80–100° Neck-to-Body Angle in Preforms for Blow Molding
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Solution Overview
Problem
Existing methods struggle to reduce the thickness of preforms for resin containers while maintaining shape and specifications, leading to production defects and difficulty in achieving weight reduction and appropriate temperature distribution during blow molding.
Innovation Solution
A preform design with an angle of 80° to 100° between the central axis of the neck and body portions, combined with a temperature adjustment process that includes stretching and cooling to optimize the preform for blow molding, using an apparatus with specific molds and molds for injection, temperature adjustment, and blow molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the preform is reduced for weight reduction, then the weight of the resin container decreases, but production defects occur during injection molding and blow molding
Solution Approach 1:
The preform is designed with non-uniform thickness distribution, where the thickness varies in different regions (container body vs. bottom vs. neck) to optimize both weight reduction and structural integrity. This local variation in thickness allows critical areas to maintain sufficient strength while minimizing overall material usage.
Solution Approach 2:
The injection molding process parameters and preform geometry are optimized in advance to ensure proper filling and cooling before blow molding. The preform design includes preliminary considerations for the subsequent blow molding process, ensuring that the thin-walled structure can be properly formed without defects.
2Weight of moving object
If the thickness of the preform is reduced, then weight reduction is achieved, but it becomes difficult to maintain required shape and specifications during blow molding
Solution Approach 1:
The invention optimizes multiple parameters including the preform neck angle (80°-100°), thickness distribution profile, and material properties to achieve the desired balance between weight reduction and shape consistency. These parameter changes enable the thin-walled preform to maintain its shape during the blow molding process.
Solution Approach 2:
The blow molding process uses dynamic control of inflation pressure and timing to accommodate the reduced preform thickness. The process adapts to the thinner material by adjusting the forming dynamics to prevent excessive thinning or deformation that would compromise shape consistency.
3Weight of moving object
If the preform thickness is reduced, then weight reduction is achieved, but temperature distribution becomes difficult to control during blow molding
Solution Approach 1:
The preform design incorporates local variations in thickness that also affect heat distribution during the process. Thicker regions retain heat differently than thinner regions, and this is accounted for in the heating and blow molding process to achieve uniform temperature distribution across the entire preform surface.
Solution Approach 2:
The preform undergoes preliminary heating and temperature uniformization before blow molding. This preliminary action ensures that the entire preform, including the thinner sections, reaches the optimal temperature range for blow molding, eliminating temperature gradients that would cause forming defects.
4Weight of moving object
If the preform thickness is reduced, then weight reduction is achieved, but production defects occur during injection molding and release from mold
Solution Approach 1:
The invention optimizes injection molding parameters including injection pressure, injection rate, and mold temperature to accommodate the reduced preform thickness. The neck angle of 80°-100° is specifically designed to facilitate easy release from the mold while maintaining structural integrity during the injection process.
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 solution achieves weight reduction and minimizes production defects by ensuring adequate resin volume and temperature control, allowing for efficient production of resin containers with reduced weight and improved shape consistency.
Implementation Method 1
forming the second preform by stretching the first preform and bringing the first preform into contact with an inner wall surface of a temperature adjustment cavity formed by a temperature adjustment mold
Implementation Method 2
forming the second preform by stretching the first preform
Data Source
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AI summary
A preform (20) for producing a resin container including a container head portion, a container body portion, and a container bottom portion includes an annular neck portion (21) that forms the container head portion, and a body portion (22) that forms the container body portion and the container bottom portion. An angle (θ) formed by a central axis (X) of the neck portion (21) and the body portion (22) ranges from 80° to 100°.