Stator Winding Weld Inspection Using 3D Bare-Area Analysis

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Solution Overview

Problem

Conventional quality control of welding joints between conducting elements of inductive windings in stators is time-consuming, costly, and prone to human errors, requiring subjective evaluation that lacks precision and reliability.

Innovation Solution

A method utilizing 3D reconstruction and computer-aided analysis to objectively assess welding joints by extracting 2D grayscale blobs, calculating center of mass, and analyzing profiles to identify bare zones and calculate bare areas with high precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional visual inspection by human operators is used to evaluate welding joints, then subjective assessment can be performed, but the process is time-consuming and prone to human errors

Engineering Contradiction:
Improvequality control reliabilityVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical visual inspection process performed by human operators with an automated optical measurement system. The system uses a camera to capture images of welding joints and processes them through computer algorithms to objectively evaluate weld quality, thereby eliminating human subjectivity and significantly reducing inspection time while improving reliability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a digital copy of the welding joint through image capture and processing. By generating a grayscale image and extracting profile data from the visual information, the system transforms physical weld characteristics into digital data that can be precisely measured and analyzed, enabling rapid and repeatable quality assessment

Inventive Principle:
Principle #26Copying

2Productivity

If automated optical measurement system is used to assess welding joints, then inspection speed and precision are improved, but the device complexity increases

Engineering Contradiction:
Improveinspection speedVSAvoidmeasurement system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the complex task of welding joint evaluation into distinct processing stages: image capture, grayscale conversion, profile extraction at specific heights, and automated classification. This segmentation allows each stage to be handled by specialized computational routines, improving processing efficiency while keeping the overall system manageable through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the physical welding joint into a digital representation through parameter changes. By converting the joint image to grayscale, extracting height profiles at specific positions, and representing the weld geometry as numerical data points, the system enables rapid computational analysis that significantly improves inspection speed despite the added complexity of data processing

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4476686B1Method for quality control of a welding joint between a pair of ends of conducting elements of an inductive winding of a stator
Publication Date: 2026.04.01 ATOP SPA
  • EP4476686B1 patent drawingFigure 1
  • EP4476686B1 patent drawingFigure 2~3
  • EP4476686B1 patent drawingFigure 4

AI summary

A method for quality control of a welding joint (16) between a pair of ends of conducting elements of an inductive winding of a stator, the method being performed by a computer (10) and comprising the steps that consist in: - acquiring (20) a 3D reconstruction (40) of the welding joint (16); - extracting (22) a white 2D grayscale blob area (42) from the 3D reconstruction (40) of the welding joint (16); - calculating a center of mass of the 2D grayscale blob area (42) in order to determine a rotation axis (46) orthogonal to the cutting plane (41) and passing through the center of mass; - extracting (24) a plurality of profiles (50) from the 3D reconstruction (40) of the welding joint (16), by longitudinally sectioning the 3D reconstruction (40) with a plurality of planes (44) that are orthogonal to the cutting plane (41), proceeding in rotation about the rotation axis (46), each orthogonal plane (44) comprising a respective profile (50) of the 3D reconstruction (40); - searching for and identifying (26) bare zones (62) of the welding joint (16) by analyzing one by one the profiles (50) of the 3D reconstruction (40), calculating for each profile portion (50) a respective straight interpolation line (54) on the points that constitute the profile portion (50), the latter being identified as a bare zone (62) if the respective straight interpolation line (54) has an angular coefficient (56) with an absolute value smaller than or equal to 10°; and - calculating (28) a bare area (18) of the welding joint (16) by summing the bare zones (62) identified by the analysis of the profiles (50) of the 3D reconstruction (40), the contribution of each bare zone (62) to the bare area (18) being equal to an arc of an annulus comprised between the respective profile (50) in which the bare zone (62) has been identified and the following profile (50) from the analysis of the profiles (50).