everplast:extruder_machine
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| - | 這裡是指塑料押出機也稱[[https:// | + | Plastics extrusion is a high-volume manufacturing process in which raw plastic is melted and formed into a [[https:// |
| - | {{ : | + | {{ : |
| - | 這過程先是將[[https:// | + | |
| - | ===== 押出機歷史 ===== | + | This process starts by feeding [[https:// |
| - | 押出機的發產可追溯到 19 世紀早期。在 1820 年， Thomas Hancock 發明了一種橡膠“咀嚼器”，用於回收加工過的橡膠廢料，到 1836 年， Edwin Chaffee 開發了一種雙螺桿加工機，將添加劑混合到橡膠中。((Tadmor and Gogos (2006). ' | + | |
| - | ===== 運作流程 | + | ===== History |
| - | 在塑料押出中，原料化合物材料通常為樹脂的形式，原料從押出機頂部所安裝的料斗透過重力進料到押出機的料筒中。通常會使用添加劑如著色母和UV抑製劑（液體或棵粒形式），並且在到達料斗之前透過混料機將其混合到原料中。從押出機技術的觀點來看，這方法與塑料射出成型有許多共同之處，儘管它的不同之處在於它通常是連續的方式。主要差異是押出成型是透過引取與押出透過模具可連續的產生了固定長度許多相似的外形成品，依據不同塑料的物性添加成型需要的配方增強劑，調整模具成型條件的引取拉動或押出速度來實現。 | + | |
| - | 材料通過入料孔（靠近料管後部的開口）進入料管並與螺桿接觸。旋轉螺桿（例如 120 rpm 轉速轉動）使塑料向前進入螺桿料管加熱溶融段。由於粘性加熱和其他影響，所需的押出溫度很少等於料管的設定溫度。在大多數過程中，為料管設置加熱曲線，其中三個或更多個獨立的 PID 來控制加熱器區域, 從後段（塑料進入的地方）逐漸增加料管的溫度到前段。這樣的方式可以讓塑料在螺桿推送過程中逐漸熔化並降低過熱的風險，因為過熱的溫度可能導致塑料聚合物燒焦裂解。 | + | The first precursors to the modern extruder were developed in the early 19th century. In 1820, Thomas Hancock invented a rubber " |
| - | 料管內的強烈壓力和摩擦會產生額外的熱量。實際上，對於某些塑料如果押出生產線能夠快速運行，則可以關閉加熱器並且僅通過料管內的壓力和摩擦來保持熔體溫度。但在大多數押出機中，如果產生過多的熱量，則需要透過冷卻風扇來將溫度保持在所設定的溫度以下。如果強制空氣冷卻不足以降溫，則須改用鑄入式冷卻套來解決。 | + | ===== Process ===== |
| - | 在料管的前段，熔化的塑料離開螺桿並穿過篩網組件以去除熔體中的任何污染物。由於此時的壓力可超過 5,000 psi（34 MPa），因此篩網由一個粉碎板（一個帶有許多鑽孔的厚金屬圓盤）固定。篩網組件/ | + | In the extrusion of plastics, the raw compound material is commonly in the form of nurdles (small beads, often called resin) that are gravity fed from a top mounted hopper into the barrel of the extruder. Additives such as colorants and UV inhibitors (in either liquid or pellet form) are often used and can be mixed into the resin prior to arriving at the hopper. The process has much in common with plastic injection molding from the point of the extruder technology, although it differs in that it is usually a continuous process. While pultrusion can offer many similar profiles in continuous lengths, usually with added reinforcing, |
| - | 在通過粉碎板後，熔融塑料進入模具。模具是要產生最終產品的輪廓，必須設計成使熔融塑料從圓柱形輪廓均勻地流到產品的輪廓形狀。在該階段的不均勻流動會在型材中的某些點產生非預期的殘餘應力產品，這可能會造成冷卻後型材成品出現翹曲現象。押出機的模具主要是用來創建各種可連續產生的成品形狀輪廓, 如果無法連續產生的成品型狀, | + | The material enters through the feed throat (an opening near the rear of the barrel) and comes into contact with the screw. The rotating screw (normally turning at e.g. 120 rpm) forces the plastic beads forward into the heated barrel. The desired extrusion temperature is rarely equal to the set temperature of the barrel due to viscous heating and other effects. In most processes, a heating profile is set for the barrel in which three or more independent PID-controlled heater zones gradually increase the temperature of the barrel from the rear (where the plastic enters) to the front. This allows the plastic beads to melt gradually as they are pushed through the barrel and lowers the risk of overheating which may cause degradation in the polymer. |
