Hollow Preform Injection Molding with High-Pressure Fluid Deformation
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Solution Overview
Problem
Existing blow molding methods are inadequate for producing components that require significantly higher pressures due to the plastic material or component shape, as they rely solely on heating and compressed air for deformation of a prefabricated and dimensionally stable preform.
Innovation Solution
A method involving the injection of a liquid plastic molding compound into a prefabricated preform, followed by fluid injection to build up high pressure, allowing for targeted deformation and shaping of the preform into a component with enhanced dimensional stability, using a mold with a first and second plastic injector and fluid injection technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If traditional blow molding methods are used to deform a prefabricated and dimensionally stable preform, then the process is simple and uses low pressure (7-40 bar), but it cannot achieve the required deformation for components requiring significantly higher pressures due to material properties or component shape
Solution Approach 1:
The deformation process is divided into two distinct stages: first, the preform is heated to increase deformability; second, high-pressure fluid (100-500 bar) is introduced to achieve the required deformation. This segmentation allows each stage to be optimized independently, resolving the contradiction between achieving high pressure and maintaining process simplicity.
Solution Approach 2:
The patent changes the physical state and properties of the working medium from compressed air at low pressure to high-pressure fluid (gas or liquid) injected through nozzles. This parameter change enables the system to achieve the necessary deformation pressures (100-500 bar) while maintaining control over the deformation process through regulated fluid introduction.
2Stability of the object's composition
If the preform is designed with high dimensional stability and reinforcement structures, then the component achieves high structural integrity, but significantly higher pressures are required to deform the preform
Solution Approach 1:
The preform is pre-heated before deformation to increase its deformability and reduce its dimensional stability temporarily. This preliminary action allows the subsequently introduced high-pressure fluid (100-500 bar) to deform the preform more easily, resolving the contradiction between maintaining high dimensional stability in the final component and achieving the high pressures needed for deformation.
Solution Approach 2:
The patent utilizes the phase transition or physical state change of the preform material through heating. By heating the preform to an elevated temperature, the material becomes more pliable and easier to deform, allowing high-pressure fluid to reshape the dimensionally stable preform without requiring excessively high pressures that would damage the reinforcement structures.
3Manufacturing precision
If high pressure is applied to deform a dimensionally stable preform, then components with high dimensional stability and reinforcement structures can be produced, but traditional blow molding equipment cannot generate the necessary pressures
Solution Approach 1:
The patent introduces a high-pressure fluid (gas or liquid) as an intermediary medium to transmit force to the preform. This fluid mediator allows the deformation process to achieve the necessary pressures (100-500 bar) and precision without requiring the preform handling and positioning mechanisms to directly withstand these extreme pressures, thus resolving the contradiction between manufacturing precision and power generation capability.
Solution Approach 2:
The patent employs pneumatic or hydraulic systems to generate and control the high-pressure fluid needed for preform deformation. By using regulated fluid injection through nozzles at pressures of 100-500 bar, the system achieves the necessary power and precision for deforming dimensionally stable preforms with reinforcement structures, overcoming the limitations of traditional blow molding equipment.
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 the production of components with high dimensional stability, allowing for the incorporation of reinforcement structures and varying cross-sectional sizes, achieving deformation under pressures much higher than traditional blow molding, resulting in components with improved structural integrity.
Implementation Method 1
a liquid plastic molding compound is injected into the preform cavity... a pressure is built up inside the preform that is significantly higher than the pressures known from the known blow molding processes
Implementation Method 2
A first fluid is injected under pressure into the liquid plastic molding compound, with a cavity being formed in the plastic molding compound by displacement of the plastic molding compound of the first plastic
Implementation Method 3
A second fluid is injected under pressure into the cavity, displacing the first fluid from the cavity
Implementation Method 4
Under the action of the temperature and/or pressure exerted by the plastic molding compound and/or the first fluid and/or the second fluid on the preform, the preform merges into the component
Data Source
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AI summary
The invention relates to a method for producing a component from a prefabricated and dimensionally stable preform which is designed as a hollow body and has a preform cavity and at least one opening, having the following steps: inserting the preform (21) into the mold cavity (2) of a plastic injection molding machine mold tool (1) equipped with a first plastic injector, closing the mold tool (1), injecting a liquid plastic molding compound of a first plastic (26) by means of the first plastic injector and introducing the liquid plastic molding compound into the preform cavity (23), injecting a first pressurized fluid into the liquid plastic molding compound of the first plastic (26), a component cavity (28) being formed in the plastic molding compound by displacing the plastic molding compound, and converting the preform (21) into the component, wherein the preform (21) is molded in a controlled manner, and the outer contour of the component is formed.