Blow-Molded Part Flange Integration for Tolerance Compensation

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Solution Overview

Problem

Existing blow molding processes face issues with dimensional inaccuracies and excessive shrinkage of injection-molded plastic parts, leading to gaps and reduced wall thickness, especially for large functional elements, resulting in defective parts.

Innovation Solution

A method involving a holding device with a holder and a radially extending flange on the functional element, ensuring contact with the preform during blow molding, forming a strong material-bonded and/or form-fit connection to compensate for manufacturing tolerances and prevent excessive wall thickness reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If injection-molded functional elements are used in blow molding, then functional integration is improved, but dimensional accuracy deteriorates due to shrinkage

Engineering Contradiction:
Improvefunctional integrationVSAvoiddimensional accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the geometric parameters of the functional element by adding a flange structure that extends radially outward. This flange compensates for shrinkage deformations by providing an additional contact surface that maintains proper positioning and connection even when the main body of the functional element shrinks during cooling after injection molding.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If large functional elements are used, then functionality is improved, but wall thickness reduction becomes excessive

Engineering Contradiction:
ImprovefunctionalityVSAvoidwall thickness
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent adds a radial dimension to the connection interface by extending a flange outward from the functional element body. This radial extension distributes the connection load over a larger surface area, preventing excessive localized wall thickness reduction while maintaining the functionality of large functional elements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If functional elements with reduced tolerances are produced, then manufacturing cost decreases, but connection stability deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidconnection stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent incorporates a flange structure during the injection molding process that pre-establishes a stable connection interface. This preliminary geometric feature ensures that even with reduced tolerance requirements, the functional element will maintain stable connection to the preform, as the flange provides inherent mechanical interlocking and surface contact.

Inventive Principle:
Principle #10Preliminary action

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

Enables the production of cost-effective blow-molded parts with reduced tolerances and stable attachments of functional elements, allowing for complex shapes and improved connections between the functional element and the base body.

Implementation Method 1

the preform attaches to the flange of the functional element and forms a base body

Methodology Applied
Scientific EffectMaterial bonding: Welding

Implementation Method 2

the preform, which consists of a thermoplastic material, is heated to a temperature above its melting point, so that material bonds can be achieved

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4674593A1Method for producing a blow-moulded part, and blow-moulded part
Publication Date: 2026.01.07 TI AUTOMOTIVE TECHNOLOGY CENTER GMBH
  • EP4674593A1 patent drawingFigure 1
  • EP4674593A1 patent drawingFigure 2
  • EP4674593A1 patent drawingFigure 3

AI summary

Method for producing a blow-molded part (1), comprising the steps of: - inserting a preform (10) made of thermoplastic material into a blow mold (2), - inserting a functional element (3) into the blow mold (2), wherein the functional element (3) is held in the correct position in the blow mold (2) by a holding device (4), wherein the holding device (4) has a holder (5) which partially receives the functional element (3), wherein the holder (5) has a projection (6) which extends in the longitudinal direction, wherein the functional element (3) has a radially extending flange (7) on the side facing the preform (10), - closing the blow mold (2), - carrying out the blow molding process, wherein the preform (10) attaches to the flange (7) of the functional element (3) and forms a base body (8).