Molding technology for controlling wall thickness distribution of hollow blow-molded product through inflation pressure

Abstract

The invention relates to the technical field of hollow blowing molding, in particular to a molding technology for controlling wall thickness distribution of a hollow blow-molded product through inflation pressure. According to the technological condition, the temperature of a bush die ranges from 170 DEG C to 200 DEG C, and the temperature of a material barrel is divided into five segments, wherein the temperature of the first segment is 165 DEG C, the temperature of the second segment is 170 DEG C, the temperature of the third segment is 170 DEG C, the temperature of the fourth segment is 175 DEG C, and the temperature of the fifth segment is 180 DEG C; the temperature of a die ranges from 40 DEG C to 80 DEG C; the inflation pressure ranges from 0.6 MPa to 0.8 MPa; the blowing time is 20 s; the cooling time is 40 s; the part taking time is 10 s; the molding period is 80 s; and the extrusion speed ranges from 100 cm<3>/s to 180 cm<3>/s. The technological process comprises the following steps that firstly, a started blow molding die is moved to the position below the extrusion machine head, a molded blank is extruded in the blow molding die, then die assembling is carried out, and the die is moved out of the position below the extrusion machine head; the mold blank is in contact with the die, a gas channel is formed in the center of the die, and compressed air is introduced in to the molded blank for blowing up the mold blank, so that the mold blank is in contact with the inner surface of the blow molding die, and after cooling shaping, the die is opened for part taking.

Description

technical field [0001] The invention relates to the technical field of hollow blow molding, in particular to a molding process in which inflation pressure controls the wall thickness distribution of hollow blow molding products. Background technique [0002] Extrusion blow molding is commonly used in the molding processing of bottles, barrels, pots, cans and other containers, and is widely used in food, daily necessities, chemical and pharmaceutical industries. With the continuous development of plastic modification technology, plastic materials are widely used in industrial parts. Many modified plastics have good blow molding performance. At present, extrusion blow molding has been widely used in the molding of large and medium-sized hollow industrial parts. Processing, such as automotive dashboards, plastic fuel tanks, household appliances, tool boxes, etc. [0003] The extrusion blow molding process is complex, and there are many factors that affect the uniform distribut...

AI Technical Summary

Problems solved by technology

With the increase of the inflation pressure, the deformation speed of the parison is accelerated, and the flat section parison, due to the relatively small inflation, rapidly deforms and sticks to the inner wall of the mold. Due to the sudden cooling of the mold, the deformation does not occur, but the inflation ratio is relatively large. The part of the parison needs to continue to deform until it sticks to the inner wall of the mold; because in the free inflation stage, the part with a larger inflation ratio corresponds to a larger deformation of the parison and a thinner wall thickness, so the minimum wall thickness of the final formed fuel tank part is smaller , the standard deviation of wall thickness distribution increases, and the uniformity of wall thickness distribution becomes worse