Spoiler Plastic Part Pin Network for Stronger Vibration Welds

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Solution Overview

Problem

The vibration welding process for manufacturing motor vehicle spoilers and door strips using polypropylene with mineral fillers can result in bumps and deformations, reduced tear resistance, and the deposition of dust or residues that cause painting defects due to the presence of mineral fillers, which complicates the manufacturing process.

Innovation Solution

A plastic part with a network of raised pins or studs configured to improve the welding process, featuring a specific distribution and geometry to enhance tear-off and peeling resistance, including a staggered pattern and uniform surface density, which forms a connecting interface upon welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vibration welding process is used to assemble spoiler parts, then manufacturing time is reduced and process complexity is lowered, but tear resistance of the assembly deteriorates due to filler content

Engineering Contradiction:
Improvemanufacturing timeVSAvoidtear resistance
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies local quality by creating a welding zone with concentrated raised pins (density 0.08-0.12 pins/mm²) in specific contact areas, rather than uniform distribution. This localized pin network focuses the welding action to generate sufficient heat and mechanical interlocking in critical zones, compensating for the overall reduced weldability caused by mineral fillers in the polypropylene material.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The welding interface is segmented into multiple discrete raised pins arranged in staggered patterns, rather than a continuous welding surface. This segmentation allows each pin to independently generate friction heat and create mechanical interlocking, with the collective effect of many small pins compensating for the poor weldability of filler-containing materials while maintaining production speed.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If vibration welding is performed on parts containing mineral fillers, then manufacturing process is simplified, but surface quality deteriorates due to dust and residue deposition

Engineering Contradiction:
Improveprocess complexityVSAvoidsurface quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent extracts the harmful mineral fillers from the welding contact zones by concentrating the welding action on raised pins that protrude from the filler-containing material. The pins create localized welding points that minimize the generation and deposition of dust and residues on the surrounding skin surface, while still achieving adequate bond strength through the pin network.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If raised pins are added to improve weld strength, then tear resistance improves, but device complexity increases due to additional structural features

Engineering Contradiction:
Improveweld strengthVSAvoidpart structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the structural reinforcement function with the welding function by integrating raised pins directly into the spoiler part structure. These pins serve dual purposes: they provide mechanical strength to the part itself and simultaneously create the welding interface for assembly. This eliminates the need for separate welding fixtures or additional fastening elements, reducing overall device complexity despite the added pin features.

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

The solution significantly improves the tear-off and peeling resistance of the assembled parts, reducing defects and enhancing the mechanical strength of the weld, while minimizing the appearance of residues that hinder painting.

Implementation Method 1

making them rub against each other in a joint plane by creating an alternating movement of one part on the other in the direction of the length of the part, while keeping them under pressure. In the contact zone(s), heating occurs which produces melting of the material

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

heating occurs which produces melting of the material when the temperature exceeds the melting temperature of the material(s) constituting the skin and/or the lining

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

making them rub against each other in a joint plane by creating an alternating movement of one part on the other in the direction of the length of the part

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3999323B1Plastic part used in the manufacture of a motor vehicle spoiler
Publication Date: 2025.06.25 NOVARES FRANCE
  • EP3999323B1 patent drawingFigure 1~2
  • EP3999323B1 patent drawingFigure 3~5
  • EP3999323B1 patent drawingFigure 6

AI summary

The invention relates to a plastic part (3) used in the manufacture of a motor vehicle spoiler (1) or motor vehicle door strip, the part (3) comprising at least one wall (32) intended to be vibration-welded to another component part (2) of the spoiler (1) or the door strip, characterised in that the wall (32) is provided with at least one network of raised pins (11, 21) intended to form a welding region (4, 5), the pins (11, 21) having a substantially identical shape, consisting of a cylindrical base and a conical end, the network comprising a plurality of rows (L1-L4) of pins (11, 21) extending in a first direction (D0), the pins (11, 21) of two adjacent lines being arranged in a staggered fashion, and in that the pins (11, 21) are distributed uniformly in the network, the surface density (ds') of the pins (11, 21) in the network being between 0.08 pins/mm2 and 0.12 pins/mm2, and preferably between 0.10 pins/mm2 and 0.11 pins/mm2.