Blow Molded Container Base Orientation via Inverted Protrusion
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Solution Overview
Problem
Conventional blow molding techniques struggle to effectively form containers with deep protrusions, such as container bases and grips, due to insufficient material orientation, leading to reduced structural integrity, instability during hot filling, and increased material costs from excess amorphous plastic sections.
Innovation Solution
The method involves a base assembly with a push rod mechanism that allows the parison material to stretch and orient within a cavity instead of around a protrusion, reducing cooling-induced orientation issues and thick amorphous sections, and enables repositioning of the base to improve stability and reduce material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional blow molding is used to form deep protrusions, then the container can be manufactured, but the plastic material cannot properly orient around the protrusion leading to insufficient structural integrity
Solution Approach 1:
The patent inverts the traditional approach by forming the deep protrusion outward from the mold rather than having it inset into the mold. This reversal allows the plastic material to flow over and around the protrusion during blow molding, enabling proper material orientation and crystallinity formation while maintaining structural integrity at the base and grip regions.
2Stability of the object's composition
If the parison material stretches around a deep protrusion, then the container shape is formed, but cooling reduces the ability of the material to stretch and orient properly
Solution Approach 1:
The patent applies preliminary action by forming the protrusion outward from the mold before the blow molding process begins. This allows the hot, pliable parison material to encounter the protrusion during inflation and flow around it while still at a temperature that enables stretching and orientation, rather than encountering a cold inset protrusion that would impede material flow.
3Shape
If deep protrusions are formed using conventional methods, then container features like grips and bases are created, but thick amorphous plastic sections form increasing material costs
Solution Approach 1:
By inverting the protrusion orientation to extend outward from the mold rather than inset into it, the patent enables more efficient material distribution. The parison material flows smoothly over the outward-protruding features during blow molding, eliminating the formation of thick amorphous sections that occur when material must compress around inset protrusions, thereby reducing material usage and costs.
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 crystallinity and rigidity of the container base and grip regions, improving structural integrity and stability while minimizing material usage and costs, allowing the container to stand securely on a flat surface without design compromises.
Implementation Method 1
The blow molding apparatus inflates the parison by forcing gas into the parison which causes the parison to stretch and take the shape of the container mold
Implementation Method 2
As the plastic contacts the deep protrusion of the mold, the plastic must stretch and flow around the protrusion into a recess. However, the plastic material is less able to flow and stretch around the protrusion because of the contact friction with the mold surface
Implementation Method 3
Orientation of plastic molecules occurs as the plastic material stretches, and the greater the material stretch, the higher the orientation. As the orientation of the plastic molecules increases, the molecules straighten and may form a crystalline structure. Typically, the higher the crystallinity of the plastic, the greater the rigidity of the plastic
Data Source
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AI summary
A method for forming a container (500) includes receiving a parison (304); enclosing the parison with a mold (300) that includes a cavity (210), and inflating the parison in said mold to form a blow molded container with a moveable region (502) at said cavity. The method further includes repositioning the moveable region before filling the blow molded container.