L-Shaped Preform Structure for Resin Container Thickness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Molding defects such as thickness distribution defects occur in resin containers due to inappropriate preform shapes during the molding process.
Innovation Solution
A preform with a neck portion, body portion, and bottom portion is designed with a connecting portion and narrow body portion connected in an L-shape, along with an injection molding mold and temperature adjusting mold to control preform temperature, using a manufacturing apparatus that includes an injection molding section, temperature adjusting section, and blow molding section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the preform shape is designed with conventional straight connections, then the manufacturing process is simple, but molding defects such as thickness distribution defects occur in the resin container
Solution Approach 1:
The preform body portion is segmented into multiple sections: a neck portion, a connecting portion, and a narrow body portion. This segmentation allows each section to have optimized dimensions and shapes that control resin flow and thickness distribution during blow molding, preventing defects while maintaining manufacturability
Solution Approach 2:
The connecting portion is designed with an asymmetric L-shaped configuration rather than a simple straight connection. This asymmetric design creates specific flow patterns during injection molding that prevent thickness distribution defects, while the asymmetry is carefully controlled to remain within manufacturing capabilities
2Manufacturing precision
If the preform has uniform temperature distribution, then the molding process is simpler, but molding defects occur due to inadequate temperature control at specific regions
Solution Approach 1:
The temperature adjusting mold applies different thermal treatments to different regions of the preform. The heater specifically heats the connecting portion to maintain resin flowability, while the cooling section cools the bottom portion to control crystallization. This localized quality control ensures optimal molding conditions without requiring complex system-wide temperature control
Solution Approach 2:
The temperature adjusting mold performs preliminary thermal conditioning of the preform before blow molding. By pre-heating the connecting portion and pre-cooling the bottom portion, the system prepares the preform in advance with the optimal temperature distribution needed for defect-free molding, simplifying the overall process control
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
The design and temperature control reduce molding defects, ensuring optimal preform shape and stretch ratio, thereby minimizing defects in the resin container manufacturing process.
Implementation Method 1
a heater (121a) provided to cover at least the connecting portion (22a)
Implementation Method 2
a cooling section (121b) provided closer to a bottom portion (23) than to the heater (121a)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A preform (20) manufactured by an injection molding section (110) of a blow molding apparatus in a hot parison method and blow-molded into a resin container by a blow molding section (130) includes a neck portion (21) that forms an opening of the preform (20); a body portion (22) that is connected to the neck portion (21); and a bottom portion (23) that is connected to the body portion (22) and closes one end of the preform (20). The body portion (22) includes a connecting portion (22a) connected to the neck portion (21) and a narrow body portion (22b) formed with a smaller diameter than the neck portion (21). The neck portion (21) and the connecting portion (22a), and the connecting portion (22a) and the narrow body portion (22b) are connected in an L-shape and form a step portion (22c).