Two-Shot Molded Vehicle Grille for Pedestrian-Safe Image Depth
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Solution Overview
Problem
Existing vehicle front panel or grille decorative parts require substantial thickness increases to achieve desired depth of image, leading to increased rigidity and potential pedestrian injury during collisions.
Innovation Solution
A two-shot (2K) injection molding process using a transparent plastic material for the A-side portion and an opaque elastomeric material for the B-side portion, which maintains the desired decorative appearance without significantly increasing the rigidity of the decorative part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the thickness of the decorative part is substantially increased to achieve desired depth of image, then the decorative appearance is improved, but the rigidity of the decorative part increases causing potential pedestrian injury during collisions
Solution Approach 1:
The decorative part is divided into multiple layers with different material properties: a rigid outer layer (PC) providing structural integrity and a softer inner layer (TPE) providing pedestrian safety. This segmentation allows each layer to fulfill its specific function without compromising the other, resolving the contradiction between rigidity and safety.
Solution Approach 2:
The patent uses composite materials consisting of a polycarbonate (PC) layer combined with a thermoplastic elastomer (TPE) layer. The PC provides the necessary rigidity and structural strength, while the TPE provides flexibility and pedestrian safety. This composite structure resolves the contradiction by combining materials with complementary properties.
2Shape
If the thickness of the decorative part is substantially increased to achieve desired depth of image, then the decorative appearance is improved, but the material and part costs increase
Solution Approach 1:
The decorative part is segmented into functional layers with the rigid PC layer providing structural support and the softer TPE layer providing aesthetic depth and safety. This segmentation allows for optimized material usage where each material is used only where its specific properties are needed, reducing overall material costs compared to uniformly thick designs.
Solution Approach 2:
The patent changes the material parameters by using different materials (PC and TPE) with different mechanical properties in different regions of the decorative part. This allows achieving the desired depth of image with controlled thickness distribution, optimizing material usage and reducing costs.
3Ease of manufacture
If a single-material decorative part is used, then the manufacturing process is simple, but the pedestrian safety is compromised due to increased rigidity
Solution Approach 1:
The patent employs composite materials (PC and TPE) in a multi-layer structure where the PC layer provides structural integrity and the TPE layer provides pedestrian safety through its softer, more compliant properties. This composite approach maintains manufacturing feasibility while eliminating the harmful effect of excessive rigidity.
Solution Approach 2:
The decorative part is segmented into functional zones with different material compositions: the outer PC layer for structural support and the inner TPE layer for safety. This segmentation enables the part to meet both manufacturing requirements and safety standards simultaneously.
Data Source
AI summary
A method of multi-shot injection molding of a decorative part for a front-end of a vehicle includes performing a first injection molding shot of a transparent plastic material to form an A-side portion of the decorative part and performing a second injection molding shot of an opaque elastomeric material for form a B-side portion of the decorative part. A multi-shot injection molded decorative part for a front-end of a vehicle includes an A-side portion formed by performing a first injection molding shot of a transparent plastic material and a B-side portion formed by performing a second injection molding shot of an opaque elastomeric material.