350型復合管螺旋式脫模裝置設計-20t螺旋式脫模裝置【含7張CAD圖帶開題報告-獨家】.zip

350型復合管螺旋式脫模裝置設計-20t螺旋式脫模裝置【含7張CAD圖帶開題報告-獨家】.zip,含7張CAD圖帶開題報告-獨家,350,復合管,螺旋式,脫模,裝置,設計,20,CAD,開題,報告,獨家 資料來源： 文章名：Compression and Transfer Molds 書刊名：《English for Die & Mould Design and Manufacturing》 作 者：JianXiong Liu 出版社：北京大學出版社，2006 章 節(jié)：2.4 Compression and Transfer Molds 頁 碼：P43~P49 文 章 譯 名： 壓縮和轉(zhuǎn)移模具 《模具設計及制造英語》 Compression and Transfer Molds 外文原文： Compression Molding Compression molding is the basic forming process where an appropriate amount of material is introduced into a heated mold, which is subsequently closed under pressure. The molding material, softened by heat, is formed into a continuous mass having the geometrical configuration of the mold cavity. Further heating (thermosetting plastics) results in hardening of the molding material. If thermoplastics are the molding material, hardening is accomplished by cooling the mold. Fig. 2-6 illustrates types of compression molding. Here the molding compound is placed in the heated mold. After the plastic compound softens and becomes plastic, the punch moves down and compresses the material to the required density by a pressure. Some excess material will flow (vertical flash) from the mold as the mold closes to its final position. Continued heat and pressure produce the chemical reaction which hardens the compound. The time required for polymerization or curing depends principally upon the largest cross section of the product and the type of molding compound. The time may be less than a minute, or it may take several minutes before the part is ejected from the cavity. Since the plastic material is placed directly into the mold cavity, the mold itself can be simpler than those used for other molding processes. Gates and sprues are unnecessary. This also results in a saving in material, because trimmed-off gates and sprues would be a complete loss of the thermosetting plastic. The press used for compression molding is usually a vertical hydraulic press. Large presses may require the full attention of one operator. However, several smaller presses can be operated by one operator. The presses are conveniently located so the operator can easily move from one to the next. By the time he gets around to a particular press again, that mold will be ready to open. The thermosetting plastics which harden under heat and pressure are suitable for compression molding and transfer molding. It is not practical to mold thermoplastic materials by these methods, since the molds would have to be alternately heated and cooled. In order to harden and eject thermoplastic parts from the mold, cooling would be necessary. Transfer Molding The transfer molding process consists of placing a charge of material (extrudate or preheated preform) into the chamber, referred to as the pot. The press is activated and travels upward making contact with the floating plate, which closes the two halves of the mold. Further travel of both plates causes contact of the plunger with the material in the pot. Material is then forced through a sprue or sprues directly into the closed cavity. When the cavity is completely filled, the excess material forms a cull in the pot (excess waste material). After the part is cured, the press is opened and the floating plate and bottom plate separate from the top plate, exposing the plunger and cull. As the press travel continues, the floating plate motion is stopped by straps fastened to the top plate. This separates the two halves of the mold, and the part remains in the lower half