Liquid Container Molding With Segmented Supply Rod Structure
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Solution Overview
Problem
Existing liquid-filled container manufacturing methods face challenges in reducing molding time, particularly for containers with small-diameter mouths, and there is a concern that reducing the diameter of the spare supply tube weakens the spare supply rod.
Innovation Solution
A method involving an air discharge step where liquid is supplied at a pressure that does not stretch the preform, followed by a liquid blow molding step using a spare supply rod to mold the preform into a container shape, with additional steps for forming a headspace and managing pressure within the container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the intra-nozzle channel is enlarged to reduce molding time, then the molding speed increases, but the spare supply rod becomes too thin and weak to maintain structural integrity
Solution Approach 1:
The invention divides the supply system into two separate components: a spare supply tube that provides structural support and a spare supply rod that performs the stretching function. This segmentation allows the tube to be sufficiently thick for strength while the rod can be optimized for its stretching purpose, resolving the contradiction between molding speed and structural integrity.
Solution Approach 2:
The spare supply tube acts as an intermediary element between the blow nozzle and the spare supply rod. It provides a robust channel for liquid supply and structural support, while the rod inside it performs the stretching function. This intermediary structure enables the system to achieve both high molding speed and adequate strength.
2Loss of time
If the spare supply tube diameter is reduced to enlarge the intra-nozzle channel, then the molding time decreases, but the spare supply rod strength is compromised
Solution Approach 1:
By separating the structural support function (spare supply tube) from the stretching function (spare supply rod), the invention allows the tube to maintain adequate diameter for strength while the rod diameter can be minimized to reduce molding time, thus resolving the time-strength trade-off.
Solution Approach 2:
The invention moves the structural support function to a different dimensional consideration by using a tubular structure around the rod. This allows the system to optimize the rod diameter for speed while the tube provides the necessary structural dimension, effectively decoupling the time-strength relationship.
3Productivity
If liquid is supplied at high pressure to reduce air discharge time, then the air discharge speed increases, but the preform may be stretched prematurely before molding
Solution Approach 1:
The invention dynamically adjusts the liquid supply pressure in two stages: first at high pressure to rapidly discharge air, then at reduced pressure during the molding phase to prevent premature stretching. This dynamic pressure control resolves the contradiction between air discharge speed and shape control precision.
Solution Approach 2:
The system performs preliminary air discharge at high pressure before the actual molding begins, then transitions to controlled pressure for the molding phase. This preliminary action allows rapid air removal while maintaining precision during the critical molding stage.
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 method reduces the time required to mold the container while preventing air entrapment and bubbling, ensuring stable and efficient formation of the container shape and headspace.
Implementation Method 1
supplying a liquid at a level of pressure that does not cause stretching of the preform to the inside of the preform
Implementation Method 2
supplying a pressurized liquid to the inside of the preform
Data Source
AI summary
A liquid-filled container manufacturing method including: the air discharge step of discharging air from an inside of a preform, by supplying a liquid at a level of pressure that does not cause stretching of the preform to the inside of the preform through an intra-tube channel formed between an inner peripheral surface of a spare supply tube extending through a blow nozzle and an outer peripheral surface of a spare supply rod provided radially inward thereof; and the liquid blow molding step of molding the preform into a container with a shape conforming to an inner surface of a mold, by stretching the preform downward using the spare supply rod and supplying a pressurized liquid to the inside of the preform through an intra-nozzle channel formed between an inner peripheral surface of the blow nozzle and the outer peripheral surface of the spare supply rod.