Plastic-to-Metal Optical Jointing via Microstructured Undercuts
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Solution Overview
Problem
Conventional methods for joining luminously efficacious plastic parts with metal components in vehicle lighting devices are complex, require additional components, and can lead to high local stresses and undesirable deformations under mechanical load, especially when maintaining narrow tolerances.
Innovation Solution
A method involving the generation of a microstructure with undercuts on the metal component's joining surface, where the plastic part's material is softened by heat and pressed into these undercuts to form a strong, gas- and liquid-tight connection without additional elements or substances, utilizing techniques like laser irradiation or IR heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional joining methods (screw connections, adhesive joints, clamping joints) are used to join plastic components to metal components, then the connection can be achieved, but the design becomes complex and requires multiple additional parts
Solution Approach 1:
The patent combines the joining function directly into the plastic component by integrating a joining element (such as a latching hook or forming element) into the plastic part itself, eliminating the need for separate screws, adhesives, or clamping elements. This merging of functions reduces device complexity while maintaining reliable joint connections between plastic and metal components.
Solution Approach 2:
The patent extracts the joining function from separate additional components and integrates it directly into the plastic component. By taking out the need for separate joining elements and embedding the joining capability within the plastic part, the design simplifies the overall structure while achieving reliable connections.
2Reliability
If single-point force-transferring connections (screw connections, riveted connections) are used, then the connection can be established, but high local stresses occur in the plastic or metal material under mechanical load
Solution Approach 1:
The patent segments the force transfer from a single-point concentration to a distributed pattern across multiple contact points or a larger connection area. By using joining elements with extended contact surfaces or multiple engagement points, the mechanical load is distributed across the plastic and metal components, reducing local stresses while maintaining connection stability.
3Manufacturing precision
If conventional joining methods are used, then the connection can be made, but subsequent adjustment work is necessary to maintain narrow tolerances
Solution Approach 1:
The patent incorporates preliminary action by designing joining elements with built-in tolerance compensation features during the molding process. The joining elements are pre-configured with geometric characteristics that automatically accommodate tolerance variations, eliminating the need for subsequent adjustment work while maintaining manufacturing precision.
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 enables a robust, load-tolerant, and stress-free joint that maintains precise tolerances without the need for additional components or substances, ensuring a wide-area connection that avoids single-point stress peaks, suitable for sensitive optical elements like lenses and light conductors.
Implementation Method 1
softening the plastic material of the plastic part in an area near the surface of the complementary joining surface by introducing heat
Implementation Method 2
utilizing techniques like laser irradiation or IR heating
Implementation Method 3
pressing the plastic part and the metal component together with a pressure force in such a way that a portion of the softened plastic material penetrates the undercuts of the microstructure
Implementation Method 4
cooling the plastic material of the plastic part, forming a new strength of the softened plastic material of the structural part
Data Source
AI summary
A method for manufacturing a joining connection between a luminously efficacious part and a metal component of a lighting device of a vehicle. A microstructure is generated in a joining surface of the metal component, the microstructure having undercuts with respect to the joining surface. The plastic material of the plastic part is softened in an area of the complementary joining surface near the surface with the aid of an introduction of heat. The plastic part and the metal component are pressed together with a pressure force in such a way that a portion of the softened plastic material penetrates the undercuts of the microstructure. The plastic material of the plastic part is cooled thereby forming a new strength of the softened plastic material of the plastic part.