Forming Tool Thermal Expansion Compensation

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Solution Overview

Problem

Existing forming tools face inaccuracies in dimensional accuracy due to loose mounting of dies and punches, which complicates thermal expansion compensation and alignment, leading to potential misalignment and reduced reproducibility in sheet metal forming.

Innovation Solution

The implementation of additional bearings on the tool parts that securely fasten the die and punch without play in the bearing plane, ensuring precise and stable positioning through aligned bearing axes and thermal insulation, while eliminating the need for complex centering guides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the die and punch are mounted loosely via floating bearings to compensate for thermal expansion, then thermal contraction or expansion can be compensated, but inaccuracies in relative alignment occur and dimensional accuracy is jeopardized

Engineering Contradiction:
Improvethermal expansion compensationVSAvoiddimensional accuracy
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The mounting system is segmented into multiple independent bearings (at least two per tool part) distributed across the tool structure. This segmentation allows each bearing to independently accommodate thermal movement while the collective arrangement maintains overall alignment, resolving the contradiction between thermal compensation and positioning accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution moves from a single-point mounting approach to a multi-point distributed mounting approach across the bearing plane. By distributing bearings in multiple locations rather than relying on a single centering mechanism, the system compensates for thermal expansion in multiple dimensions simultaneously while maintaining alignment accuracy.

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

2Manufacturing precision

If a centering guide is provided between the die and punch to maintain alignment, then dimensional accuracy is ensured, but the construction becomes complex and the centering guide must absorb high mechanical forces

Engineering Contradiction:
Improvealignment accuracyVSAvoidconstruction complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The complex centering guide mechanism is extracted and replaced by the bearing arrangement itself. The bearings are positioned and dimensioned to inherently provide the centering function through their geometric arrangement and tolerance specifications, eliminating the need for a separate centering guide component and its associated complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bearings serve multiple functions simultaneously: they provide mechanical support for the die and punch, allow thermal expansion compensation through bearing play, and maintain alignment accuracy through their precise geometric arrangement. This multi-functionality eliminates the need for separate centering guides.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the bearing axes are aligned on a common straight line through the center of mass, then thermal expansion effects are coordinated and compensated, but the design requirements for the tool increase

Engineering Contradiction:
Improvethermal expansion insensitivityVSAvoiddesign requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bearing arrangement utilizes asymmetric positioning relative to the tool geometry, with bearing axes aligned on a common straight line passing through the center of mass. This asymmetric but strategically aligned configuration optimizes thermal compensation performance while maintaining reasonable design requirements.

Inventive Principle:
Principle #4Asymmetry

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 design creates a forming tool insensitive to thermal expansion, allowing for the reproducible production of semi-finished products with precise shape and reduced energy loss, enhancing both dimensional accuracy and energy efficiency.

Implementation Method 1

fastens the die to the upper tool part with bearing play in the bearing plane to compensate for its thermal contraction or expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the bearing axes of the bearings, which run normal to their bearing plane, lie on a common straight line when the forming tool is closed, the mutual alignment of die and punch can be maintained in a more robust manner with respect to thermal expansion/contraction

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP3078430B1Forming tool
Publication Date: 2018.03.14 VOESTALPINE METAL FORMING GMBH
  • EP3078430B1 patent drawingFigure 1
  • EP3078430B1 patent drawingFigure 2
  • EP3078430B1 patent drawingFigure 3

AI summary

A forming tool (1) for producing a semi-finished or finished product from a metal sheet (2) is provided, comprising a first tool part (3) having a tool upper part (5), a die (6) and at least one first floating bearing (7) which attaches the die (6) to the tool upper part (5) with bearing clearance (18) in bearing plane (33) to compensate for its thermal contraction or expansion, and a second tool part (4) having a tool lower part (9), a punch (8) and at least one second floating bearing (11) which attaches the punch (8) to the tool lower part (9) with bearing clearance (32) in bearing plane (34) to compensate for its thermal contraction or expansion, wherein the punch (8) and die (6) cooperate to form the metal sheet (2).In order to create a forming tool (1) that is resistant to thermal expansion/contraction, it is proposed that the two tool parts (3, 4) each have at least one further bearing (12, 13) that attach the die (6) and punch (8) without play to the upper tool part (5) or lower tool part (9) in the bearing plane (33, 34).