In blow molding processing, how is the design principle of the bottle's structure?

The blow-up ratio of the parison diameter to the small diameter of the bottle should not exceed 4:1, as shown. This rule also applies to bottles with handles on the cross-section. The lower the blow-up ratio, the more uniform and consistent the wall thickness will be. Using a high blow-up ratio to blow mold bottles with thick bases will increase the bottle weight, extend the cooling time, and result in products with almost no strength.

(2) All surfaces are curved, inclined, and conical. While curved, inclined, and conical surfaces can give a square-like appearance, it is advisable to avoid square shapes with sharp corners and flat surfaces. This is because the thin-walled areas have low strength, significant changes in wall thickness, and flat surfaces are thick and prone to deformation. Deformation in thick-walled areas is due to poor cooling and uneven shrinkage. The improved shape of the container bottom is shown, from which it can be seen that the flat surface also has almost no load-bearing strength on the upper cargo.

(3) An occurrence of trapped gas can be present at sharp corners. It is formed instantaneously by the compression between the mold surface and the plastic, which can make the plastic at the corner extremely thin and lead to a decrease in impact resistance.

(4) Always avoid abrupt changes in cross-section and shape.