Method for cleaning extruding machine and die head of multilayer co-extrusion film blowing equipment

Abstract

The invention discloses a method for cleaning an extruding machine and a die head of multilayer co-extrusion film blowing equipment. The method comprises the following steps of: after the last batch of formulated products are produced by extruding the last batch of formulated materials out of all extruding machines respectively, adding new materials into corresponding extruding machines respectively to start cleaning the machine until the new materials clean the last batch of materials out of the extruding machine and the die head completely; and in the machine cleaning process, making the extrusion speeds of all the extruding machines continuously fluctuated and changed up and down by using a central controller, wherein the maximum extrusion speed of all the extruding machines at the highest speed reaches 1.4 to 1.8 times the normal extrusion speed of the extruding machine, but the sum of the extrusion speeds of all the extruding machines is kept constant at all time points in the machine cleaning process. In the method, an oscillating extrusion mode is used for all the extruding machines, so that the time consumed in the machine cleaning process is short, and a small number of raw materials are consumed.

Description

technical field [0001] The invention belongs to the technical field of multi-layer co-extrusion blown film production technology, in particular to a method for cleaning the extruder and die head of multi-layer co-extrusion blown film equipment. Background technique [0002] In the production process of multi-layer co-extrusion blown film, multiple extruders are used to extrude different material melts, and the materials extruded by each extruder are collected at the die head and extruded together to form a circular film with multi-layer materials. A film bubble is formed, and the compressed gas is wrapped in the film bubble to form an inflation, and the film bubble is rolled after being inflated and cooled. For multi-layer co-extrusion blown film equipment, there are many different raw material formulas in the production process. When one formula is converted into another formula, due to the viscosity of the molten material, a conversion process is required. The last batch ...

AI Technical Summary

Problems solved by technology

However, due to the friction and stickiness between the melt and the flow channel wall during the flow of the melt in the extruder and the die, the flow velocity in the middle of the flow channel is high, while the flow velocity of the melt near the flow channel wall Slow, the new sticky material is basically equal to the freshly washed out material to form a dynamic balance, and sometimes even a layer of material sticks to the flow channel wall to form a false wall 1 (such as Figure 1, The longer the arrow in Figure 1, the faster the speed of the part), the existence of the "false wall" phenomenon makes it difficult to completely obtain the flow channel wall surface Effective flushing, so the cleaning speed is very slow, usually takes about five hours, and consumes a lot of raw materials

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