I. Extruder classification Product code Specification p […]
I. Extruder classification Product code Specification parameter description: For example, SHJM-Z40×25×800, the screw diameter is 40mm, the aspect ratio is 25, and the length of the traction roller is 800mm. The twin-screw hybrid plastic extrusion modified film machine. 1, "SH" category code, refers to the twin-screw hybrid type (also written: SHSJ, SJ refers to the plastic extruder) 2, "J" group code, refers to the extruder. 3, "M" refers to the variety code, refers to the blown film machine 4, "Z" refers to the auxiliary code, refers to the main unit, and if the "F" refers to the auxiliary machine. 5. “40×25×800” refers to the specification parameters, which means that the screw has a diameter of 40 mm, a length to diameter ratio of 25, and a traction roller length of 800 mm. 6. The last digit is the manufacturer identification serial number, which generally does not appear, and is omitted. 2.
The function parameters of the twin-screw mixing extruder 1. “D” is the diameter, an important parameter to measure the output size. 2, "L / D", refers to the ratio of length to diameter, directly affects the degree of plasticization, is a measure of the use of the general plastic modification, with 30-40 or so, commonly used 36:1 or 30:1. 3, "H", the depth of the groove, refers to the size of its volume. 4, "e" spiral thickness, the process is reflected in the size of the shear. 5, the gap between the "6" screw and the barrel, an important parameter of the extruder quality, generally 0.3-2mm, over the 5mm extruder is the police line. 6. “N” main engine speed refers to its highest value, which refers to a processing adjustment range, which greatly affects the division of production and medium and high speed. (Domestic machine is generally 500-600r/min) Such as: max: 600r/min, low speed: 350r/min, medium speed 230-240r/min, high speed 450-600r/min. 7, "P", motor power and heating power. Third, the screw arrangement and its process setting 1 segmentation of the screw and its function (1) the screw is generally divided into five sections: conveying section, melting section, mixing section, exhaust section and homogenization section. 1. Conveying section, conveying materials to prevent flashing. 2.
The melting section, which is fully melted and homogenized by heat transfer and friction shearing. 3, the mixing section, the material composition size is further refined and uniform, forming an ideal structure, with a distribution and dispersion mixing function. 4. The exhaust section discharges impurities such as water vapor and low molecular weight substances. 5, homogenization (metering) section, conveying and pressurization, establish a certain pressure, so that the material at the die has a certain density, and at the same time further mixing, and finally achieve the purpose of smooth extrusion granulation. (2) Distribution (distribution) and dispersion mixing section 1, distribution and mixing, so that the melt is divided and recombined, so that the spatial distribution of each component is uniform, mainly through separation, stretching (alternative compression and expansion), distortion, fluid It is realized by displacement flow under the action of stress reorientation. 2. Disperse mixing to break the components into fine particles or to make the incompatible two-component dispersed phase reach the required range, mainly by shear pressure and tensile stress. 2 conveying elements, threaded • Representation: For example, “56/56” conveying block, the previous “56” guiding process is 56MM, and the latter “56” refers to the length of 56MM. • Large lead, which means the pitch is 1.5D~2D • Small lead, which means the pitch is about 0.4D.
The law of use: As the lead increases, the amount of screw extrusion increases, the residence time of the material decreases, and the mixing effect decreases.
A. When large lead thread is used, it is beneficial to increase the output in the case of conveying; heat sensitive polymer, shortening the residence time and reducing degradation; exhausting, selecting (also using shallow groove), increasing surface area, which is beneficial to Exhaust, volatilize, etc. • B. In the case of medium lead thread, in the case of mixing, the combination of different working sections is gradually reduced for conveying and pressurization. • C. When a small lead thread is selected, it is generally reduced in combination, used for conveying section and homogenizing metering section, which acts to pressurize and improve melting; to improve the degree of compounding and extrusion stability. 3 mixing components, there are two categories, "K" series and "M" series (toothed) • "K" series • notation: such as K45/5/56", belonging to the cut block, with "K" Sheet-shaped cutout, "45" refers to the angle of the piece, "5" refers to a total of 5, "56" refers to the length of 56MM, the width of the spiral edge is 56/5 = 11.2mm), its parameters: • A, Direction, there are forward and reverse - reverse, which hinders the material transport, prolongs the time, increases the filling and increases the pressure, and greatly improves the mixing effect. • B, angle, generally “30° 45 °, 60 °, 90 °", its effects and effects: • a, positive, increase the stagger angle, will reduce the transport capacity, extend the residence time, improve the mixing effect, but the more easy to leak. For distributed mixing and dispersion mixing, the distribution mixing is more effective with a larger angle, and the dispersion is mixed at an angle of 45. The best is followed by 30. The worst is 60. • b. In the reverse direction, increase the angle. Will reduce the effective limit of the polymer, but the more easy to leak. • C, the width of the spiral edge is generally 7mm, 11mm, 11.2mm, 14m m, 19mm, etc., which is one of the most important parameters to measure the size of the shear and the size of the mixture.
The larger the width, the larger the shear, the smaller the mixing; the smaller the width, the smaller the shear, the larger the mixing. For the mixing and dispersion of the distribution In terms of mixing, the distribution is mixed, the effectiveness is reduced as the width is increased, and the dispersion mixing increases in effectiveness with increasing width; the smaller the width, the larger the ratio of the axial effective flow rate to the radial effective flow rate of the material. The number of heads, generally single head, double head, three heads. Its effect: • a, in the positive direction, the fewer the number of heads, the greater the extrusion conveying capacity, the greater the torque, the better the mixing characteristics, but the cutting The less the effect. • b. In the reverse direction, the fewer the number of heads, the smaller the extrusion conveying capacity and the better the mixing characteristics. • c.
