Aseptic Preform Molding via Localized Cooling and Thermal Retention
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Solution Overview
Problem
The existing systems for producing blow-molded containers face challenges in maintaining a consistent temperature during the transition from compression-molding to blow-molding, leading to potential deformation and the need for costly sterilization machines to achieve aseptic levels, especially when directly coupling preform molding and blow molding processes.
Innovation Solution
A system that maintains preforms in a high-temperature state by optimizing the metal mold design and process parameters, allowing preforms to be molded with a minimum temperature of 60°C, reducing the need for external heating and enabling aseptic filling without a separate sterilizing machine, by ensuring the preforms are in a heated sterilizing state throughout the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the metal mold interior is cooled for an extended period to lower the mouth portion temperature, then deformation due to stress and compressed air is avoided, but the body and bottom portions become too cool for sufficient stretch molding
Solution Approach 1:
The patent applies local quality by differentiating the cooling treatment for different portions of the preform. The mouth portion receives extended cooling to prevent deformation, while the body and bottom portions maintain higher temperatures suitable for stretch molding. This is achieved through the metal mold design that allows selective temperature control across different regions of the preform during compression molding.
2Reliability
If the preform temperature is lowered to prevent mouth portion deformation, then sealing and molding stability improve, but a large amount of heat energy is consumed during subsequent heating
Solution Approach 1:
The patent applies preliminary action by performing the necessary cooling of the mouth portion during the compression molding process itself, rather than requiring subsequent cooling steps. The metal mold is designed to cool the preform to the appropriate temperature range (20-40°C for the mouth portion) before removal, establishing the correct thermal state in advance and eliminating the need for additional cooling equipment or energy-consuming temperature adjustments later.
3Reliability
If a container sterilizing machine is added to achieve high aseptic level, then filling asepsis is improved, but system complexity and cost increase
Solution Approach 1:
The patent applies self-service by enabling the preform and subsequent container to achieve sterilization through their own thermal history. The preform is removed from the metal mold in a heated sterilizing state (above 60°C throughout), and this temperature is maintained during conveyance and blow molding. The container emerges from blow molding still warm enough to provide aseptic conditions for filling, eliminating the need for separate sterilizing machines and reducing system complexity.
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 ensures that blow-molded containers are produced with a high aseptic level, reducing the need for costly sterilization equipment and maintaining a consistent temperature profile, thereby improving production efficiency and aseptic quality.
Implementation Method 1
the preforms after compression-molded are successively taken out from the metal mold for molding in a high-temperature state and are successively fed to the container-producing unit of the next step in the high-temperature state
Data Source
AI summary
[Problem] To realize a predetermined “aseptic level of the containers” without introducing a container sterilizing machine and to reduce the burden for adjusting the temperature of the preform.[Means for Solution] A metal mold for molding, wherein a space width (t2) of at least the body portion in the space width for forming a thickness of from the body portion to the bottom portion of the preform is set to lie in a range of 1.18 to 2.11 times as great as a space width (t1) for forming a thickness of an upper end portion of the mouth portion of the preform. At the time of the compression molding, the preform is taken out in the state of a high temperature from a compression-molding machine 31 and is fed to a bottle-producing unit C while maintaining the state of a high temperature. Further, the inner surfaces of a clean box I in which the units are placed and the outer surfaces of the units are sterilized, and the interior of the clean box I maintains a positive-pressure state with the filtered clean air. The bottle-producing unit C and a filling/sealing unit D are neighboring and directly coupled to each other in the same clean box, and are partitioned by a WBZ 54.