Plastic Splice Housing With In-Mould EMC Film Bonding
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Solution Overview
Problem
Existing methods for providing electromagnetic shielding in plastic housings are labor-intensive, costly, and lack durability, especially when applied to complex three-dimensional shapes, and often require multiple steps and post-moulding applications.
Innovation Solution
Integrate an electrically conductive film during the injection moulding process, ensuring the film conforms to the mould's 3D contours, and optionally preform it to match the final product shape, using an in-mould-label with aluminum and specific thickness for optimal conductivity and structural integrity, and incorporate fixation means like teeth for a strong bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional post-moulding conductive coatings are applied to plastic housings, then electromagnetic shielding is achieved, but the process becomes labor-intensive and time-consuming
Solution Approach 1:
The patent combines the conductive coating application with the injection moulding process by integrating a conductive foil into the mould cavity. The foil is embedded in the mould and bonds with the plastic material during injection, eliminating the need for separate post-moulding coating steps and achieving both structural formation and EMI shielding simultaneously
Solution Approach 2:
The conductive foil is pre-positioned within the mould cavity before the injection moulding process begins. This preliminary placement ensures that the shielding layer is already in position to receive the plastic material, allowing the bonding to occur during the standard moulding cycle without requiring additional post-processing steps
2Reliability
If traditional conductive coatings are applied after moulding, then electromagnetic shielding is provided, but the bond strength and durability are insufficient
Solution Approach 1:
The patent merges the conductive layer integration with the injection moulding process itself. The plastic material bonds directly to the conductive foil during moulding under heat and pressure, creating a strong mechanical and chemical bond that is inherent to the structural formation process rather than a superficial post-application coating
Solution Approach 2:
The patent creates a composite structure where the plastic housing material and conductive foil are bonded together as an integrated unit. This composite approach combines the structural properties of plastic with the conductive properties of the foil, achieving both mechanical strength and electromagnetic shielding in a single durable component
3Reliability
If conductive material is applied to complex three-dimensional shapes, then electromagnetic shielding coverage is attempted, but uniform and complete coverage is difficult to achieve
Solution Approach 1:
The patent adapts the conductive shielding layer to complex three-dimensional contours by using a flexible conductive foil that can conform to curved and irregular surfaces. The foil is positioned within the mould cavity to match the desired three-dimensional shape, ensuring that the shielding layer follows the exact contours of the housing regardless of geometric complexity
Solution Approach 2:
The injection moulding process itself provides the uniform distribution and complete coverage by injecting plastic material that fills the entire mould cavity and bonds to the conductive foil. This ensures that every surface area, including complex three-dimensional contours, receives uniform coverage as the molten plastic flows to fill all cavities and bonds to the pre-positioned foil
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 results in robust, durable, and efficient electromagnetic shielding with reduced manufacturing time and costs, ensuring complete coverage and consistent performance, suitable for complex electronic devices and automotive components.
Implementation Method 1
injection moulding plastic into the mould so that the injected plastic bonds with the electrically conductive film
Data Source
Figure 1~2C)
Figure 3
AI summary
A method of providing an electrically conductive layer to a plastic housing, in particular a splice housing for electromagnetically shielded cable harnesses, comprises the steps of: a) providing an electrically conductive film and a mould; b) inserting the film in the mould; c) injection moulding plastic into the mould so that the injected plastic bonds with the electrically conductive film.