Coil Winding Control for Metal Sheet Springback and Layer Gaps

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Solution Overview

Problem

Conventional coil manufacturing methods face challenges in achieving dimensional accuracy due to springback and widthwise displacement of metal sheets during winding, leading to gaps between layers and increased work burden for correction.

Innovation Solution

A coil manufacturing apparatus that includes an unrolling unit, a feeder, a bending unit, and a control unit to accurately bend and wind band-shaped metal sheets onto a polygonal former, ensuring no gaps between layers and improved dimensional accuracy through precise control of the bending process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If winding torque of the former is increased to improve dimensional accuracy, then the metal sheet adheres more closely to the former, but springback results in gaps between layers and widthwise displacement

Engineering Contradiction:
Improvedimensional accuracyVSAvoidspringback
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary bending to the metal sheet before winding, creating pre-curves that match the former's shape. This preliminary action compensates for springback that will occur during winding, allowing the metal sheet to adhere closely to the former without requiring excessive winding torque. The pre-formed curves ensure the metal sheet maintains the desired shape even after winding forces are applied and released.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If winding torque is increased to reduce gaps between layers, then dimensional accuracy improves, but widthwise displacement of the metal sheet occurs

Engineering Contradiction:
Improvedimensional accuracyVSAvoidwidthwise displacement
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The bending unit performs preliminary bending of the metal sheet to create pre-curves that match the former's peripheral shape before winding begins. This preliminary shaping ensures the metal sheet conforms to the former's geometry, preventing widthwise displacement during the winding process and eliminating the need for high winding torque that would cause displacement.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If conventional winding is performed without preliminary bending, then the process is simple, but gaps between layers and bulging parts result

Engineering Contradiction:
Improveprocess simplicityVSAvoidgaps between layers
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a bending unit that performs preliminary bending of the metal sheet before winding. This creates pre-curves that match the former's shape, ensuring the metal sheet adheres closely to the former during winding. The preliminary action prevents gaps between layers and bulging parts while maintaining a relatively simple manufacturing process.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If meandering correction is performed at uncoiled side to correct displacement, then dimensional accuracy improves, but work burden increases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidwork burden
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary bending at the uncoiled side before winding, creating pre-curves that prevent widthwise displacement during the winding process. By addressing potential displacement issues before winding begins, the need for corrective meandering operations after winding is eliminated, reducing overall work burden while maintaining dimensional accuracy.

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

The apparatus ensures high precision in coil manufacturing by preventing bulging and displacement, enhancing manufacturing efficiency and quality by maintaining close contact between metal sheets and formers, and improving heat dissipation and mechanical characteristics.

Implementation Method 1

a bending unit configured to carry out a bending process in which the metal sheet fed by the feeder is bent before the metal sheet is wound onto the former, the bending unit being configured to form a widthwise extending crease on the metal sheet

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

springback inevitably results in gaps between the layers depending upon the rigidity of the metal sheet

Methodology Applied
Scientific EffectElastic recovery: Elasticity

Data Source

PatentEP2919242B1Coil and fabrication device therefor, and coil fabrication method
Publication Date: 2019.04.24 TOSHIBA IND PROD & SERVICES CORP
  • EP2919242B1 patent drawingFigure 1
  • EP2919242B1 patent drawingFigure 2
  • EP2919242B1 patent drawingFigure 3

AI summary

A coil manufacturing apparatus includes a bending unit (15) configured to carry out a bending process in which a metal sheet (2) fed by a feeder (14) is bent before rewound onto a former (16) and a control unit (20) configured to control the bending process based on a feed amount of the metal sheet (2) by the feeder (14) so that a winding start of the metal sheet (2) is shaped according to an outer peripheral shape of the former (16) and thereafter, according to an outer peripheral shape of the metal 1 sheet (2) lap-wound onto the former (16).