Molding Apparatus for Packaging Opening Device with Inclined Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing molding apparatuses for injection molding opening devices on packaging material face challenges in minimizing unmolding time and reducing material abrasion during the process.
Innovation Solution
The introduction of a third molding unit with inclined surfaces to facilitate the formation of a pull-tab with a constant thickness and reduced drag, allowing for efficient unmolding and minimizing material removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the molding apparatus uses conventional unmolding methods, then the structure is simple, but the unmolding time is long and material abrasion occurs
Solution Approach 1:
The patent applies the dynamics principle by making the mold surfaces movable rather than fixed. The first and second mold surfaces can move relative to each other along the thickness direction of the packaging material, allowing the mold cavity to expand during unmolding. This dynamic expansion creates clearance between the molded opening device and mold surfaces, enabling rapid ejection without waiting for complete cooling, thus reducing both unmolding time and cooling time.
2Manufacturing precision
If the mold surfaces are parallel to the pull-tab, then the structure is simple, but the pull-tab thickness varies and material abrasion occurs
Solution Approach 1:
The patent applies the asymmetry principle by orienting the first and second mold surfaces at angles relative to the pull-tab rather than parallel to it. This asymmetric angular configuration ensures that the mold surfaces are not parallel to the pull-tab length direction, creating a tapered mold cavity that produces pull-tabs with uniform thickness. The angled surfaces prevent friction and abrasion during ejection while maintaining precise dimensional control of the pull-tab.
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 configuration reduces the cooling time of the molten plastic and minimizes material abrasion, enhancing the overall efficiency of the injection molding process while maintaining the integrity of the opening device.
Implementation Method 1
the molten plastic material is injected, by means of a molding apparatus, onto a sheet cover portion of the prelaminated hole
Implementation Method 2
The first and second mold surfaces are inclined with respect to the second direction, by respective inclination angles, so as to facilitate the unmolding of the molded piece
Data Source
AI summary
A molding apparatus that injection molds an opening device on a packaging material sheet includes first and second molding units to injection mold a wall portion of the opening device on the sheet; the first molding unit comprising first and second molding elements configured to cooperate in contact to delimit at least part of a mold cavity fillable with molten material for forming a pull-member of the opening device; the mold cavity being delimited at least by first and second surfaces defined by the first and second molding elements respectively; a third molding unit cooperable with the first and second molding elements to delimit the mold cavity, and defining a third surface, facing the first and second surfaces and delimiting, together with these latter, the mold cavity; the third surface is shaped to be equidistant from the first and second surfaces when the first and second molding elements cooperate.