Spiral Sheet Transition Control for Dimple-Free Tubular Forming
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Solution Overview
Problem
In spiral forming manufacturing processes, achieving precise transitions between sheets to meet manufacturing tolerances and efficiently use material in forming structures like wind turbine towers is challenging due to issues with dimples and errors in rolling and fit-up between adjacent sheets.
Innovation Solution
The method involves dimensioning a collection of planar sheets to form curved configurations, such as frusto-conical structures, by controlling their relative orientation and using a roll bender to curve the sheets without in-plane deformation, facilitating accurate alignment and welding along spiral seams to reduce errors and ensure dimensional tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sheets are continuously roll-formed into curved shapes, then productivity is improved, but manufacturing precision deteriorates due to dimples and errors in rolling and fit-up between adjacent sheets
Solution Approach 1:
The continuous sheet material is divided into discrete planar sheets that are individually dimensioned and then joined together. Each sheet is precisely cut to specific dimensions with defined edge configurations, allowing for accurate control of the final tubular structure geometry while maintaining continuous production capabilities.
Solution Approach 2:
The planar sheets are pre-dimensionalized and pre-positioned in an abutting relationship before the rolling process. The edges are configured in advance to ensure proper alignment and fit-up, preventing dimensional errors and dimples during the subsequent curving and rolling operations.
2Manufacturing precision
If sheets are joined in abutting relationship to form curved configurations, then manufacturing precision is improved, but device complexity increases due to precise dimensioning and alignment requirements
Solution Approach 1:
The planar sheets are designed with asymmetric edge configurations where specific edges (mating edges) are configured to complement each other in a predetermined abutting relationship. This asymmetric design simplifies the alignment process by providing unique fitting surfaces that naturally guide proper positioning without requiring complex adjustment mechanisms.
Solution Approach 2:
Only specific edges of the planar sheets are precisely dimensioned and configured for mating (mating edges and alignment edges), while other portions of the sheets can have more relaxed tolerances. This localized precision reduces overall manufacturing complexity by focusing dimensional control only where it is critical for the final curved configuration.
3Manufacturing precision
If roll bender is used to curve sheets without in-plane deformation, then manufacturing precision is improved, but use of energy increases due to controlled curving process
Solution Approach 1:
The roll bender applies curvature control only to the extent necessary to achieve the desired tubular shape without over-curving or excessive deformation. By controlling the curving action to match the precise dimensional requirements of the pre-dimensionalized sheets, energy is used efficiently without waste from excessive forming operations.
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 approach allows for the formation of tubular structures with improved dimensional accuracy and efficient material use by minimizing dimples and errors, ensuring that the final structure meets manufacturing tolerances and optimizes material usage.
Implementation Method 1
a sheet of steel is fed into a mill and continuously roll-formed into a desired shape
Implementation Method 2
curving the stock material into a curved configuration
Implementation Method 3
spiral welding the stock material to form a frusto-conical structure
Data Source
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AI summary
Spiral forming devices, systems, and methods can be used to join edges of a of a stock material, in a curved configuration, along one or more joints to form tubular structures, such as conical and/or cylindrical structures (e.g., frusto-conical structures). A planar form of the stock material can be formed from a plurality planar sheets coupled to one another in an abutting relationship. By controlling relative orientation and shapes of the plurality of planar sheets forming the stock material and/or by controlling a position of a roll bender used to curve the planar form of the stock material into the curved configuration, the curved configuration of the stock material can be controlled through transitions between sheets to facilitate rolling the sheets to a desired diameter with a reduced likelihood of dimples or other errors and to facilitate fit up between adjacent sheets in the curved configuration.