until knockout pins extract it. Since the process requires that the single charge (shot) of material be transferred from the pot to the cavities, it is known as pot-type transfer (Fig. 2-7). An operator is needed to remove the cull from the pot plunger, remove the part or parts, clean the mold, charge a single shot of preheated material into the pot area, and activate the press. A relatively short time after the patenting of the transfer mold; transfer presses were developed. These consist of a main clamping ram located at either the top or the bottom of the press, with one or more auxiliary rams mounted opposite the clamping ram. The clamping rams activate the movable platen. The auxiliary rams are fastened to the stationary platen and are used to activate a plunger, which moves within a transfer sleeve or cylinder. For the plunger in the bottom half of the mold, the process consists of placing preheated preforms or extrudates in the transfer sleeve or cylinder, closing the two halves of the mold, and activating the plunger, which forces material out through channels, known as runners, and through the restricted gate area into the mold halves. When the cavities are completely filled, the excess material remains as a cull at the face of the plunger. After the material is cured, the press is opened at the parting line, parts are removed and the gate, runner and cull. This molding process is commonly called the plun- ger-transfer method. A typical mold construction is shown in Fig. 2-8. If the bottom plunger- transfer mold is constructed, the operation may be automated, since auxiliary devices may load the preheated preforms, and unloading trays may be utilized to receive and separate the parts, runner, gates, and plunger culls. In all other cases an operator is required for each press. The two-stage plunger transfer process requires a conventionally designed hydraulic or toggle top clamp press, with a bottom transfer cylinder and plunger. A reciprocal screw within a heated barrel is mounted horizontally next to the press. The granular material charge is preheated in the barrel and is discharged into the transfer cylinder or sleeve through an opening in its side. The material flow from the same way as described in the plunger-transfer molding process. The two-stage plunger-transfer molds are similar in construction to the plunger transfer, except that a special transfer cylinder or sleeve and plunger are required. Compression Molds Thermosetting compression-molding compounds can be molded into articles of excellent rigidity and shape retention by supplying heat and pressure. Apart from the molding material, the mold itself is of great importance. Compression molds nowadays are heated electrically exclusively. The mold is loaded with molding compound, by hand, with the aid of a filling device, or with pellets. A construction drawing should be mandatory for every mold to be newly produced. Any new ideas concerning the mold, such as stability of the mold construction, optimum heating, aids to demolding and ejection, e.g., slides, split cavities, cores, etc., can be included in advance and given due consideration. The cost of such drawings will be more than justified as a rule by the ensuing efficient mold production and by fewer alterations and less finishing work on the completed mold. The more accurately details are incorporated in the design, the more finishing work is avoided, e.g., specification of the draft angle required and dimensional tolerances. Because alterations to compression