Injection Blow Molding Tool with Spatially Separated Areas
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Solution Overview
Problem
Existing injection-blow molding technologies have complex and fault-prone structures, leading to increased cycle times and higher pressures required for blow molding due to cooling of pre-molded parts, which complicates sealing and requires heat-resistant sealing devices, making it difficult to implement with standard components.
Innovation Solution
A tool with spatially separated injection and blow molding areas, allowing for parallel processing and automated transfer of pre-molded parts, using a blowing unit with a stretching core for mechanical pre-stretching, reducing the need for high blow molding pressures and simplifying the tool design by maintaining the pre-molded part in a warm, deformable state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If injection molding and blow molding are performed at the same position sequentially, then the structure is integrated, but the cycle time increases and the structure becomes complicated and failure-prone
Solution Approach 1:
The mold is divided into two spatially separated areas: an injection area for forming pre-molded parts and a blow molding area for forming final containers. This segmentation allows parallel processing of different stages, reducing cycle time while simplifying each area's structure to use standard components
Solution Approach 2:
The invention transitions from sequential processing at one position to spatial parallel processing by distributing injection and blow molding operations to different locations within the same mold, enabling simultaneous operation without increasing structural complexity
2Device complexity
If the pre-molded part is transferred to a blow-molding position by rotating it 180°, then the process can be separated, but the pre-molded part cools down requiring higher blow molding pressures
Solution Approach 1:
The invention performs preliminary mechanical pre-stretching of the pre-molded part using a stretch core in the blow molding area before introducing the blowing medium. This pre-stretching action maintains the plastic material in a deformable state, eliminating the need for high blow molding pressures that would be required if the part had cooled down
Solution Approach 2:
The stretch core acts as an intermediary mechanical element that prepares the pre-molded part for blow molding by applying controlled mechanical deformation. This intermediary action reduces the energy (pressure) required from the blowing medium to achieve proper forming
3Manufacturing precision
If higher pressures are used for the blowing medium to form cooled pre-molded parts, then forming is achieved, but sealing requirements increase requiring heat-resistant sealing devices
Solution Approach 1:
The invention changes the physical state parameters of the plastic material by performing mechanical pre-stretching while the material is still warm and deformable. This parameter change maintains the material's flexibility, allowing forming at lower pressures and thereby reducing sealing requirements to standard components
4Stress or pressure
If mechanical pre-stretching is performed, then the blowing medium pressure can be reduced, but additional components are required
Solution Approach 1:
The stretch core serves multiple functions: it acts as a support structure during transfer, performs mechanical pre-stretching of the pre-molded part, and serves as a centering element during blow molding. This multi-functionality reduces the need for additional separate components, keeping the tool design simple while achieving low-pressure forming
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 reduces cycle times, simplifies the tool design, and lowers the pressure requirements for blow molding, enabling the use of standard components from injection and blow molding technologies, resulting in a more efficient and reliable production process.
Implementation Method 1
a stretching core (33) which is movably mounted relative to the holding device (15) for mechanically pre-stretching the pre-molded part (1)
Implementation Method 2
a blowing unit (30) for forming the injection-blown container (2) by introducing a blowing medium, in particular compressed air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A tool (3) of an injection molding machine for forming an injection blow molded container (2), comprising a. an injection area (4) for forming a preform (1) and b. a blowing area (5) spatially separated from the injection area (4) for forming the preform (1) to form the injection blow molded container (2), wherein the blowing area (5) has a blowing unit (4) for introducing a blowing medium, preferably compressed air, into a cavity of the preform (1), wherein the blowing area (5) has a holding device (15) for holding the preform (1) and wherein the blowing unit (30) has a movably mounted stretching core (33) relative to the holding device (15) for mechanically pre-stretching the preform (1).