn)品。 Injection mold design and the new-type injekt by shaping technologe The plastic injection mold is in the present all plastics mold，uses the broadest mold, can take shap
17、e the complex high accuracy， plastic product. Under only is sketchily introduces. The design plastic injection mold first must have the certain，understanding to the plastic, the plastic principal constituent is a polymer. Like we often said the ABS plastic then is the propylene nitrile, the pyprolyl
18、ene, the styrene three kind of monomers uses the emulsion, the main body or aerosol gathers the legitimate production,enable it to have three kind of monomers the high performance and may the compression molding, injects under the certain temperature and the pressure to the mold cavity, has the flow
19、 distortion, the obtaining cavity shape, after guarantees presses cooling to go against becomes the plastic product. The polymer member assumes the chain shape structure generally, the linear molecule chain and a chain molecule thought is the thermoplastic, may heat up the cooling processing repeate
20、dly, but passes through heats up many members to occur hands over the association response, including forms netted the build molecular structure plastic usually is this, cannot duplicate injects the processing, also is the thermosetting plastics which said. Since is the chain shape structure, that p
21、lastic when processing contracts the direction also is with the polymer molecular chain under the stress function the orientation and the cooling contraction related, must be more than in the flow direction contraction its vertical direction in contraction. The product contraction also with the prod
22、uct shape, the runner, the temperature,guarantees presses factor and so on time and internal stress concerns.In the usual book provides the shrinkage scope is broad, considers is product wall thickness, the structure and the determination casts the temperature pressure size when the practical applic
23、ation and the orientation. The common product if does not have the core strut, the contraction correspondingly wants big. The plastic casts the mold basically to divide into the static mold and to move the mold. Injection Molding . Injection molding is principally used for the production of thermolp
24、lastic part ,although some progress has been made in developing a method for injection molding some thermosetting materials .The problem of injecting a melted plastic into a mold cavity from a reservoir of melted material has been extremely difficult to solve for thermosetting plastics which cure an
25、d harden under such conditions within a few minutes 。 The principle of injection molding is quite similar to that of die-casting . Plastic powder is loaded into the feed hopper and a certain amount feeds into the heating chamber when the plunger draws back . This plastic powder under heat and pressu
26、re in the heating chamber becomes a fluid. Heating temperatures range from 265 to 500F . After the mold is closed , the plunger moves forward some of the fluid plastic into the mold cavity under pressures ranging from 12000 to 30000 psi . Since the mold is cooled by circulating cold water , the plas
27、tic hardens and the part may be ejected when the plunger draws back and the mold opens .Injection-molding machines can be arranged for manual operation, automatic single-cycle operation , and full automatic operation . Typical machines produce molded parts weighing up to 22 ounces at the rate of fou
28、r shots per minute , and it is possible on some machines to obtain a rate of six shots per minute . The molds used are similar to the dies of a die-casting machine with the exception that the surfaces are chromium-plated . The advantages of injection molding are : 1. A high molding speed adapted for
29、 mass production is possible. 2. There is a wide choice of thermoplastic materials providing a variety of useful properties. 3. It is possible to mold threads , undercuts , side holes ,and large thin sections. Forming Theory:The confidence level in successfully forming a sheetmetal stamping increase
30、s as the simplicity of the parts topography increases. The goal of forming with stamping technologies is to produce stampings with complex geometric surfaces that are dimensionally accurate and repeatable with a certain strain distribution, yet free from wrinkles and splits. Stampings have one or mo
31、re forming modes that create the desired geometries. These modes are bending, stretch forming and drawing. Stretching the sheetmetal forms depressions or embossments. Drawing compresses material circumferentially to create stampings such as beer cans.As the surfaces of the stamping become more compl
32、ex, more than one mode of forming will be required. In fact, many stampings have bend, stretch and draw features produced in the form die. The common types of dies that shape material are solid form, stretch form and draw. Solid Form The most basic type of die used to shape material is the solid for
