Blow Molded Container Necks With Undercuts Using Moving Inserts
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Solution Overview
Problem
Traditional blow molding technologies cannot create containers with recessed neck geometries that have undercuts, limiting the integration of closures with the container and leading to potential leaks and increased production costs due to the need for secondary operations like trimming and reaming.
Innovation Solution
A process using moving mold inserts to create and remove containers with recessed necks, allowing for the formation of complex geometries with undercuts by displacing inserts in phases to provide clearance for mold opening, eliminating the need for secondary operations and enabling a closure attachment mechanism on the outside of the container's neck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional blow molding technology is used to create containers with recessed neck geometries, then the container can be produced with integrated closure design, but the molding process becomes impossible due to undercuts trapping the mold material
Solution Approach 1:
The mold is divided into multiple independent segments or inserts that can move relative to each other. The blow pin tool includes a movable insert that can be displaced axially to clear the undercut region formed by the recessed neck geometry, allowing the mold to open without material becoming trapped
Solution Approach 2:
The mold inserts are designed to be movable rather than fixed. The blow pin insert can dynamically adjust its position during the molding cycle, moving into and out of the undercut region as needed, enabling complex geometries that would be impossible with static mold components
2Ease of manufacture
If a straight shoulder design is used instead of recessed geometry, then the mold can open with straight-pull motion without material trapping, but the integration of closure with container is limited
Solution Approach 1:
The mold is segmented into movable inserts that can independently displace, allowing the formation of complex recessed geometries with undercuts while maintaining ease of mold opening. The blow pin tool includes a movable insert that clears undercuts during ejection
3Shape
If closure attachment mechanism is used from the inside of the dispensing orifice, then different neck designs can be achieved, but leaking probability increases due to less controlled geometry inside the container
Solution Approach 1:
Instead of attaching the closure from the inside of the dispensing orifice, the closure attachment mechanism is inverted to attach from the outside of the container's neck. This allows the closure to engage with the calibrated external neck surface, providing tighter tolerances and more reliable leak prevention
4Manufacturing precision
If trimming and reaming operations are performed on the neck, then excess material can be removed, but production costs increase and available recess geometry is restricted
Solution Approach 1:
The neck is calibrated to the required precision during the initial blow molding process itself, rather than requiring subsequent trimming and reaming operations. The movable mold inserts enable direct formation of the precise neck geometry, eliminating the need for secondary operations and reducing production complexity
Data Source
AI summary
The present invention is directed to a process for the manufacture of a blow molded container comprising a physical geometry that creates more than one undercut and a means for removal of said container from a mold used to form said container.