Post-Blow Molding Container Reshaping via Internal Overpressure
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Solution Overview
Problem
The blow molding process, particularly the BFS process, limits the precision in producing containers with sharp edges or flat surfaces, making it difficult to achieve precise shaping and edge profiles, which is crucial for functional requirements such as easy content removal without ventilation.
Innovation Solution
A method and device that involve inserting filled and closed containers into a receiving device with heat-adaptive web walls, using overpressure inside the container to reshape the container walls, and stabilizing the shape through continuous heating in an autoclave, allowing for precise edge profiling and stabilization without damaging the contents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blow molding process is used to produce containers, then the production speed is fast and the process is simple, but the manufacturing precision of edges and surfaces is poor
Solution Approach 1:
The process is divided into two distinct stages: first, rapid container production via blow molding; second, precision shaping via heat treatment and overpressure. This segmentation allows each stage to optimize for its specific goal - speed in production, precision in shaping.
Solution Approach 2:
The container is pre-formed through blow molding with basic geometry, then subsequently refined through heat treatment and overpressure shaping. The preliminary forming enables rapid production while the follow-up process achieves precision edges and surfaces.
2Manufacturing precision
If heat treatment with overpressure is applied to reshape container walls, then the manufacturing precision of edges and surfaces is improved, but the risk of damaging filling material or causing leaks increases
Solution Approach 1:
The container material's physical properties are temporarily changed by heating to a specific temperature range, making it pliable for shaping. The overpressure parameter is carefully controlled to achieve the desired shape change without exceeding the material's structural limits or compromising the seal.
Solution Approach 2:
Instead of using mechanical force directly on the container walls for shaping, the invention uses internal overpressure generated by the filling material itself. This substitution of the shaping mechanism allows uniform, controlled deformation from the inside without external mechanical contact that could damage seals.
3Manufacturing precision
If the container is heated to achieve shaping, then the manufacturing precision is improved, but the time required for the process increases
Solution Approach 1:
The heat treatment process is applied in a controlled, periodic manner within the autoclave cycle, heating the containers to the required temperature, maintaining it for the necessary shaping duration, then cooling. This periodic thermal cycling achieves precise shaping while optimizing the time required.
Solution Approach 2:
By controlling the temperature parameter within an optimal range and maintaining it for a specific duration, the plastic material reaches the ideal state for shaping. The overpressure is applied during this specific time window to achieve the desired surface flatness and edge precision efficiently.
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
Enables precise reshaping and stabilization of container edges and surfaces, preventing leaks and maintaining the integrity of the filling material, while achieving sterilization and germ reduction, especially beneficial for medical containers.
Implementation Method 1
Continuous heating, preferably carried out in an autoclave, until a maximum temperature level is reached, simultaneously results in a continuous expansion of the filling material and a continuous increase in the vapor pressure of the filling material in question in the container.
Implementation Method 2
This also leads to a continuous increase in pressure in the gas space inside the container, above the filling material, which leads overall to a continuous increase in the internal pressure in the container.
Implementation Method 3
an initially rounded fold line course for a fold line of the container, which results from the previous container production according to the blow molding, filling and closing process, into a sharper edge by pressing with space-free application merges with the wall material of the web walls of the receiving device
Data Source
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AI summary
A method for further shaping and/or dimensionally stabilising already filled and closed containers (1), which are produced in particular using a blow-moulding, filling and closing process, has at least the following steps: - introducing the container (1) in question into a receiving device, the walls (29) of which define at least part of a contour on which the container (1) is heated during a heat treatment process and to which said container adapts in a shaping manner or against which said container bears in a dimensionally stabilising manner, owing to the excess pressure generated in this manner in the container interior; and - removing the container (1) in question from the receiving device after shaping and/or dimensional stabilisation are complete.