Blow Molding Mold Factors and Defects
The influencing factors of blow molding
The molding parameters of each stage are analyzed from the blow molding process. Blow molding process can be divided into four stages:
(1) the parcel formation stage of the polymer in the extruder in the transport, melting, mixing, pumped into the formation of the parison stage;Blow Mold at this stage, the main factors affecting the distribution of wall thickness are:
① molecular weight distribution of materials, the average molecular weight;
② the temperature control system and the screw speed of the blow molding machine, wherein the temperature control system includes hopper temperature, cylinder zone 1, zone 2, zone 3, zone 4 temperature, flange temperature, and storage mold head 1, Zone 3, Zone 4 Temperature.
(2) parison cutting stage parison from the die lip and the core of the gap into the cutting stage. At this point, the mold from the mold expansion and parison vertical expansion of these two phenomena affect the parison molding. The main process parameters affecting the wall thickness distribution are the die diameter and wall thickness control system of the blow molding machine. The control system includes the axial wall thickness control system and the circumferential wall thickness control system to adjust the gap between the die lip and the mold core.
(3) pre-blowing stage of the parison In order to avoid contact with the inner surface of the parison, adhesion,Blow Mold improve the uniformity of the wall thickness of the product, preforming of the parison. In the preforming stage of the parison, jet from the parison below the parison to protect the parison, reducing its vertical extension. At this stage, the main process parameters affecting the wall thickness distribution are: pre-blowing pressure, pre-blowing time.
(4) parison high-pressure blowing stage high-pressure inflated parison, so close to the mold cavity, to achieve plastic molding stage. At this stage, the impact of product molding is the deformation of the parison by high pressure, parison and mold cavity contact deformation. The main process parameters affecting the wall thickness distribution are: the shrinkage of the material; blowing pressure, time; mold materials, structure, mold exhaust system and mold cooling system, such as cooling water distribution, cooling water inlet temperature. Although the factors affecting the quality of blow molding products are more, but when the production conditions, product requirements to determine, adjust the blow molding process parameters can effectively improve the quality of products. Optimized process parameters can improve production efficiency, reduce raw material consumption,Blow Mold and optimize the overall performance of the product.
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