Calcium plastic hollow grid sheet
DATE：2021/9/10 8:29:41 / READ： / SOURCE：This station
Calcium plastic hollow grid sheet
The calcium-plastic hollow grid board used in the production of packaging boxes is produced by extrusion method. It is made of high-density PE resin as raw material, calcium carbonate as filler and surface activation treatment, through plasticization, granulation, and extrusion molding
2. Main equipment
(1) Double screw or single screw extruder
(2) Nose
It is not difficult to see from the structure, shape and size of the calcium-plastic hollow grid board. It belongs to a special profile with a width, a wall and a space in the middle, so its molding head should be in line with the extrusion of the board (sheet). The machine head is similar, and the shape is flat; but the internal structure should be the same as that of the profiled machine head, with a split cone and a core mold support. Because the flow channel changes greatly, the expansion angle of the branch pipe is logarithmic with the die width, and the design and size calculation of the flow channel are very complicated. It is difficult to make the flow rate and pressure of the material equal across the entire width of the die above 1200m to achieve consistent discharge. Although the textbooks and related materials introduce the design of the board head with a width greater than 700m, the design of the distributing screw structure should be considered, but in order to simplify the structure and reduce the manufacturing cost of the head, it is bold to adopt a hanger-type structure with gradual branch pipes. Designed this kind of hollow special-shaped board head as shown in Figure 2-39. After repeated revisions, qualified products were trial-produced. The head has the following characteristics
1) The structure is simple, compact, reasonable, easy to process, and low in manufacturing cost;
2) Equipped with flow resistance adjustment device and buffer zone to ensure the uniform flow rate of the material;
3) Through the adjustment of the core mold, the upper and lower discharge rooms can be adjusted
4) The temperature control of the front and rear sections and the left, middle and right sections of the heating device are carried out in the partition section, and the distribution is reasonable
5) The template has high strength, reasonable distribution of connecting screws, and no overflow on the parting surface
6) The upper and lower templates are positioned accurately, which facilitates the assembly, disassembly and cleaning of the machine head.
(3) Auxiliary machine design
As we all know, the auxiliary machinery of the board (sheet) material production line is generally composed of three-roll calender, tractor and cutting device. Obviously, it is absolutely impossible to use this general-purpose board auxiliary machine to produce calcium-plastic hollow grid boards. Therefore, the developer designed a special shaft machine
1) Shaping device. According to the principle of profile extrusion molding, a setting device with a width of 1600m and a length of 3400mm is designed. On this sizing table that can move back and forth, a set of vacuum adsorption sizing molds and two food cooling sizing molds as shown in Figure 2-40 are also installed. Seven grooves are arranged in the upper and lower templates of the vacuum setting template, of which the first groove is an air groove; the second, fourth, and sixth grooves are vacuum adsorption grooves; the third, fifth, and seventh grooves are water grooves. Compressed air is blown out from the oblique seam at the front end of the air groove to cool the blank that has just left the die of the machine head, so that the surface of the blank is quickly cooled, and the molten material is prevented from sticking to the setting plate or vacuum suction due to the production line of the product. The speed is faster. After the plastic hollow grid board is vacuum shaped, it can only be initially shaped, but it is not completely cooled. In order to prevent its warping and deformation, two sets of cooling shaped boards with a width of 400mn are specially set up to continue flat pressing of the products. Cooling to ensure the quality of the product.
2) Traction device. The common plate (sheet) material tractor not only has a small number of rubber rollers, but also generally uses the lower roller as the driving force, and the upper roller is driven by pressing the plate tightly. But the hollow plastic grating board cannot withstand greater pressure, otherwise its vertical ribs will all be overwhelmed, which will affect the appearance and strength of the product. However, if it is not pressed tightly, the product will slip between the two rubber rollers and affect normal production due to the traction being less than the suction force generated by the vacuum.
Therefore, a tractor with six pairs of rubber rollers is specially designed, and the upper and lower rollers are all driven by sprockets and chains, which increases the friction force of the rubber rollers on the products.
Author：admin