Bridge Tool Sliding Mandrel for Variable Hollow Profile Extrusion

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Solution Overview

Problem

Existing extrusion processes are limited to producing profiles with constant cross-sections, leading to oversizing and inability to withstand high precision and tight tolerance requirements due to mechanical and thermal stresses on mandrel support arms, which results in reduced durability and precision issues.

Innovation Solution

A bridge tool with a mandrel constructed in multiple parts and a movable inner displacement mandrel with different cross-sections, connected via short lever arms and guide elements, allowing axial movement to change the profile's inner diameter, minimizing vibrations and enabling precise production of profiles with varying cross-sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a long mandrel support arm is used to enable varying cross-sections, then profile geometry flexibility is improved, but manufacturing precision deteriorates due to vibrations

Engineering Contradiction:
Improveprofile geometry flexibilityVSAvoidprofile precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The mandrel is divided into a fixed mandrel and a movable inner sliding mandrel with different cross-sections. This segmentation allows the movable portion to be adjusted independently to create varying profile cross-sections without requiring a long support arm, thereby maintaining manufacturing precision while achieving geometry flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner sliding mandrel is made axially movable relative to the fixed mandrel, allowing dynamic adjustment of the mandrel configuration during extrusion. This enables varying profile cross-sections to be produced without increasing the overall mandrel length, thus avoiding vibration-induced precision loss.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a long mandrel support arm is used to enable varying cross-sections, then profile geometry flexibility is improved, but reliability deteriorates due to thermomechanical stresses

Engineering Contradiction:
Improveprofile geometry flexibilityVSAvoidmandrel durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

By segmenting the mandrel into fixed and movable portions, the structure avoids the need for long support arms that would be subjected to high thermomechanical stresses. The segmented design allows each component to be optimized for its specific function, improving overall reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The movable inner sliding mandrel acts as an intermediary element that enables varying profile cross-sections without requiring long support arms. This intermediary mechanism transfers the function of geometry variation away from the stress-bearing support structure, thereby improving reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If direct extrusion is used to produce hollow profiles, then tool cost is reduced, but manufacturing precision deteriorates due to thermomechanical stresses on mandrel support arms

Engineering Contradiction:
Improvetool costVSAvoidprofile precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The axially movable inner sliding mandrel enables direct extrusion to produce varying cross-sections without requiring complex chamber tools or long support arms. This dynamic configuration maintains the cost advantages of direct extrusion while achieving the precision needed for varying profile geometries.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3645183B1Bridge tool for producing extruded profiled elements of varying cross-section
Publication Date: 2024.04.03 TECH UNIV BERLIN
  • EP3645183B1 patent drawingFigure 1~2
  • EP3645183B1 patent drawingFigure 3~4

AI summary

The invention relates to a bridge tool for a device for directly extruding hollow profiled elements of variable wall thickness, comprising a die (6) and at least one mandrel element (5) having a first end facing the die opening and an opposite second end, the outer profile contour of a hollow profiled element being defined by the geometry of the die opening and the inner cross-section of a hollow profiled element being defined by the at least one mandrel element (5), characterized in that the at least one mandrel element (5) has at least one cut-out, in which an inner sliding mandrel is arranged, said inner sliding mandrel being mounted for movement in the axial direction, the inner sliding mandrel having different cross-sections in the first end region of the inner sliding mandrel facing the first end of the mandrel element.