Cold Rolling Profile Production with Pre-Bending and Thickness Reduction

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Solution Overview

Problem

Existing cold-rolling processes for producing profiles from one-piece rolling stock are inefficient in material usage and cost-effective, particularly for profiles with varying thickness, as they often result in internal stresses and warping due to friction and rigidity, and are limited in reducing the number of stations required in the rolling mill.

Innovation Solution

The process involves bending the starting material along the rolling direction and reshaping it in the width direction with regional thickness reduction, where the bend is formed prior to or during thickness reduction, allowing for a larger spread with the same number of stations and canceling auxiliary bends before forming the reduced-thickness profile, using laterally offset forming regions and counter-rollers for support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the starting material is reduced in thickness by single-stage rolling, then material is saved, but internal stresses and severe warping occur due to friction and rigidity

Engineering Contradiction:
Improvematerial usageVSAvoidwarping and internal stresses
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The thickness reduction process is divided into multiple rolling stages instead of single-stage rolling. Each stage reduces the thickness incrementally, allowing the material to gradually adapt to the deformation and reducing internal stresses and warping while still achieving overall material savings.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Bent sections are formed in advance before the thickness reduction process. These pre-formed bends serve as guiding features that control the material flow during subsequent rolling stages, preventing uncontrolled warping and internal stress accumulation while enabling effective thickness reduction.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the number of rolling mill stations is reduced, then productivity increases, but the ability to produce profiles with varying thickness is limited

Engineering Contradiction:
Improvenumber of stationsVSAvoidcross-sectional design flexibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

Multiple functions are combined into fewer rolling stations. The stations perform both bending operations (creating auxiliary bends) and thickness reduction operations in an integrated manner, eliminating the need for separate dedicated stations for each function and thereby reducing the total number of stations required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rolling process uses dynamically adjustable parameters including variable bend radii, adjustable reduction amounts at different locations, and flexible positioning of forming regions. This allows a reduced number of stations to achieve diverse cross-sectional designs by adapting the process parameters rather than requiring dedicated stations for each profile type.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If auxiliary bends are canceled before forming the reduced-thickness profile, then surface quality is maintained, but additional process steps are required

Engineering Contradiction:
Improvesurface qualityVSAvoidprocess steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The auxiliary bends are periodically formed and then periodically canceled in an alternating sequence during the rolling process. This periodic formation and cancellation allows the material to be temporarily shaped for structural integrity during rolling, then restored to the desired final profile shape, maintaining surface quality while managing process complexity through rhythmic operational cycles.

Inventive Principle:
Principle #19Periodic 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

This method reduces material usage, minimizes internal stresses, and allows for a more flexible cross-sectional design while maintaining surface quality, enabling the production of profiles with multiple reduced-thickness sections using fewer rolling mill stations.

Implementation Method 1

reshaping the starting material in the width direction of the starting material with a regional reduction in thickness of the starting material

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

due to the friction transverse to the roll and the rigidity of the flat rolling stock, the material reduction is only converted into a stretching in the longitudinal direction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2085163B1Cold rolling process for the production of a profile
Publication Date: 2013.10.02 HILTI AG
  • EP2085163B1 patent drawingFigure 1A~2
  • EP2085163B1 patent drawingFigure 3A~3D

AI summary

A cold rolling process for producing a profile from a single piece of rolled material as starting material (6) by means of forming areas (38) of rolls (36) that serve the forming process comprises the process steps: - bending the starting material (6) by applying at least one bent section (8) extending along the rolling direction, and - forming the starting material (6) in the width direction of the starting material (6) by reducing the thickness of the starting material (6) in certain areas.