molds are always very expensive, it is of particular importance that the detail drawings be completely clear. The mold must be of sufficiently solid and rigid construction to enable it to withstand the high pressures required with compression molding. The outer walls should be only slightly flexible. If the mold is too flexible, the result could be jamming of the two mold halves on opening, or troublesome ejection. High-walled parts may well exert the total compression a pressure on the side walls. The bottom of the mold must be well supported to absorb the pressure exerted on it and to avoid deflection. As the material costs are comparatively low compared to wages, one can afford to have the mold solidly constructed without incurring any significant increase in cost. The higher steel content ensures a more uniform temperature distribution and temperature control, apart from the greater rigidity. A good polish of the molding areas is absolutely essential for trouble-free ejection and to give a satisfactory surface to the molded article. The mold surface should be glass-hard so that it can withstand the wearing effect the molding material exerts when flowing under pressure and so that it retains its polish. On the other hand, the tool steel needs to possess a tough core, as a slight distortion of the mold walls and the ribs is unavoidable. It is recommended to use a carburizing steel for the shape-giving mold parts. This has already proved itself in the construction of molds for the plastics-processing industry. The mold surface must be resistant to constant attack by chemicals, which is particularly prevalent with certain types of compression-molding compounds. A mold can be protected from chemical attack and frictional wear by chrome plating of the molding surfaces. A further important requirement is that the mold consists of as few interlocking parts as possible. The fitting of several parts into each other is always fraught with danger because of the possible distortion caused by the high compression pressures employed. Should it not be possible to avoid working with inserts, it is then essential that the inserts always be fitted into the compression mold in line with the pressure and never across it. A compression mold basically consists of an upper and a lower part. In normal cases the lower half is fitted to the table of the press and the upper half to the ram. Both mold halves are guided by hardened dowels. Asymmetrical parts cause large one-sided pressure loads to be exerted on the mold. They require compensation through special guides. Ejection usually calls for special equipment. Parts such as flat dishes or plates are easily ejected by compressed air, which is already available on the machine for cleaning flash and material residue from the molds. In all other cases, ejection by ejector pins or ribs is feasible. For parts with a multitude of fibs and openings, ejector pins are essential because of the material shrinkage. Transfer Molds Thermosetting molding compounds can be processed by the transfer molding process. The hot injection cylinder, however, should not contain material reserves for several parts since the material would, only cure in the heat. Thermosets can only be transfer molded if the material volume corresponds to the volume of the part to be produced plus the sprue. It would be expedient to mold with material that has been predried in a high-frequency oven, to be taken out of the oven only just before it is metered into the transfer cylinder. The most favorable