33、m die. This tool simply displaces material via a solid punch “crashing” the material into a solid die steel on the press downstroke. The result is a stamping with uncontrolled material flow in terms of strain distribution. Since “l(fā)oose metal” is present on the stamping, caused by uncontrolled materi
34、al flow, the part tends to be dimensionally and structurally unstable. Stretch Form Forming operations that provide for material flow control do so with a blankholder. The blankholder is a pressurized device that is guided and retained within the die set. Stampings formed with a blankholder may be d
35、escribed as having three parts, They are the product surface, blankholder surface and a wall that bridges the two together. The theoretical corner on the wall at the punch is called the punch break. The punch opening is the theoretical intersection at the bottom of the draw wall with the blankholder
36、. The male punch is housed inside the punch opening, whereas the blankholder is located around the punch outside the punch opening. These tools have a one-piece upper member that contacts both the blankholder and punch surfaces. A blank or strip of material is fed onto the blankholder and into locat
37、ion gauges. On the press downstroke, the upper die member contacts the sheet and forms a lock step or bead around the outside perimeter of the punch opening on the blankholder surface to prevent material flow off the blankholder into the punch. The blankholder then begins to collapse and material st
38、retches and compresses until it takes the shape of the lower punch. The die actions reverse on the press upstroke, and the formed stamping is removed from the die. Draw The draw die has earned its name not from the mode of deformation, but from the fact that the material runs in or draws off the bla
39、nkholder surface and into the punch. Although the draw mode of deformation is present in draw dies, some degree of the stretch forming and bending modes generally also are present. The architecture and operational sequence for draw dies is the same as stretch-form dies with one exception. Material f
40、low off the blankholder in draw dies needs to be restrained more in some areas than others to prevent wrinkling. This is achieved by forming halfmoon-shaped beads instead of lock steps or beads found in stretch-form dies. The first stage of drawing sheetmetal, after the blank or strip stock has been
41、 loaded into the die, is initial contact of the die steel with the blank and blankholder. The blank, round for cylindrical shells to allow for a circumferential reduction in diameter, is firmly gripped all around its perimeter prior to any material flow. As the press ram continues downward, the shee
42、tmetal bends over the die radius and around the punch radius. The sheetmetal begins to conform to the geometry of the punch.Very little movement or compression at the blank edge has occurred to this point in the drawing operation. Air trapped in the pockets on the die steel is released on the press
43、downstroke through air vents. The die radius should be between four and 10 times sheet thickness to prevent wrinkles and splits. Straightening of sheetmetal occurs next as the die continues to close. Material that was bent over the die radius is straightened to form the draw wall. Material on the bl
44、ankholder now is fed into the cavity and bent over the die radius to allow for straightening without fracture. The die radius should be between four and 10 times sheet thickness to prevent wrinkles and splits. The compressive feeding or pulling of the blank circumferentially toward the punch and die
45、 cavity is called drawing. The draw action involves friction, compression and tension. Enough force must be present in drawing to overcome the static friction between the blank and blankholder surfaces. Additional force is necessary during the drawing stage to overcome sliding or dynamic friction an
46、d to bend and unbend the sheet from the blankholder surface to the draw wall. As the blank is drawn into the punch, the sheetmetal bends around the die radius and straightens at the draw wall. To allow for the flow of material, the blank is compressed. Compression increases away from the die radius
47、in the direction of material flow because there is more surface area of sheetmetal to be squeezed. Consequently, the material on the blankholder surface becomes thicker.The tension causes the draw wall to become thinner. In some cases, the tension causes the draw wall to curl or bow outward. The thi
48、nnest area of the sheet is at the punch radius, and gradually tapers thicker from the shock line to the die radius. This is a probable failure site because the material on the punch has been work-hardened the least, making it weaker than the strain hardened material. The drawing stage continues unti
49、l the press is at bottom dead center. With the operation now complete, the die opens and the blankholder travels upward to strip the drawn stamping off of the punch. Air vents provided in flat or female cavities of the punch allow air to travel under the material as it is lifted by the blankholder.
