Eccentric Container Blow Molding Temperature Control
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Solution Overview
Problem
The stretch blow molding method for manufacturing off-center containers often results in insufficient strength at deformed portions and increased variation in thickness distribution due to inadequate holding of the preform's bottom portion by the mold, affecting the container's quality.
Innovation Solution
A method involving a blow molding apparatus with a temperature adjustment mold that heats the body portion and cools the protrusion portion of the preform, allowing for precise temperature control and accurate positioning of the preform during molding, which suppresses deviations in thickness distribution by ensuring the preform is not excessively deformed during the bending process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the preform is bent by pushing up the bottom portion with a stretching rod and gripping by an upper bottom mold, then a neck bent container can be manufactured, but the container becomes thin at the shoulder portion where the deformation amount is large and the strength becomes insufficient
Solution Approach 1:
The patent applies parameter changes by controlling the temperature distribution across different portions of the preform. The body portion is heated to a higher temperature to increase plasticity and reduce deformation resistance, while the bottom protrusion portion is cooled to maintain strength during bending. This temperature parameter optimization allows the material to deform more uniformly without excessive thinning at the shoulder portion, thereby maintaining adequate strength while achieving the desired neck bent shape.
2Shape
If the bottom portion of the preform is pushed up by a stretching rod and gripped by an upper bottom mold, then the preform can be bent at a predetermined angle, but the variation in thickness distribution and appearance increases when the bottom portion cannot be appropriately held
Solution Approach 1:
The patent implements local quality by applying different temperature treatments to different portions of the preform. The body portion is heated to enhance plasticity for easier bending, while the bottom protrusion portion is cooled to maintain rigidity and improve gripping. This localized temperature control ensures that each portion of the preform has the appropriate mechanical properties for its specific function during the bending process, resulting in more consistent thickness distribution and appearance quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the strength and aesthetic appearance of off-center containers by maintaining uniform thickness and reducing variations, thereby improving the overall quality of the manufactured containers.
Implementation Method 1
a blow molding apparatus (100) with a temperature adjustment mold that heats the body portion
Implementation Method 2
cools the protrusion portion of the preform
Data Source
Figure 1(A)~1(C)
Figure 2(A)~2(C)
Figure 3
AI summary
A method of manufacturing an off-center container includes: stretching a preform having a bottomed shape with a stretching rod, the preform is made of resin and heated; and blow-molding the off-center container, in which a central axis of a container neck portion is displaced from a central axis of a container body portion, by introducing a pressurized fluid into the preform disposed in a mold. The off-center container has a flat shape in which a dimension in a first direction in a container cross section is longer than a dimension in a second direction perpendicular to the first direction. In a circumferential cross section of the preform, a thickness of a first region corresponding to a surface extending in the first direction of the container is set to be thicker than a thickness of a second region corresponding to a surface extending in the second direction of the container.