and most accurate type of metering in this case——as with conventional compression moldingis——also achieved with precompressed pellets. As they are already of a certain density, greater leeway can be given to the dimensions of the injection cylinder, which has a decisive influence on the injection pressure required. Because the material is injected through a small nozzle bore very uniform heat permeation is achieved. Whereas in compression molding-even with well prewarmed pellets——the material does not flow very easily, thoroughly plasticized material enters the cavities in transfer molding. The material is additionally warmed by the heated mold walls. Heat permeation is therefore better than with compression molding. A considerably shorter cure time is needed for the transfer molding process than for the compression molding method. The transfer molding process also is of particular advantage when long cores have to be employed due to the nature of the parts. In this instance, their guidance and support against unilateral pressure is considerably easier to design than for compression molding. This is also the reason why injection around sensitive metal parts is possible. The cores and the inserts must be advantageously positioned in the flow path of the material by arranging the runners accordingly. The requirements to be met by a transfer mold are basically the same as those for a compression mold. Due to the injection pressure required, which lays around 1,000 to 1,800 bar in the injection cylinder but is somewhat lower inside the mold cavity, although still higher than with ordinary compression molding, the mold must be more solidly constructed. Particular care must be taken with the venting of the shape-giving cavities as the mold is already fully clamped during injection. If this is not observed, voids and incomplete parts will result in the same manner as can be experienced when injection molding thermoplastics material. However, as venting of the mold is not possible in the same way as it is done on standard compression molds, air vents have to be positioned and dimensioned so that they permit the gases to escape from the material without allowing the latter to clog up the venting channels. The construction of a transfer mold differs from that of a compression mold in that the charging chamber does not exist. This has been replaced by an injection cylinder and piston positioned in the center of the mold. One differentiates between the two basic types of transfer mold as follows: transfer mold with top injection cylinder and piston. These molds can be operated on standard presses, in which case the restriction in the opening stroke has of course to be taken into consideration. Transfer mold with bottom injection cylinder and piston. For molds of this type of construction a press with a separate injection unit is compulsory. This is usually a press with a hydraulic cylinder mounted centrally underneath the mold table to operate the injection piston, which is interlocked with the timers on the machine (transfer molding). The shape-forming mold parts and cavities are executed in the same manner as those on standard compression molds.  壓縮和轉(zhuǎn)移模具 譯文： 壓縮成型 壓縮成型是基本的成型過程，其中將適量的材料引入加熱的模具中，隨后在 壓力下將其關閉。 通過加熱軟化的模制材料形成具有模腔幾何構(gòu)型的連續(xù)物質(zhì)。 進一步加熱（熱固性塑料）導致模塑材料硬化。如果熱塑性塑料是模塑材料，則通過冷卻模具來完成硬化。 圖 2-6 顯示了壓縮成型的類型。這里將模塑料放置在加熱的模具中。塑料復合物軟化并變成塑料后，沖頭向下移動并通過壓力將材料壓縮到所需密度。當 模具接近其最終位置時，一些多余的材料將從模具流出（垂直閃光）。 持續(xù)的熱量和壓力產(chǎn)生使化合物硬化的化學反應。聚合或固化所需的時間主要取決于產(chǎn)物的最大橫截面和模塑料的類型。時間可能不到一分鐘，或者可能需要幾分鐘時間才能將零件從腔體中彈出。 