Liquid Blow Molding Suck-Back Orientation for Headspace Control
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Solution Overview
Problem
In liquid blow molding, the introduction of air bubbles into the liquid supply channel during the suck-back process leads to unstable liquid filling and moldability issues due to the entrainment of air in the preform, affecting the headspace formation and pressure within the container.
Innovation Solution
The method involves a nozzle engagement step, molding step, suck-back step, and nozzle separation step, where the suck-back is performed with the container in an upside-down posture to minimize air bubble entrainment, followed by upright nozzle separation, ensuring precise headspace creation and stabilizing the liquid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If suck-back is performed after liquid blow molding to create headspace, then headspace is formed in the container, but air bubbles are taken into the supply channel making subsequent molding unstable
Solution Approach 1:
The patent inverts the conventional sequence by performing the suck-back operation before the blow molding process. The pump sucks back a predetermined amount of liquid from the supply channel before supplying pressurized liquid for molding. This ensures that the supply channel is free of air bubbles during the actual molding process, eliminating the instability caused by air bubble entrainment while still achieving the required headspace after molding.
Solution Approach 2:
The patent performs the suck-back operation as a preliminary action before the blow molding process. By removing excess liquid and air bubbles from the supply channel in advance, the system ensures stable and reliable liquid supply during molding. This preliminary preparation prevents the harmful effect of air bubbles from affecting the molding quality and consistency.
2Quantity of substance
If air is entrained in the liquid supplied into the preform, then liquid fill is achieved, but air bubbles are taken into the supply channel during suck-back affecting pressure stability
Solution Approach 1:
The patent inverts the sequence by performing suck-back before blow molding. This ensures that any air bubbles present in the supply channel are removed before the pressurized liquid supply begins, guaranteeing stable pressure conditions throughout the molding process while still achieving complete liquid fill of the container.
Solution Approach 2:
The patent performs the suck-back operation quickly and efficiently before transitioning to the molding process. By rapidly removing air bubbles and excess liquid from the supply channel, the system minimizes the time air bubbles can affect the process, ensuring stable pressure conditions are established before molding begins.
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 approach allows for precise molding of a liquid container with a predetermined headspace, stabilizing the liquid filling and pressure, thereby enhancing the moldability and consistency of the liquid blow molding process.
Implementation Method 1
supplying pressurized liquid from the pump into the preform
Implementation Method 2
suck back a predetermined amount of liquid from the container by operating the pump in the reverse direction
Data Source
AI summary
A liquid blow molding method of molding a liquid container containing a content liquid from a preform, includes a nozzle engagement step of engaging a blow nozzle with a mouth portion of the preform; a molding step of molding the preform into a container of a predetermined shape by supplying a pressurized liquid into the preform; a suck-back step of sucking back a predetermined amount of liquid from the inside of the container to a supply channel by operating a pump in a reverse direction with the container put in the upside-down posture while the blow nozzle is engaged with the mouth portion; and a nozzle separation step of separating the blow nozzle from the mouth portion with the container put in the upright posture.