Vehicle Trim Element Manufacturing with Integrated Back-Injection
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Solution Overview
Problem
Existing methods for manufacturing vehicle trim elements using thermoplastic fiber-plastic composites require additional operations like punching holes and result in protrusions or depressions due to injection nozzle effects, lacking efficient moldability and tensile properties.
Innovation Solution
A method involving blending wood fibers, polypropylene, and polyethylene terephthalate fibers, needling, hot calibration, and back-injection into a mold at controlled temperatures to create a trim element without pre-punching, enhancing moldability and tensile properties through fiber entanglement and matrix formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If injection molding is used to manufacture trim elements, then production efficiency is improved, but additional operations like punching holes are required and protrusions or depressions are generated
Solution Approach 1:
The patent combines multiple operations (punching holes, molding, and injection) into a single integrated molding process. The trim element is manufactured in one continuous operation without requiring separate punching steps, thereby reducing device complexity while maintaining high productivity.
Solution Approach 2:
The molding operation is performed preliminarily to create the trim element with pre-formed recesses and protrusions that accommodate injection points. This preliminary shaping eliminates the need for post-molding hole punching and prepares the structure for direct injection, reducing subsequent operations.
2Productivity
If injection molding is used to manufacture trim elements, then production efficiency is improved, but protrusions or depressions are generated by injection nozzle
Solution Approach 1:
The molding step creates preliminary recesses at the injection points that are specifically designed to accommodate the injection nozzle. These pre-formed recesses allow the injection to occur without creating unwanted protrusions or depressions on the final surface, thereby maintaining manufacturing precision while preserving production efficiency.
Solution Approach 2:
The patent applies different local qualities to different regions of the trim element. The injection points have specially designed recesses with specific geometries that differ from the rest of the surface, allowing the injection nozzle to integrate seamlessly without creating visible defects, thus maintaining overall surface quality.
3Stability of the object's composition
If traditional molding methods are used, then material properties are maintained, but moldability and tensile properties are insufficient
Solution Approach 1:
The patent utilizes temperature as a critical parameter to change the material's properties during processing. The thermoplastic fibers are heated to become more deformable during molding, improving moldability, then cooled to regain strength and stability in the final product, achieving both ease of manufacture and material stability.
Solution Approach 2:
The patent employs composite materials consisting of thermoplastic fibers embedded in a plastic matrix. This composite structure provides both the deformability needed for molding and the final mechanical strength required for the trim element, resolving the contradiction between moldability and material stability.
4Strength
If multiple operations are used to manufacture trim elements, then material properties are improved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent merges multiple operations (molding, hole creation, and injection preparation) into a single integrated process. The trim element is molded with pre-formed recesses that simultaneously serve as structural features and injection access points, achieving good mechanical properties without requiring separate subsequent operations, thus reducing manufacturing complexity and costs.
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 method eliminates the need for pre-punching, improves mechanical properties like bending strength and resistance to humidity, and simplifies the manufacturing process by using a single mold for shaping and back-injection, reducing costs and tool requirements.
Implementation Method 1
the thermoplastic fiber-plastic composite comprises a plastic matrix embedding a reinforcing fiber, which becomes more deformable when heated with increasing temperature
Implementation Method 2
the needling step allows entangling the fibres, adding moldability and tensile properties for subsequent moulding
Implementation Method 3
the calibration is done at a temperature above 160°C, preferably between 200°C and 220°C
Implementation Method 4
the mould being at a temperature strictly below 70°C during the shaping step
Data Source
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AI summary
The invention relates to a method for manufacturing a trim element of a vehicle comprising the steps of : - blending (100) of a mixture comprising wood fibres, polypropylene (PP) fibres and polyethylene terephthalate (PET) fibres; - needling (110) the mixture to obtain a mat; - hot calibration (120) of the mat; - shaping (130) of the calibrated mat into a trim part; and - back-injection (140) of additional elements on the trim part to form the trim element. The shaping and back-injection steps (130, 140) are performed in the same mould, the mould being at a temperature strictly below 70°C during the shaping step (130). The invention further relates to a corresponding trim element.