The most noteworthy new technologies in twin-screw pelletizers/plastic pelletizing machines in 2016

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This post was last edited by ljtjbx on 2016-10-19 09:05. The most noteworthy new technologies in twin-screw granulators/plastic granulating machines in 2016 include parallel-coaxial twin-screw extruders, which are widely used in applications such as plastic modification, plastic coloring, and plastic reinforcement. Currently, domestic twin-screw extruders encounter various problems during the production process. Many customers encounter various questions when using twin-screw extruders; for example, why are the physicochemical properties of the pellets unstable during production? The modified particles suffered from charring and poor plasticization, as well as the formation of lumps; the color masterbatches showed uneven coloring, and during the production of high-fill masterbatches, the filling components sprayed out ； The formula needs to be adjusted continuously during production ； Particle defects are becoming increasingly severe ； The screw accessories wear out quickly, requiring frequent replacement ； Issues such as rising formula costs instead of a decrease, and so on, have led Meihu Plastic Machinery to develop the following theories in response to these customer concerns; these theories are then applied in the design of extruders. Four invention patents and twelve utility model patents have been filed. Question 1: Decline in the physical properties of the product: When the plastic melt is extruded, the excessive gap between the screw and the barrel of traditional extruders results in significant backflow, causing the various components in the formula to be sheared repeatedly. This excessive shearing generates a lot of internal shear heat, which damages the components of the formula to varying degrees – for example, it leads to the premature decomposition and evaporation of certain substances. Question 2: Particle defects (particles with pores, flow marks, scars, low yield, high power consumption): Backflow of the melt due to a large extrusion gap reduces the screw’s extrusion capacity per unit time; 1: Low die pressure ； This results in the particles not being dense. 2: Low yield ； Backflow causes repeated shearing, inadvertently consuming excessive electrical energy and increasing the granulation cost. MeiHu 50 model, 55 KW; actual production capacity at a ratio of 44:1: the material used for testing was PP–MR1600 ； With a specific gravity of 0.9, normal production can achieve a yield of 280 Kg/H, and the electricity cost is 100–160 yuan per ton. Question 3: The surface of the particles is not shiny; it is difficult to clean the screw when changing the material, and the barrel gets clogged due to rust. The barrel is a key component of the extruder, and Meihu Plastic Machinery has significantly improved the precision of the flow channels within the extrusion system. Both the barrel and the screw are made from special alloys designed for use in high-quality plastic machinery. The surface finish can reach a mirror-like quality, which reduces the frictional resistance during the advancement of the melt. It also facilitates color change and cleaning, making it an essential requirement for the production of colored masterbatches and high-demand plastic masterbatches. Regarding the cooling of the cylinder, the Meihu plastic machine employs a dual-channel oil cooling system, which not only prevents sudden cooling of the cylinder but also reduces the buildup of carbon deposits and rust blockages in the cooling holes of the cylinder. MeiHu Company is the only enterprise in China to use specialized materials for mirror plastic in a full extrusion system. The extruder barrel, screw, die head, and strip outlet plate, as well as its internal cavity, are all made of a seamless mirror-like material. (Non-chromed) Question 4: Poor dispersion of the powder: The arc shape of the threaded sleeve tends to be at the theoretical design value ； It minimizes the kneading space to the greatest extent, thereby enhancing the mixing performance of the threaded sleeve ； Application analysis: For example, in the case of two types of white masterbatches, PP and PET, it is required that not only should they be well dispersed, but their viscosity also needs to be high. Excessive shearing will indeed improve dispersion, but it will reduce viscosity, thereby directly affecting the coloring effect during spinning. Issue 5: The physical and chemical properties do not meet the requirements: Too much shear leads to increased shear heat within the material, resulting in a decline in physical properties and failure to meet the required chemical properties. Since twin-screw extruders are composed of interlocking screw elements, the length-to-diameter ratio of the screws used for producing color masterbatches is generally high (for model 50, it ranges from 44:1 to 48:1) ； 2090-2280MM). The mandrel that positions the threaded sleeves is usually positioned using involute tooth profiles; therefore, the linear positioning accuracy of the mandrel is particularly important. It determines whether the phases of the first and last threaded sleeves in the screw assembly can align on a straight line, which in turn affects the effectiveness of the Archimedean spiral engagement between the threaded sleeves on the two screws ； If the precision is not high, the clamping effect of the threaded sleeve will be lost; in such cases, increasing the number of clamping elements is necessary to achieve a sufficient shearing effect. However, too many clamping elements not only increase resistance but also generate excessive shear heat, which can lead to the decomposition of the raw materials and the loss of components in the formula, thereby compromising the material properties. Based on the problems that arise during customers’ production processes, our company continuously improves the design of its extruders. To date, our Type B extruders have been on the market for nearly four years, and they have received unanimous approval from our clients. Please believe, friends, that a good extruder is key to ensuring the success of a formula; it is also crucial for saving costs. Mei Hu Plastic Machinery creates high-quality plastic machinery for customers with sincerity and dedication. With serving customers as our original intention, we take customer satisfaction as our responsibility.