Molded Article Rib Reinforcement Opening Deformation
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Solution Overview
Problem
In blow molding, the formation of openings in molded articles often results in deformation due to residual stress, leading to poor joining with other members as the balance of stress is broken when the closure portion is cut off.
Innovation Solution
A molded article with a rib disposed adjacent to the opening portion to reinforce the peripheral edge, and a method involving warping the side wall of the tubular portion before cutting off the closure portion to counteract residual stress and restore the shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the closure portion is cut off to form an opening portion, then the opening is created, but the balance of residual stress is broken causing deformation of the opening portion
Solution Approach 1:
A rib structure is formed in advance during the molding process at the position where the opening portion will be created. This preliminary structural reinforcement prevents deformation when the closure portion is subsequently removed, solving the problem of opening portion deformation without requiring complex post-processing steps.
Solution Approach 2:
The rib structure provides localized reinforcement specifically at the opening portion area, concentrating structural strength where needed. This allows the rest of the molded article to maintain its original properties while the opening portion gains enhanced resistance to deformation stress.
2Manufacturing precision
If the closure portion is cut off, then the opening portion is formed, but the opening portion may be deformed in a narrowed manner or the cut end may deform perpendicular to the opening surface
Solution Approach 1:
The rib structure is pre-formed during molding to provide structural support at the opening portion. This preliminary reinforcement ensures that when the closure portion is removed, the opening portion maintains its intended shape and dimensions, preventing both narrowing deformation and perpendicular deformation of the cut end, thereby ensuring reliable joining surfaces.
3Manufacturing precision
If a rib is disposed adjacent to the opening portion, then deformation of the opening portion is suppressed, but the device complexity increases
Solution Approach 1:
The rib structure introduces complexity only locally at the opening portion area rather than throughout the entire molded article. This localized approach provides the necessary deformation suppression while minimizing overall structural complexity and maintaining simplicity in other regions of the article.
Solution Approach 2:
The rib structure is integrated into the molded article during the same molding process, merging the reinforcement feature with the base structure. This combining approach avoids the need for separate components or post-assembly steps, thereby reducing overall device complexity despite adding local structural features.
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 rib suppresses deformation of the opening portion, ensuring accurate and stable joining with other components by balancing residual stress and restoring forces.
Implementation Method 1
In general, residual stress is present in the tubular portion constituting the disposal bag, and the balance of the residual stress is maintained in a state in which the closure portion is provided
Implementation Method 2
the side wall of the tubular portion, in a plane, is warped by an external force... a restoring force in the in-plane direction is generated on the side wall of the tubular portion
Data Source
AI summary
The purpose of the present invention is to provide a molded article and a manufacturing method for a molded article by which it is possible to mitigate deformation of an opening. The present invention provides a molded article comprising a cylindrical base and an opening provided in the base, wherein a rib is provided adjacent to the opening. The present invention provides a manufacturing method for a molded article that includes a molded body formation step for forming a molded body having a cylindrical portion provided at one end thereof with an occlusion by molding a melted resin, and a cut-off step for cutting off the occlusion by cutting the cylindrical portion, wherein in the cut-off step, the cutting is performed in a state where a side wall of the cylindrical portion is warped in-plane by an external force.