Vehicle Door Handle Two-Shot Molding Metallic Finish

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Solution Overview

Problem

Chrome plating of vehicle door handles is costly, environmentally hazardous, and prone to corrosion, rust, bubbling, peeling, and chipping, leading to a poor appearance and safety issues.

Innovation Solution

A two-shot injection molding process using a structural core made of engineering thermoplastic with glass fibers and an outer layer containing milled materials like aluminum micro-flakes to achieve a metallic surface finish, eliminating the need for chrome plating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If chrome plating is applied to injection molded door handles, then a metallic appearance is achieved, but manufacturing cost increases and environmental harm occurs

Engineering Contradiction:
Improvemetallic appearanceVSAvoidmanufacturing cost
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent uses a composite plastic material containing metal flakes (aluminum, copper, bronze, nickel, or stainless steel) dispersed within a thermoplastic matrix. This composite material provides both the metallic appearance and structural integrity in a single injection molding process, eliminating the need for separate chrome plating operations and reducing manufacturing costs while avoiding environmental harm from plating chemicals.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent achieves metallic appearance through the optical properties of embedded metal flakes that reflect and refract light. By selecting different metal types and controlling their orientation and distribution, the material exhibits varying metallic lusters and colors, providing aesthetic versatility without requiring multiple plating layers or post-processing steps.

Inventive Principle:
Principle #32Color changes

2Illumination intensity

If chrome plating is applied to injection molded door handles, then a metallic appearance is achieved, but the process becomes lengthy and complex

Engineering Contradiction:
Improvemetallic appearanceVSAvoidmanufacturing time
Core Design Contradiction:
Illumination intensityVSLoss of time

Solution Approach 1:

The patent combines the structural core formation and metallic surface finish creation into a single injection molding operation. The metal-flake-containing plastic material is injected directly into the mold, forming both the door handle structure and its metallic appearance simultaneously, thereby eliminating the sequential steps of core formation, plating preparation, chrome deposition, and finishing operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metallic appearance is built into the material itself before injection molding, rather than being applied afterward. The metal flakes are pre-dispersed throughout the plastic material, ensuring uniform metallic distribution and appearance is achieved during the molding process itself, eliminating subsequent plating time.

Inventive Principle:
Principle #10Preliminary action

3Illumination intensity

If chrome plating is applied to injection molded door handles, then a metallic appearance is achieved, but corrosion and rust susceptibility increases

Engineering Contradiction:
Improvemetallic appearanceVSAvoidcorrosion resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent uses a composite where corrosion-resistant thermoplastic material encapsulates metal flakes, creating a protective barrier that prevents moisture and oxygen from reaching the metal particles. This structure maintains the metallic appearance while eliminating the corrosion and rust problems associated with exposed metal surfaces in traditional chrome-plated handles.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent replaces the expensive, maintenance-prone chrome plating with a durable, corrosion-resistant plastic-composite material that does not require periodic replacement or repair. The integrated metal-flake material provides long-term reliability without the degradation issues of plated surfaces.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Illumination intensity

If chrome plating is applied to injection molded door handles, then a metallic appearance is achieved, but the surface becomes prone to bubbling, peeling, and chipping

Engineering Contradiction:
Improvemetallic appearanceVSAvoidsurface integrity
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent creates a homogeneous composite material where metal flakes are uniformly distributed and bonded within the thermoplastic matrix. This integrated structure eliminates the layered interfaces present in chrome-plated components, preventing bubbling, peeling, and chipping by ensuring the metallic appearance and structural material are unified at the molecular level.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent achieves uniform distribution of metal flakes throughout the plastic material through controlled mixing and injection molding parameters. This homogeneous distribution ensures consistent metallic appearance and structural integrity throughout the door handle, eliminating localized weak points where plating defects typically occur.

Inventive Principle:
Principle #33Homogeneity

5Illumination intensity

If chrome plating is applied to injection molded door handles, then a metallic appearance is achieved, but safety hazards from sharp edges increase

Engineering Contradiction:
Improvemetallic appearanceVSAvoidsafety hazards
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent embeds metal flakes within a continuous thermoplastic matrix, creating a composite material where the plastic encapsulates the metal particles. This structure eliminates exposed sharp edges and protruding metal surfaces, providing a smooth, safe-to-touch surface that maintains metallic appearance without the cutting hazards of chipped or peeling chrome plating.

Inventive Principle:
Principle #40Composite materials

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

The process produces a lighter, cheaper, stronger, and safer door handle with a uniform metallic surface finish that is less prone to defects, reducing manufacturing costs and environmental impact while enhancing aesthetics and safety.

Implementation Method 1

a two-shot injection molding process using a structural core made of engineering thermoplastic with glass fibers and an outer layer containing milled materials like aluminum micro-flakes

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

structural core made of engineering thermoplastic with glass fibers

Methodology Applied
Scientific EffectFiber reinforcement:

Implementation Method 3

outer layer containing milled materials like aluminum micro-flakes to achieve a metallic surface finish

Methodology Applied
Scientific EffectParticle reinforcement:

Data Source

PatentEP3303744B1Vehicle door handle apparatus and two-shot injection molding process for producing components with a metallic surface finish
Publication Date: 2019.04.17 FCA US LLC
  • EP3303744B1 patent drawingFigure 1~3
  • EP3303744B1 patent drawingFigure 4~5
  • EP3303744B1 patent drawingFigure 6

AI summary

A vehicle door handle apparatus is disclosed that generally includes a structural core and an outer layer. The structural core has an outer surface, a base portion, and a handle portion that extends from the base portion. The outer layer extends about and covers the outer surface of at least the handle portion of the structural core. The structural core is made of a first material that contains an engineering thermoplastic and glass fibers for reinforcement. The outer layer is made of a second material that contains the engineering thermoplastic and a milled material to give the outer layer a metallic surface finish. Non-limiting examples of the engineering thermoplastic are polyoxymethylene and polybutylene terephthalate. A method is also disclosed for producing an injection molded component having a metallic surface finish such as the disclosed vehicle door handle apparatus.