Research on the molding technology of plastic bucket

The influence of equipment structure on product quality The main components of plastic hollow forming machine are extruder and storage head. The extruder must plasticize HMWHDPE powder and recycled pulverized material well, mix evenly, and steadily squeeze into the storage head, through the flow channel of the storage head, squeeze the melt into the storage cylinder, and then injection piston will melt through the mouth mold injection molding. Due to the characteristics of 200 L double ring barrel forming technology, it is required that the billet has uniform viscoelastic energy, good strength of the billet, appropriate wall thickness, and no falling, so the extruder screw and nozzle flow channel structure is very high. The extrusion machine is required to plasticize HMWHDPE powder, and has high efficiency plasticizing unit and mixing unit. The head of the machine needs to use double flow, can make the blank to eliminate fusion mark, reduce stress, make the blank has higher strength, in order to produce high strength products. The SCJ230 hollow machine produced by Suzhou Innovation Packaging Material Co., Ltd. is equipped with an extruder screw diameter of 150 and a length-diameter ratio of 25:1. The barrel of the extruder has a longitudinal groove to improve the solid conveying capacity of plastic. Screw adopts screen screen structure, mixing unit of screw head can make HMWHDPE powder fully plasticized and even mixing. The storage head adopts double flow channel design, the melt into the head is divided into two layers, squeezed into the upper part of the storage cylinder, two layers of melt compression composite layer, and then squeezed into the storage cylinder, the above structure improves the strength of the billet. The axial wall thickness control is the key factor affecting the uniformity of the wall thickness of the hollow forming, and it is also one of the high and new technologies. The unique 64-point axial wall thickness control system developed by Suzhou Innovation Packaging Material Co., LTD is integrated with action sequence control, the wall thickness control is stable, and the actual wall thickness curve is repeatable with the set curve. In addition, it is of practical significance to control the radial wall thickness of the blank. The dressing curve of the die is also different according to the size and structure of the product, so as to ensure the radial wall thickness of the product to meet the requirements. This technology has been widely used in the series of hollow machines of Suzhou Innovation Packaging Material Co., LTD.

Adjustment time, temperature, pressure, speed and other process parameters are the basic elements of plastic processing process control. The factors affecting the properties of hollow blow molding products are more complex, so it is necessary to master the adjustment of various technological parameters, grasp the main contradictions in the factors affecting the temperature setting in the production process, adjust the best technological parameters, produce qualified products and reduce the loss in production. The following is combined with SCD30 hollow machine of Qinchuan Development Co., LTD to discuss the influence of process parameters on product properties. The effect of temperature processing temperature will have a significant effect on the quality of products. When the temperature is too high, the melt viscosity is low, the strength of the billet is small, and the billet is easy to fall, which makes the axial wall thickness control system of the billet meaningless, but also makes the billet yellow, and seriously affects the internal and external quality of the product. When the temperature is too low, the load of the extruder will be increased, the melt viscosity is large, the plasticization is not uniform, the macromolecular chain does not get the necessary relaxation, and the residual stress of the product is large and easy to deformation. SCJ230 hollow machine extruder and head have a total of 12 heating zones, including 6 zones of head and 6 zones of extruder. Temperature setting when DMDY1158 is used for production is shown in the table. The temperature is related to the speed of extruder, and the plasticization of plastic is the result of the joint action of temperature and screw shear. When the machine is started, it mainly depends on heating the plasticized raw materials. When the speed is stable after the extruder is started, it mainly depends on the screw to cut the friction and heat the plasticized raw materials. The setting value of heating temperature at the beginning is about 10 higher than that in normal production. After the speed of extruder is stabilized, it will be reduced to normal. Suitable temperature setting principle is screw torque can not be greatly; Plastic good plasticizing; The billet has certain viscoelasticity and strength without obvious falling