Preform Temperature Adjustment Mold for Axial Cooling and Shrinkage Control
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Solution Overview
Problem
Conventional temperature adjustment rod molds for preforms in hot parison blow molding fail to effectively adjust temperature differences in the axial direction, leading to difficulties in improving thickness distribution and controlling shrinkage and deformation of resin containers.
Innovation Solution
A temperature adjustment mold with a rod portion and annular projection that contacts the preform's inner surface, allowing for localized temperature adjustment and shrinkage control in the axial and radial directions, using a temperature adjustment rod with a projection portion to conduct heat and restrict shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional temperature adjustment rod mold is used that contacts the inner peripheral surface of the preform, then the preform temperature can be adjusted, but it is impossible to impart temperature difference in the axial direction
Solution Approach 1:
The temperature adjustment rod is segmented into multiple heating sections along the axial direction, each independently controllable. This allows different temperature conditions to be applied to different axial positions of the preform, resolving the contradiction between temperature adjustment capability and adaptability for localized temperature control.
Solution Approach 2:
The rod structure incorporates local heating zones with different thermal properties at different axial positions. By varying the heating capacity or thermal conductivity at specific locations, the system can impart localized temperature differences to specific regions of the preform, enabling both overall temperature adjustment and localized temperature control.
2Temperature
If the rod mold is in close contact with the inner peripheral surface of the preform, then heat conduction is efficient, but shrinkage and deformation of the preform cannot be restricted
Solution Approach 1:
The rod is divided into multiple functional sections: heating sections that contact the preform for heat conduction, and restriction sections (with larger diameter or protrusions) that contact the preform to restrict shrinkage and deformation. This segmentation allows simultaneous achievement of efficient heat transfer and shape control.
Solution Approach 2:
The temperature adjustment rod is designed as a multi-functional component that simultaneously performs heat conduction and shrinkage restriction. By integrating both heating zones and restriction zones into a single rod structure, the system achieves both temperature adjustment and shape control without requiring separate components.
3Manufacturing precision
If localized cooling is applied to improve thickness distribution, then the thin portion can be cooled from inside, but shrinkage and deformation of the preform occur
Solution Approach 1:
The rod incorporates localized cooling sections positioned at specific axial locations corresponding to thin portions of the preform. These cooling sections are integrated with restriction sections that prevent shrinkage and deformation, allowing localized temperature control for thickness uniformity without compromising preform shape.
Solution Approach 2:
The rod structure varies its thermal properties and mechanical constraints at different axial positions. Cooling sections with restricted shrinkage capability are placed at locations requiring thickness control, while maintaining overall preform shape. This local differentiation enables precise thickness distribution control without inducing unwanted shrinkage or deformation.
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 enables precise temperature distribution and reduced shrinkage, enhancing the thickness distribution and aesthetic quality of resin containers by locally cooling specific parts of the preform.
Implementation Method 1
The projection portion restricts shrinkage in a radial direction of the preform, conducts heat between the rod portion and the preform, and adjusts a temperature at a predetermined part in an axial direction of the preform
Data Source
AI summary
A temperature adjustment mold capable of performing local temperature adjustment in an axial direction from the inside of a preform while restricting shrinkage and deformation of the preform, for adjusting a temperature of an injection-molded bottomed resin-made preform includes a rod portion inserted into the preform and extending in the axial direction of the preform. The rod portion includes an annular projection portion that protrudes in a radial direction of the rod portion and contacts an inner peripheral surface of the preform. The rod portion contacts a bottom portion of the preform to restrict shrinkage in the axial direction of the preform. The projection portion restricts shrinkage in a radial direction of the preform, conducts heat between the rod portion and the preform, and adjusts a temperature at a predetermined part in an axial direction of the preform.