Thermoplastic Container Injection Molding Welding
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Solution Overview
Problem
The existing methods for manufacturing thermoplastic containers, such as those used in the automotive sector for liquids and gases, face challenges including numerous handling steps, limited design flexibility, warping issues, and unreliable mechanical strength and tightness of weld seams, particularly in the blow molding process.
Innovation Solution
A method involving an injection molding process where both the upper and lower shells are produced simultaneously in an injection mold with a stepped parting plane, allowing for a stable and efficient connection through a circumferential weld seam formed during the same process, ensuring high mechanical strength and tightness without intermediate handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two half-shells are individually manufactured and then welded together using a heating mirror process, then design freedom is improved, but the number of handling steps increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the production of upper and lower half-shells and the formation of weld seams into a single injection molding process. The injection mold includes first and second mold halves that can be rotated relative to each other, allowing both half-shells to be produced simultaneously and then joined in the same tool without intermediate handling steps.
Solution Approach 2:
The injection mold serves multiple functions: it produces both the upper and lower half-shells, positions them for alignment, and forms the weld seams all in one tool. The mold system is designed to perform sequential operations (producing half-shells, rotating, joining) without requiring separate dedicated tools for each step.
2Adaptability or versatility
If two half-shells are individually manufactured and welded together, then design freedom is improved, but mechanical strength and tightness of weld seams cannot be reliably guaranteed
Solution Approach 1:
The patent performs preliminary actions by producing both half-shells with precisely defined edge areas in the same injection mold, ensuring exact alignment and congruency. The mold geometry pre-establishes the positioning and orientation of both half-shells before the welding operation, eliminating alignment errors that would compromise weld quality.
Solution Approach 2:
The patent replaces the conventional heating mirror welding process with an injection molding-based welding system. Instead of using external heating equipment and manual or robotic welding operations, the weld seams are formed by injecting molding material between the half-shells in the same tool, providing more reliable and consistent results.
3Adaptability or versatility
If a heating mirror process is used to weld half-shells, then design freedom is improved, but warping problems occur and manufacturing time increases
Solution Approach 1:
The patent changes the fundamental parameters of the welding process by transitioning from thermal welding (heating mirror) to injection-based welding. The molding material is injected in a controlled manner between the half-shells, providing uniform pressure and temperature distribution that prevents warping, whereas the heating mirror process creates localized thermal gradients that cause distortion.
4Device complexity
If conventional injection molding with separate tools is used for half-shells and welding, then manufacturing steps are simplified, but positioning accuracy and connection quality deteriorate
Solution Approach 1:
The patent merges the production and joining operations into a single integrated injection mold system. The first and second mold halves are designed with precise geometric features that ensure accurate positioning of the half-shells relative to each other. The rotation mechanism maintains precise alignment throughout the process, eliminating positioning errors that would occur with separate tools.
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 significantly reduces handling steps, enhances design flexibility, and guarantees a strong and tight connection between the shells, improving the overall manufacturing efficiency and quality of the containers.
Implementation Method 1
at least one upper shell (2) and at least one lower shell (3) are produced in parallel in an injection molding process
Implementation Method 2
a hot plate is placed between the two half-shells so that the thermoplastic material in the edge area liquefies or at least softens
Implementation Method 3
Injecting injection molding material into a cavity between or adjacent to the edge areas to form a circumferential weld seam between the upper part and the lower part
Data Source
Figure 1a~1g
Figure 2
Figure 3a~3e
AI summary
A method for producing a substantially closed container (1) for guiding and/or storing gases and/or liquids from a thermoplastic material comprises the following steps: in an injection mold with a first mold (28) and a second mold (29), which together provide at least one cavity (34) for an upper shell (2) and at least one cavity (35) for a lower shell (3) to a first injection molding position, at least one upper shell (2) and at least one lower shell (3) are produced in parallel in an injection molding process; opening of the injection mold, wherein the at least one upper shell (2) remains in the first mold (28) and the at least one lower shell (3) remains in the second mold (29);Rotating at least one of the two forms (29) so that the concave inner surfaces of the shells (2, 3) face each other and closing the form to a second injection molding position so that the substantially congruent edge regions (7, 8) of the shells (2, 3) come into at least partially planar contact; injecting injection molding material into a cavity (49) between or adjacent to the edge regions (7, 8) forming a circumferential weld seam (11) between the upper part (2) and the lower part (3); opening the injection mold and removing the at least one container.