| - | 接下來就必須考慮冷卻出模具後的成品，通常會讓押出的成品經過冷卻水槽來實現。塑料是非常好的熱絕緣體，因此很難快速冷卻。與鋼相比，塑料的熱量傳導速度要慢 2000 倍。在管材押出生產線中，管材成品經過精心控制的真空密封水槽加以冷卻，以保持新形成尚未凝固的管材成品不會塌陷。對於諸如塑料薄膜的產品，通過拉動一組冷卻輥輪來實現冷卻。對於薄膜和非常薄的薄片，空氣冷卻作為初始冷卻階段是有效的，如在吹膜押出中。 | + | Extra heat is contributed by the intense pressure and friction taking place inside the barrel. In fact, if an extrusion line is running certain materials fast enough, the heaters can be shut off and the melt temperature maintained by pressure and friction alone inside the barrel. In most extruders, cooling fans are present to keep the temperature below a set value if too much heat is generated. If forced air cooling proves insufficient then cast-in cooling jackets are employed. |
| - | 塑料押出機還廣泛用於在清潔，粉碎和/或混合後再加工回收的塑料廢料或其他原料。通常將該材料押出成適於切成棵粒或原料的長條，以用作進一步加工的前置作業。 | + | At the front of the barrel, the molten plastic leaves the screw and travels through a screen pack to remove any contaminants in the melt. The screens are reinforced by a breaker plate (a thick metal puck with many holes drilled through it) since the pressure at this point can exceed 5,000 psi (34 MPa). The screen pack/breaker plate assembly also serves to create back pressure in the barrel. Back pressure is required for uniform melting and proper mixing of the polymer, and how much pressure is generated can be " |
| - | ===== 螺絲設計 ===== | + | After passing through the breaker plate molten plastic enters the die. The die is what gives the final product its profile and must be designed so that the molten plastic evenly flows from a cylindrical profile, to the product' |
| - | 熱塑性螺桿有五個可能的區域。由於術語並未標準化，因此可能會有不同的名稱指這些區域。不同類型的塑料聚合物將具有不同的螺桿設計，有些可能不會包含所有可能的區域。 | + | The product must now be cooled and this is usually achieved by pulling the extrudate through a water bath. Plastics are very good thermal insulators and are therefore difficult to cool quickly. Compared to steel, plastic conducts its heat away 2,000 times more slowly. In a tube or pipe extrusion line, a sealed water bath is acted upon by a carefully controlled vacuum to keep the newly formed and still molten tube or pipe from collapsing. For products such as plastic sheeting, the cooling is achieved by pulling through a set of cooling rolls. For films and very thin sheeting, air cooling can be effective as an initial cooling stage, as in blown film extrusion. |
| - | 大多數螺釘都有這三個區域： | + | Plastic extruders are also extensively used to reprocess recycled plastic waste or other raw materials after cleaning, sorting and/or blending. This material is commonly extruded into filaments suitable for chopping into the bead or pellet stock to use as a precursor for further processing. |
| - | * 進料區（也稱為固體輸送區）：該區域將樹脂送入押出機，整個區域的通道深度通常相同。 | + | ===== Screw design ===== |
| - | * 熔化區（也稱為過渡區或壓縮區）：大部分聚合物在此部分熔化，並且通道深度逐漸變小。 | + | |
| - | * 計量區（也稱為熔體輸送區）：該區熔化最後的顆粒並混合至均勻的溫度和組成。與進料區一樣，通道深度在整個區域內保持恆定。 | + | |