由于塑料材料直接放入模腔內(nèi)，所以模具本身可以比用于其他模塑工藝的模 具更簡單。Gates和sprues是不必要的。這也節(jié)省了材料，因為修剪的澆口和澆口會完全損失熱固性塑料。用于壓縮成型的壓機通常是立式液壓機。大型印刷機可能需要一位操作員的全面關注。但是，一個操作員可以操作幾臺較小的印刷機。 這些印刷機位置便利，因此操作員可以輕松地從一個移動到另一個。當他再次接觸特定媒體時，該模具將準備打開。 在熱和壓力下硬化的熱固性塑料適用于壓縮成型和傳遞模塑。用這些方法模塑熱塑性材料是不實際的，因為模具必須交替加熱和冷卻。為了硬化并從模具中排出熱塑性部件，需要冷卻。 傳遞模塑 傳遞模塑工藝包括將一定量的材料（擠出物或預熱的預成型件）放入稱為鍋 的腔室中。壓機啟動并向上移動，與浮動板接觸，從而關閉模具的兩半。 兩個板的進一步行程導致柱塞與罐中的材料接觸。然后材料被迫直接通過澆口或澆口進入封閉的空腔。當空腔被完全填滿時，多余的材料在罐中形成剔除（多余的廢料）。部件固化后，打開壓機，浮板和底板與頂板分離，露出柱塞并剔除。隨著印刷機行程的繼續(xù)，浮板運動通過固定在頂板上的帶子停止。 這將模具的兩個半部分分開，并且該部分保持在下半部分，直到挖空銷拔出。 由于該工藝要求材料的單次裝料（噴丸）從罐轉(zhuǎn)移到腔，所以稱為罐式轉(zhuǎn)移（圖 2-7）。操作人員需要從痰壺柱塞上取下剔除器，取下零件或部件，清潔模具，將預熱材料注入罐區(qū)并啟動壓機。 在轉(zhuǎn)移模具申請專利之后相對較短的時間; 轉(zhuǎn)印機開發(fā)。 它們包括一個位于壓力機頂部或底部的主夾緊滑塊，一個或多個輔助滑塊安裝在夾緊滑塊對面。 夾緊頂桿激活可移動壓板。輔助壓頭固定在固定壓板上，用于啟動一個柱塞，該柱塞在傳輸套筒或氣缸內(nèi)移動。對于模具下半部的柱塞，該過程包括將預熱的預成型件或擠出物放置在傳送套筒或圓筒中，關閉模具的兩半，并啟動柱塞，該柱塞迫使材料通過通道被稱為流道，并通過限制的門區(qū)進入半模。當空腔完全填充時，多余的材料在柱塞的表面保持為剔除狀態(tài)。材料固化后，壓機在分模線處打開，零件被移除，澆口，澆道和剔除。這種成型工藝通常被稱為浸入式轉(zhuǎn)移法。 典型的模具結(jié)構(gòu)如圖 2-8 所示。如果底部柱塞傳遞模具被構(gòu)造，則操作可以是自動的，因為輔助裝置可以裝載預熱的預成型件，并且卸載盤可以用于接收和分離部件，流道，閘門和柱塞剔除。在所有其他情況下，每臺印刷機都需要操作員。 兩級柱塞傳送過程需要傳統(tǒng)設計的液壓或肘節(jié)頂部夾鉗壓力機，帶有底部傳 送滾筒和柱塞。加熱桶內(nèi)的往復螺絲水平安裝在印刷機旁邊。顆粒物料在料筒中被預熱，并通過其側(cè)面的開口排入轉(zhuǎn)移圓筒或套筒。材料以與柱塞傳遞模塑工藝中所述相同的方式流動。 兩級柱塞傳輸模具的結(jié)構(gòu)與柱塞傳輸相似，只是需要特殊的傳輸圓柱體或套 筒和柱塞。 圖2-7熱固器的罐型或澆口型傳熱成型 圖2-8熱固性塑料柱塞傳遞成型 壓縮模具 通過提供熱量和壓力，熱固性壓縮模制化合物可以模制成具有優(yōu)異剛性和形 狀保持的制品。除了成型材料外，模具本身也非常重要。 當今的壓縮模具僅通過電加熱。手工借助填充裝置或顆粒將模具裝載模塑 料。 對于每個新生產(chǎn)的模具都應該強制施工圖紙?？梢灶A先考慮關于模具的任 何新觀點，例如模具結(jié)構(gòu)的穩(wěn)定性，最佳加熱，輔助脫模和噴射，例如載玻片， 分裂腔，型芯等。通過高效的模具生產(chǎn)以及對完成的模具進行更少的改造和更少的精加工工作，這些圖紙的成本將超過合理程度。 更精確的細節(jié)被納入設計中，避免了更多的精加工工作，例如規(guī)定所需的拔模角度和尺寸公差。 由于對壓縮模具的改造總是非常昂貴，因此細節(jié)圖完全清晰是特別重要的。 模具必須具有足夠堅固和剛性的結(jié)構(gòu)，以使其能承受壓縮成型所需的高壓。 外墻應該只是稍微有些彈性。如果模具過于柔軟，則結(jié)果可能是兩個半模在打開時卡住，或者彈出很麻煩。高壁部件可能在側(cè)壁上施加總壓縮壓力。模具的底部必須很好地支撐以吸收施加在其上的壓力并避免撓曲。 由于材料成本與工資相比相對較低，因此可以使模具結(jié)構(gòu)堅固而不會導致成 本顯著增加。除了更高的剛性外，更高的鋼材含量確保更均勻的溫度分布和溫度控制。模塑區(qū)域的良好拋光對于無故障排出以及為模制品提供令人滿意的表面是絕對必要的。模具表面應該是玻璃堅硬的，以便它能夠承受模壓材料在壓力下流動時施加的磨損效應并且因此保持其拋光。另一方面，由于模具壁和肋條的輕微變形是不可避免的，所以工具鋼需要具有堅韌的芯。建議使用滲碳鋼作為賦形模具零件。這已經(jīng)在塑料加工行業(yè)的模具制造中得到了證明。模具表面必須耐受化學物質(zhì)的不斷侵襲，這對于某些類型的壓縮模塑化合物尤其普遍。模具可以通過成型表面的鉻鍍層來防止化學侵蝕和摩擦磨損。 另一個重要的要求是模具由盡可能少的互鎖部件組成。由于所采用的高壓 縮壓力可能導致變形，因此將多個部件相互配合總是充滿危險。如果不能避免使用刀片，那么插入件必須始終與壓力一致地安裝到壓模中，并且永遠不會穿過它。 壓縮模具基本上由上部和下部組成。在正常情況下，下半部分安裝在壓機的工作臺上，上半部分安裝在沖壓機上。兩個半模均由硬化銷釘引導。非對稱部件會在模具上產(chǎn)生較大的單側(cè)壓力負載。他們需要通過特別指南進行賠償。 彈射通常需要特殊設備。平盤或盤子等部件很容易通過壓縮空氣排出，機器上已有該壓縮空氣用于清潔模具上的閃蒸和材料殘留物。在所有其他情況下，可以通過頂針或肋條進行噴射。對于具有多個纖維和開口的零件，由于材料收縮，頂針是必不可少的。 轉(zhuǎn)移模具 熱固性模塑料可以通過傳遞模塑工藝加工。然而，熱注射筒不應該含有多個部件的材料儲備，因為材料只能在熱量中固化。如果材料體積與待生產(chǎn)零件的體積以及澆口相匹配，則熱固性塑料只能進行傳遞模塑。用已經(jīng)在高頻爐中預干燥的材料進行模制將是有利的，僅在其被計量到傳送滾筒中之前才從烘箱中取出。 在這種情況下，最有利和最準確的計量類型——與傳統(tǒng)壓縮成型一樣——也 可通過預壓縮顆粒實現(xiàn)。由于它們已經(jīng)具有一定的密度，所以可以給注射缸的尺寸帶來更大的余地，這對注塑壓力具有決定性的影響。由于材料通過小噴嘴孔注入，所以可以實現(xiàn)非常均勻的熱滲透。而在壓縮成型中——即使預熱好的丸?！牧弦膊灰琢鲃樱耆芑牟牧显趥鬟f模塑中進入腔體。材料另外被加熱的模具壁加熱。因此，熱滲透優(yōu)于壓縮成型。傳遞模塑工藝所需的固化時間要比壓縮模塑法短得多。由于部件的性質(zhì)，必須使用長芯時，傳遞模塑工藝也是特別有利的。在這種情況下，他們對單向壓力的指導和支持比壓塑更容易設計。這也是為什么可能在敏感金屬部件周圍注射的原因。通過相應地布置滑道，芯和插入件必須有利地定位在材料的流動路徑中。 傳遞模具所要滿足的要求與壓縮模具的要求基本相同。由于所需的注塑壓 力在注塑缸中的壓力約為1,000至1,800 巴，但在模腔內(nèi)稍低，雖然仍高于普通壓縮成型，但模具的結(jié)構(gòu)必須更牢固。由于模具在注射過程中已經(jīng)被完全夾緊， 因此必須特別注意形狀賦予腔的排氣。如果沒有觀察到，空隙和不完整的部件將導致與注塑熱塑性塑料材料時所經(jīng)歷的相同的方式。但是，由于不能像在標準壓縮模具上那樣進行模具的排氣，所以必須定位和確定通風孔的尺寸，使得氣體能夠從材料中逸出而不會使材料堵塞通風管道。 傳送模具的構(gòu)造與壓縮模具的構(gòu)造的不同之處在于不存在填充室。這已被 位于模具中心的注射缸和活塞所取代。一種是根據(jù)以下兩種基本類型的傳遞模 具進行區(qū)分：用頂部注射缸和活塞傳遞模具。這些模具可以在標準壓力機上操作，在這種情況下，打開沖程的限制當然要考慮在內(nèi)。 用底部注射缸和活塞傳輸模具。對于這種結(jié)構(gòu)的模具，必須使用帶有單獨注射裝置的壓力機。這通常是一臺帶有液壓缸的壓力機，液壓缸安裝在模具臺下方的中央，用于操作與機器上的定時器（傳遞模塑）互鎖的注射活塞。成型模具部件和模腔的加工方式與標準加壓模具相同。 15