50、The stamping will have a tendency to turn inside out due to vacuum in the absenceof air vents. Computers Supplementary Shaping Adopt computer assist project( CAE) design and analyse and help and shorten design cycle and prevent cost from expensive mechanical fault processing. Commercial emulations d
51、aily to indicate size on flowing one code, melt material flows in flowing dishes of system and type with balance, The figure of offeredding and put bestly and runner defining runner at the same time . Calculate pressure of injecting and shut mould want at different processing terms and material fix
52、by tonnage. And warping rate combine initial to flow into too very accurate to estimate out person who shrink. What is important is and want and make the design tool help and analyse personnel process and go on the operation judged while studying or in a certain plan of design skillfully. Understand
53、 at results and cant process in order that it is by research object /materials from prerequisite. After consider adopting this kind of method accurate data-in , can make enormous benefit . In addition, economic make design cycle not to be short and needs produce shorter time the analysis. The one th
54、at should point out is, commercial cae procedures usually cant be used directly. It fills and imitate and produce valuable experience but the result must rethink its limitation to estimate again . Use modern computers go on and inject shaping simulated test and limited to pure viscidity fluids only(
55、 include the melting plastic of viscoplasticity ). One actual flow form measurable melting body person who flow intoes and performance announce etc. structure by speed, If can carry on the viscoplasticity analysis of high accuracy . At present adopt any other to process way reach this advanced compe
56、tences, And recent years, at emulation the industrial circle person who take the leads of equipment and the research groups of university already made good progress. Have several a of companies make great efforts and probe emulation technology, in order to be be able to be being explained moulding t
57、he sex instinct act and process the phenomenon of more reality correctly. For example, get together on the influence that the orientation of the possessive chain is distributed to some physics performance and performance . Processing physics is very complicated, but some viscoplasticity is embodied
58、too alike to still totally understood , Perfect the rational processing way and taking shape slow at present even more. These stronger strong ways will be exceeded the production capacity that will be designed at present greatly . Inject By Shaping Altogether( inject shaping of at core layers) Adopt
59、 and inject shaping help and observe and make one unique structure altogether. first of plastic is injected and fill and enter some types first, then the plastic: second follow first inject person who enter one and keep initial to drive pressure field of flowing closely. At epidermis district and co
60、re the sizes of one, measure and publish first and the materials quantities of second according to correct proportionate relationship, Make one at first complete at second to make one parcel appearance core each. In addition, in cosmetics application, the material is put after second material inject
61、ing to have first of epidermis of the small part, So that the epidermis of the part of the runner can be totally closed. Inject making one of shaping altogether with the resin of 2 kinds of different colors, form a piece of a layer of blocks of epidermis and core apt to distinguish (Realize inject s
62、haping one as much as all have and have and one very much important this core similar epidermis. )If there is not advanced detection technique, usually difficult to distinguish the epidermis - core area and boundary of layer. Inject shaping a new technology altogether. British ici company began to u
63、se this technology in the 1970s early, and had made the basic theory of including, Produce several patents, such as the products and machinery equipment,etc. Now similar to mould mould sandwiches what has been adopted generally ici production technologies,last outer the materials of the epidermis at
64、 moulds and in layers is material different on core occasionally, So two a kind of material person who a certain one inclusives, and core require and have high radiations very, issue and steep shaping and retrieve performance of utilizing etc at 100% by layers of material. Should be fixed relatively
65、 by the excellent choice to select the material for use. After injecting the shaping technology and come out in 15 altogether, can really just popularize and popularize . One a kind of adoptions inject the thick teeth of shaping fails and produces horizontal cross-section altogether. Material to pac
66、k nylon epidermis, and pearl material pack the nylon at - - glass layers of material core. A rate that shrinks material of pearl of glass is extremely low in core one, have good size stabilities. Nylon prevent pearl from grains of material easy problem of denuding that produces by epidermis person w
67、ho give good and lubricated tooth tooth gear wheel. Already developed several kinds and processed the method of improving new-typly at present on the basis of the basic theory of injecting shaping altogether. At however, in the mould and gas assist paint mould mould. Mould have and paint processing
68、method to adopt low molecular weight polymers as the outer material, Gas assist mould mould shaping to adopt the nitrogen or another kind of gas as the core one( or core ones) material. Produce and process equipment constant to perfect and improve, satisfy of different use newly and the new technolo
69、gies demands with product design, Inject technology and will become the rich and potential industrialized extensive production technology method altogether. Reversal Inject Shaping Comparatively speaking, it is that a relatively new inject shaping chooses parameters that the reversal is injected. Th
70、e greatest difficult point of this technology is lain in when processing the condition suddenly changeses, To the thing that it will be known little about what kind of change behavior plastic melting body will demonstrate . About the rudimentary knowledge of melting body rheology, is not merely the
71、regular shear . Say exactly , the melting body responds( the viscidity and elastic behavior) the characteristic needing expressing, Not only common stable state flow speed or shear speed and temperature, but also including pressure and flow the speed in the twinkling of an eye. These characteristics
72、 including a lot of content and very difficult to understand. However, if not in heterotypic materials inject respect make substantive progress, need and make and publish many kinds of different the concrete operational procedures of plasticses. Need and increase a in common use one tired to try on
73、law is in order to getting ripe and accurate control method also another. During routine inject shaping, the type immobilizes in a of walls, some situations are left, Still utilize and filling on the mould and protect and press and fall section and move the mould wall . Can adopt 2 kinds of differen
74、t methods : Person who move s of perpendicular on dividing into mould line direction wall； Rotate a of walls of the slipping type . Fill stage rotatory type cores with increasing mould. Through this kind of processing technology, the crooked performance and other mechanical performance of making one has gotten great improvement. Polyphenyl drink the water and polypropylene syringe adopt cup the processing method get great to change and break through the ground 2 a piece of products just by second
外文翻譯--注射模具設(shè)計和新型注射成型技術(shù)
