Metal-Plastic Joint Cladding for Structural Bond Strength

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Solution Overview

Problem

Existing methods for joining metal and plastic materials do not achieve sufficient strength for structural components, particularly in motor-vehicle structures, and are costly and weight-intensive.

Innovation Solution

A method involving the application of a cladding of metal and/or plastic material using additive manufacturing technology, combined with surface roughening and adhesive application, to enhance the joint's mechanical properties, along with local heating and quenching to reduce material stress and improve bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional joining methods (laser heating with adhesive or uneven surface) are used, then the joint can be obtained with basic strength characteristics, but the strength is insufficient for structural components

Engineering Contradiction:
Improvejoint strengthVSAvoidsuitability for structural applications
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention uses a composite cladding structure consisting of a first cladding layer of first material and a second cladding layer of second material deposited on the first element. This multi-material composite approach enhances joint strength beyond what single-material conventional methods can achieve, making the joint suitable for structural applications.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The cladding is applied locally at the joint region rather than uniformly across the entire component. The first and second cladding layers are deposited specifically at the interface between elements to enhance bonding, while the rest of the component maintains its original properties. This localized enhancement provides high strength where needed without unnecessary weight or cost elsewhere.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional joining methods are used, then the process is relatively simple, but the cost is high and weight increase is significant

Engineering Contradiction:
Improveprocess simplicityVSAvoidjoint weight
Core Design Contradiction:
Ease of manufactureVSWeight of stationary object

Solution Approach 1:

The invention changes the material parameters by selecting specific materials for the first and second cladding layers that provide high strength-to-weight ratio. By controlling the composition and thickness of these layers, the joint achieves structural strength requirements while minimizing weight increase compared to conventional heavy-duty joining methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The cladding is applied locally only at the joint region rather than coating entire components. This localized application significantly reduces the total amount of additional material required, thereby minimizing weight increase while still providing the necessary strength enhancement at the critical bonding interface.

Inventive Principle:
Principle #3Local quality

3Reliability

If conventional joining methods are used, then basic joints can be obtained, but they cannot meet the requirements for structural components in motor-vehicle structures

Engineering Contradiction:
Improvestructural component suitabilityVSAvoidjoint strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention employs a composite cladding structure with first and second cladding layers of different materials deposited on the first element. This multi-material composite approach creates a gradient transition at the joint interface, improving stress distribution and bonding strength to meet structural component requirements for motor-vehicle applications.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention creates a curved or graded transition zone through the cladding layers at the joint interface, rather than a sharp discontinuity. This curved transition distributes stress more evenly across the joint, preventing stress concentration and improving the overall reliability for structural applications.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 method significantly enhances the mechanical strength of metal-plastic joints without significant weight increase, making it suitable for structural applications in motor-vehicle production with reduced costs.

Implementation Method 1

the heat being obtained for example with the aid of a laser beam

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

a simultaneous application of heat, the heat being obtained for example with the aid of a laser beam

Methodology Applied
Scientific EffectLaser melting: Laser

Implementation Method 3

applying a cladding of metal material and/or plastic material above said joint, by means of additive manufacturing technology

Methodology Applied
Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 4

a method in which an energy source is used, such as a laser or plasma beam, to selectively melt layers of powders or wires of the metal material or plastic material

Methodology Applied
Scientific EffectSelective melting: Selective Laser Sintering

Implementation Method 5

a step of local quenching obtained by feeding a cold fluid above the cladding layer, immediately after the application of the cladding

Methodology Applied
Scientific EffectQuenching: Heat Treatment

Implementation Method 6

the application of a layer of adhesive in the joint can be provided

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3650207B1Method for obtaining a joint between elements of different materials
Publication Date: 2021.09.29 CENTRO RICERCHE FIAT SCPA
  • EP3650207B1 patent drawingFigure 1~2
  • EP3650207B1 patent drawingFigure 3~4
  • EP3650207B1 patent drawingFigure 5~7

AI summary

A joint between at least one element of metal material (1) and at least one element of plastic material (2) is obtained by pressing these elements in contact against each other, with a simultaneous application of heat. The method further comprises the step of applying a cladding (C) of metal material and/or of plastic material above the joint by additive manufacturing technology.