| - | 此外，通風（兩級）螺桿具有： | + | There are five possible zones in a thermoplastic screw. Since terminology is not standardized in the industry, different names may refer to these zones. Different types of polymer will have differing screw designs, some not incorporating all of the possible zones. |
| - | * 減壓區。在這個區域，大約三分之二的螺桿，通道突然變得更深，這減輕了壓力，並允許任何被困氣體（水分，空氣，溶劑或反應物）通過真空抽出。 | + | Most screws have these three zones: |
| - | * 第二個計量區。該區域與第一個計量區域類似，但通道深度更大。它可以使熔體再加壓，使其通過篩網和模具的阻力。 | + | |
| - | 螺桿長度通常以其直徑為 L:D 比率。例如，直徑為6英寸（150毫米），螺桿尺寸為24：1，長度為144英寸（12英尺），32：1長度為192英寸（16英尺）。 L:D 比率為25：1是常見的，但是一些機器可以達到40：1以獲得更多混合，並且在相同螺桿直徑下輸出更多。兩級（通風）螺桿通常為36：1以考慮兩個額外區域。 | + | * Feed zone (also called the solids conveying zone): this zone feeds the resin into the extruder, and the channel depth is usually the same throughout the zone. |
| + | * Melting zone (also called the transition or compression zone): most of the polymer is melted in this section, and the channel depth gets progressively smaller. | ||
| + | * Metering zone (also called the melt conveying zone): this zone melts the last particles and mixes to a uniform temperature and composition. Like the feed zone, the channel depth is constant throughout this zone. | ||
| - | 每個區域在料管中配備一個或多個熱電偶或 RTD 用於溫度控制。' | + | In addition, a vented (two-stage) screw has: |
| + | * Decompression zone. In this zone, about two-thirds down the screw, the channel suddenly gets deeper, which relieves the pressure and allows any trapped gases (moisture, air, solvents, or reactants) to be drawn out by vacuum. | ||
| + | * Second metering zone. This zone is similar to the first metering zone, but with greater channel depth. It serves to repressurize the melt to get it through the resistance of the screens and the die. | ||
| - | ===== 典型壓出機使用原料 ===== | + | Often screw length is referenced to its diameter as L:D ratio. For instance, a 6-inch (150 mm) diameter screw at 24:1 will be 144 inches (12 ft) long, and at 32:1 it is 192 inches (16 ft) long. An L:D ratio of 25:1 is common, but some machines go up to 40:1 for more mixing and more output at the same screw diameter. Two-stage (vented) screws are typically 36:1 to account for the two extra zones. |
| - | 用於押出的典型塑料材料包括但不限於：聚乙烯（PE），聚丙烯，乙縮醛，丙烯酸，尼龍（polyamides），聚苯乙烯，聚氯乙烯（PVC），丙烯腈丁二烯苯乙烯（ABS）和聚碳酸酯。((Todd, | + | Each zone is equipped with one or more thermocouples or RTDs in the barrel wall for temperature control. The " |
| - | ===== 參考網址 | + | ===== Typical extrusion materials ===== |
| - | * [[https:// | + | |
| + | Typical plastic materials that are used in extrusion include but are not limited to: polyethylene (PE), polypropylene, | ||
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| + | |||
| + | ===== Reference URL ===== | ||
| + | * https:// | ||
| * https:// | * https:// | ||
| - | {{tag>押出機 壓出機 | + | {{tag>Plastics |
everplast/extruder_machine.1565676810.txt.gz · Last modified: 2019/08/13 06:13 by jonathan_tsai