Plastic Automotive Assembly Using Mechanical Fastening and Structural Adhesive

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Solution Overview

Problem

The existing methods for manufacturing automobile parts made of plastic material require the use of two different glues and additional bonding surfaces, which are costly and may not ensure the durability of the assembly during the polymerization process.

Innovation Solution

A method involving a structural element and an appearance element with assembly means that allows mechanical assembly during the polymerization of a structural adhesive, eliminating the need for additional adhesives and bonding zones, and featuring snap-fastening or fastener mechanisms for secure and cost-effective attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two different glues (structural glue and pre-maintaining glue) are used to assemble appearance element and structural element, then the assembly durability is improved, but the manufacturing cost increases and process complexity increases

Engineering Contradiction:
Improveassembly durabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the pre-maintaining glue from the assembly process, keeping only the structural glue for the final bonding. The mechanical assembly means (clips, lugs, or other fastening features) serve as the temporary holding mechanism during polymerization, replacing the need for a separate pre-maintaining adhesive layer.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the temporary holding function and final bonding function into a single structural glue application. The mechanical assembly means provides both temporary stabilization during curing and serves as part of the final structural assembly, eliminating the need for separate adhesive layers.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If two different glues (structural glue and pre-maintaining glue) are used to assemble appearance element and structural element, then the assembly durability is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveassembly durabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention removes the pre-maintaining glue step from the manufacturing process, reducing material costs and simplifying the assembly procedure. Only structural glue is applied to the bonding areas, eliminating the need for additional adhesive materials and application steps.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical assembly means (such as clips or lugs) serve as a temporary, disposable holding mechanism during the polymerization process. These features are integral to the plastic parts themselves rather than separate adhesive components, reducing overall manufacturing complexity and cost.

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

3Stability of the object's composition

If pre-maintaining glue is used to temporarily assemble appearance element and structural element, then the assembly stability during polymerization is improved, but the process complexity and cost increase

Engineering Contradiction:
Improveassembly stability during polymerizationVSAvoidprocess complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention replaces the chemical bonding mechanism of pre-maintaining glue with a mechanical assembly system. Features such as clips, lugs, or interlocking geometries provide temporary stabilization during polymerization without requiring additional adhesive materials, simplifying the overall process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts the temporary stabilization function from the adhesive system and implements it through mechanical features integrated into the plastic parts. This eliminates the need for pre-maintaining glue while maintaining assembly stability during curing.

Inventive Principle:
Principle #2Taking out (Extraction)

4Strength

If additional bonding surfaces are prepared for structural glue application, then the bonding strength is improved, but the manufacturing cost and process complexity increase

Engineering Contradiction:
Improvebonding strengthVSAvoidprocess complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention combines the bonding function with the mechanical assembly function into a single integrated system. The structural glue is applied to bonding areas that are part of the mechanical assembly features (such as clip surfaces or lug faces), eliminating the need for separate bonding surfaces and reducing overall process complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 ensures reliable and rapid assembly of the appearance element with the structural element during polymerization, reducing costs and eliminating the need for additional adhesives and bonding surfaces, while allowing for easier design and production of the parts.

Implementation Method 1

polymerize the bead of structural adhesive

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3172119B1Method for manufacturing an assembly made of plastic
Publication Date: 2019.03.13 NOVARES FRANCE
  • EP3172119B1 patent drawingFigure 1~2
  • EP3172119B1 patent drawingFigure 3~4
  • EP3172119B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for manufacturing an automotive part made of plastic which includes a structural element (2) and a finishing element (3). The manufacturing method includes the following steps of: I. Providing a structural element (2) having assembly means and at least one adherence area (12); II. Providing a finishing element (3) having assembly means and at least one adherence area (15); III. Depositing a bead of structural adhesive (14) on at least one adherence area (12) of the structural element (2) and/or on at least one adherence area (15) of the finishing element (3); IV. Rigidly connecting the structural element (2) and the finishing element (3) by a mechanical assembly of the assembly means; V. Polymerising the bead of structural adhesive (14); and VI. Cutting out the assembly means.