An On-Line ANN-Based Approach for Quality Estimation in Resistance Spot Welding

2010 ◽  
Vol 112 ◽  
pp. 141-148 ◽  
Author(s):  
Abderrazak El Ouafi ◽  
Rudy Bélanger ◽  
Jean-François Méthot
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Parameters ◽  
Dynamic Resistance ◽  
Resistance Curve ◽  
Weld Quality ◽  
Estimation Model ◽  
Quality Estimation ◽  
Resistance Spot ◽  
On Line

The aim of this study is to develop an effective on-line ANN-based approach for quality estimation in resistance spot welding. The proposed approach examines the welding parameters and conditions known to have an influence on weld quality, and builds a quality estimation model step by step. The modeling procedure begins by establishing relationships between welding parameters (welding time, welding current, electrode force and sheet metal thickness), welding conditions represented by typical characteristics of the dynamic resistance curve and welding quality indices (nugget diameter, nugget penetration, and indentation depth), and the sensitivity of these elements to the variation of the process conditions. Using these results and various statistical tools, three estimation models are developed. The first one is based exclusively on welding parameters. The second model is based on characteristics of the dynamic resistance curve. The third estimation model combines welding parameters and characteristics of dynamic resistance curves. In order to carry out the models building procedure, an extensive number of welding experiments are required. For this purpose, Taguchi’s efficient method of experimental planning is adopted. The results demonstrate that the developed models can provide an accurate on-line estimate of the weld quality, under different welding conditions.

Dynamic Resistance Based Model for On-Line Resistance Spot Welding Quality Assessment

2012 ◽  
Vol 706-709 ◽  
pp. 2925-2930 ◽  
Author(s):  
Abderrazak El Ouafi ◽  
R. Belanger ◽  
Michel Guillot
Keyword(s):  
Quality Assessment ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Assessment Model ◽  
Welding Parameters ◽  
Dynamic Resistance ◽  
Weld Quality ◽  
Quality Estimation ◽  
Resistance Spot ◽  
On Line

On-line quality assessment becomes one of the most critical requirements for improving the efficiency of automatic resistance spot welding (RSW) processes. Accurate and efficient model to perform non-destructive quality estimation is an essential part of the assessment. Besides the usual welding parameters, various measured variables have been considered for quality estimation in RSW. Among these variables, dynamic resistance (DR) gives a relative clear picture of the welding nugget formation and presents a significant correlation with the RSW quality indicators (QI). This paper presents a structured approach developed to design an effective DR-based model for on-line quality assessment in RSW. The proposed approach examines welding parameters and conditions known to have an influence on weld quality, and builds a quality assessment model step by step. The modeling procedure begins by examining, through a structured experimental design, the relationships between welding parameters, typical characteristics of the RD curves and multiple welding QI. Using these results and various statistical tools, different integrated quality assessment models combining an assortment of DR attributes are developed and evaluated. The results demonstrate that the proposed approach can lead to a general model able to accurately and reliably provide an appropriate assessment of the weld quality under variable welding conditions.

A Comprehensive Approach for Resistance Spot Welding Quality Estimation Using Dynamic Resistance Based Model

2012 ◽  
Vol 249-250 ◽  
pp. 732-738
Author(s):  
A. El Ouafi ◽  
R. Belanger ◽  
M. Guillot
Keyword(s):  
Quality Indicators ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Parameters ◽  
Dynamic Resistance ◽  
Weld Quality ◽  
Welding Quality ◽  
Quality Estimation ◽  
Resistance Spot ◽  
On Line

On-line quality assessment becomes one of the most critical requirements for improving the efficiency of automatic resistance spot welding (RSW) processes. Accurate and efficient model to perform non-destructive quality estimation is an essential part of the assessment. Besides the usual welding parameters, various measured variables have been considered for quality estimation in RSW. Among these variables, dynamic resistance gives a relative clear picture of the welding nugget formation and presents a significant correlation withseveral RSW quality indicators. This paper presents a structuredand comprehensiveapproach developed to design an effective dynamic resistancebased model for on-line quality estimation in RSW. The proposed approach examines welding parameters and conditions known to have an influence on weld quality, and builds a quality estimation model step by step. The modeling procedure begins by examining, through a structured experimental design, the relationships between welding parameters, typical characteristics of the dynamic resistance curves and multiple welding quality indicators. Using these results and various statistical tools, different integrated quality estimation models combining an assortment of dynamic resistance attributes are developed and evaluated. The results demonstrate that the proposed approach can lead to a consistentmodel able to accurately and reliably provide an appropriate estimationof the weld quality under variable welding conditions.

Modeling Dynamic Electrical Resistance During Resistance Spot Welding

2000 ◽  
Vol 123 (3) ◽  
pp. 576-585 ◽  
Author(s):  
S. C. Wang ◽  
P. S. Wei
Keyword(s):  
Electrical Resistance ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Transport Processes ◽  
Dynamic Resistance ◽  
Resistance Curve ◽  
Bulk Resistance ◽  
Resistance Spot ◽  
Faying Surface ◽  
Stage 4

Dynamic electrical resistance during resistance spot welding has been quantitatively modeled and analyzed in this work. A determination of dynamic resistance is necessary for predicting the transport processes and monitoring the weld quality during resistance spot welding. In this study, dynamic resistance is obtained by taking the sum of temperature-dependent bulk resistance of the workpieces and contact resistances at the faying surface and electrode-workpiece interface within an effective area corresponding to the electrode tip where welding current primarily flows. A contact resistance is composed of constriction and film resistances, which are functions of hardness, temperature, electrode force, and surface conditions. The temperature is determined from the previous study in predicting unsteady, axisymmetric mass, momentum, heat, species transport, and magnetic field intensity with a mushy-zone phase change in workpieces, and temperature and magnetic fields in the electrodes of different geometries. The predicted nugget thickness and dynamic resistance versus time show quite good agreement with available experimental data. Excluding expulsion, the dynamic resistance curve can be divided into four stages. A rapid decrease of dynamic resistance in stage 1 is attributed to decreases in contact resistances at the faying surface and electrode-workpiece interface. In stage 2, the increase in dynamic resistance results from the primary increase of bulk resistance in the workpieces and an increase of the sum of contact resistances at the faying surface and electrode-workpiece interface. Dynamic resistance in stage 3 decreases, because increasing rate of bulk resistance in the workpieces and contact resistances decrease. In stage 4 the decrease of dynamic resistance is mainly due to the formation of the molten nugget at the faying surface. The molten nugget is found to occur in stage 4 rather than stage 2 or 3 as qualitatively proposed in the literature. The effects of different parameters on the dynamic resistance curve are also presented.

On-line Quality Estimation in Resistance Spot Welding

1999 ◽  
Vol 122 (3) ◽  
pp. 511-512 ◽  
Author(s):  
Wei Li ◽  
S. Jack Hu ◽  
Jun Ni
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Selection Procedure ◽  
Resistance Force ◽  
Dynamic Resistance ◽  
Electrode Wear ◽  
Size Estimation ◽  
Resistance Spot ◽  
Electrode Displacement ◽  
On Line

A neural network model is developed for on-line nugget size estimation in resistance spot welding. The variables used consist of features extracted from both controllable process input variables and on-line signals. A systematic signal and feature selection procedure is developed. The three commonly observed on-line signals, dynamic resistance, force, and electrode displacement, have been proven to carry similar information. Thus, only dynamic resistance is used in the model. The obtained model has been demonstrated to be robust over various welding conditions including electrode wear. [S1087-1357(00)01204-1]

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