Two-Material Injection Molding to Hide Vehicle Headlamp Injection Marks
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Solution Overview
Problem
Existing two-material injection molding methods for vehicle headlamps result in undesirable injection marks or residues due to material remnants in the runners, requiring costly and time-consuming separate steps to achieve homogeneous surfaces.
Innovation Solution
A method involving a first and second injection unit, along with specific tool parts, forms components with a first material and over-molds injection marks with a second material, ensuring the marks are hidden within the holder, using cold runners to allow weight flexibility and material choice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If material is injected into runners to form components, then components are produced, but injection marks or residues remain on the components
Solution Approach 1:
The patent converts the harmful injection marks into a beneficial feature by using them as registration elements for aligning multiple components during assembly. The marks that were previously defects are now functional features that facilitate precise positioning and assembly of the components.
2Manufacturing precision
If injection marks are removed to create homogeneous surfaces, then surface quality is improved, but additional processing steps are required
Solution Approach 1:
Instead of removing the injection marks through additional processing, the patent repurposes them as functional alignment features. This eliminates the need for separate removal steps while adding assembly functionality, thereby reducing overall process complexity.
3Manufacturing precision
If injection marks are removed to create homogeneous surfaces, then surface quality is improved, but production time and cost increase
Solution Approach 1:
The patent transforms the previously problematic injection marks into useful alignment features, eliminating the need for time-consuming removal operations. This conversion maintains surface quality acceptance while significantly improving production efficiency and reducing costs.
4Adaptability or versatility
If cold runners are used for first runners, then weight flexibility and material selection are improved, but injection marks are more prominent
Solution Approach 1:
The patent accepts the prominence of injection marks when using cold runners for material flexibility, but compensates by repurposing these marks as functional alignment features. This approach maintains the advantages of cold runners while transforming the visual defect into a functional benefit.
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 2A~2B
AI summary
A two-material injection molding method for forming a construction element (10) for a vehicle headlamp, wherein the method comprises the following steps in chronological order: a) providing a first injection unit configured to inject a first material, and a second injection unit configured to inject a second material, further a first tool part (310) and a second tool part (320) for building at least two components (100), and a third tool part (330) for building the holder (200); b) building the first injection molding tool (300a) by bringing together the first and second tool parts (310, 320), wherein the second tool part (320) comprises first runners (321); c) forming the at least two components (100); d) separating the first and second tool parts (310, 320) from each other, wherein the at least two components (100) remain in the first tool part (310), wherein each component (100) comprises at least one injection mark (110); e) building the second injection molding tool (300b) by bringing together the first and third tool parts (310, 330), wherein the third tool part (330) comprises at least one second runner (331); f) forming the holder (200), so that the injection marks (110) of the components (100) are over-molded with the second material; g) separating the first and third tool parts (310, 330) from each other and ejecting the built construction element (10).