scholarly journals Towards robust sequential ultrasonic spot welding of thermoplastic composites: Welding process control strategy for consistent weld quality

2018 ◽  
Vol 109 ◽  
pp. 355-367 ◽  
Author(s):  
Tian Zhao ◽  
Charlotte Broek ◽  
Genevieve Palardy ◽  
Irene Fernandez Villegas ◽  
Rinze Benedictus
Keyword(s):  
Process Control ◽  
Control Strategy ◽  
Spot Welding ◽  
Welding Process ◽  
Thermoplastic Composites ◽  
Weld Quality

Effect of Electric Weld Current on Spatter Reduction in Spot Welding Process

2004 ◽  
Vol 261-263 ◽  
pp. 1623-1628 ◽  
Author(s):  
Do Won Seo ◽  
Yang Bae Jeon ◽  
Jae Kyoo Lim
Keyword(s):  
Shear Strength ◽  
Spot Welding ◽  
Welding Process ◽  
Weld Quality ◽  
Tensile Shear Strength ◽  
Sheet Metals ◽  
Tensile Shear ◽  
Weld Current ◽  
Electric Weld ◽  
Welding Processes

Spot welding is a process that sheet metals are joined in one or more spot by heating at the faying interface. In this process, the spatter is dispersed from melted area. It has been reported that spatter generation has adverse effects on weld quality. However, no systematic study has been carried out to find out its effect on weld quality in resistance spot welding processes. In this study, specially designed specimens are used to perform experimental investigation of spatter generation and its effect. Major finding of this study show trends in tensile-shear strength for various amounts of spatter generated during spot welding process. Thus, optimum welding conditions are proposed in view of spatter generation and tensile-shear strength.

Online Weld Quality Benchmarking and Assurance during the Mass-Production Resistance Spot Welding Process

2012 ◽  
Vol 443-444 ◽  
pp. 872-880 ◽  
Author(s):  
Liang Gong ◽  
Cheng Liang Liu ◽  
Yan Ming Li ◽  
Bing Chu Li
Keyword(s):  
Quality Assessment ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Bayesian Belief Networks ◽  
Displacement Curve ◽  
Weld Quality ◽  
Probabilistic Forecasting ◽  
Resistance Spot ◽  
Continuous Quality

Nowadays online quality estimation for the resistance spot welding (RSW) has benefited a lot from monitoring the electrode displacement caused by nugget thermal expansion. Based on these emerging monitoring techniques a new approach is proposed to classify the weld quality and assure the quality for mass-produced weld group, which enables the continuous quality improvement concept during the welding process. A causal models are built with the offline trained Bayesian Belief Networks (BBN). It is a weld quality assessment net reveals the dependency of the weld quality on the features displayed by the displacement curve, which can be used for overdesigning the safety welds or as the probabilistic forecasting model for online weld quality assessment. The experimental results show that the proposed approach is valid and feasible to predict the weld quality and assure the overall quality for weld group in real applications.

Application of Fuzzy Logic Control Strategy for Temperature Control in Friction Stir Welding

2013 ◽  
Author(s):  
R. R. Varun Das ◽  
V. Kalaichelvi ◽  
R. Karthikeyan
Keyword(s):  
Fuzzy Logic ◽  
Friction Stir Welding ◽  
Dynamic Modeling ◽  
Temperature Control ◽  
Control Strategy ◽  
Welding Process ◽  
Weld Quality ◽  
Production Environment ◽  
Welding Temperature ◽  
Friction Stir

Friction Stir welding is a solid state joining process that utilizes a rotating non-consumable tool to plastically deform and forge together parent metals. Welding can be controlled either by using Force, Temperature and Traverse or Seam Control methods. The presence of numerous parameters and conditional variations in FSW production environment can adversely affect weld quality making extensive automation processes impossible till date. The weld quality of FSW is closely related to the stability of the welding temperature. For such a non-linear complex process conventional control theory is not an appropriate choice. A fuzzy logic controller with a specially chosen triangular membership function has been suggested as an effective alternative approach. The aim of the present work includes dynamic modeling of a friction stir welding process and the use of a suitable Fuzzy tuned Control Strategy for temperature control. The Temperature at stir zone is measured using a K type Thermocouple. It has a sensitivity of 41μV/°C and also a wide variety of probes are available within its −200° C to +1250 °C range. The thermocouple is used by drilling a hole in the shank of the tool and letting it pass through it. The spindle speed is used as an appropriate variable to control temperature variations. The dynamic modeling and simulations were performed using Matlab whereas the variable values were derived during friction stir welding of aluminum.

THERMOMECHANICAL ANALYSIS OF THE RESISTANCE SPOT-WELDING PROCESS

2018 ◽  
Vol 10 (5) ◽  
pp. 449-455 ◽  
Author(s):  
Habib Lebbal ◽  
Lahouari Boukhris ◽  
Habib Berrekia ◽  
Abdelkader Ziadi
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Thermomechanical Analysis ◽  
Resistance Spot

scholarly journals Multi-Objective Optimization of Resistance Welding Process of GF/PP Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2560
Author(s):  
Guowei Zhang ◽  
Ting Lin ◽  
Ling Luo ◽  
Boming Zhang ◽  
Yuao Qu ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Welding Process ◽  
Welding Current ◽  
Resistance Welding ◽  
Thermoplastic Composites ◽  
Current Time ◽  
Process Factor ◽  
Welding Equipment ◽  
Lap Shear ◽  
Adhesive Connections

Thermoplastic composites (TPCs) are promising materials for aerospace, transportation, shipbuilding, and civil use owing to their lightweight, rapid prototyping, reprocessing, and environmental recycling advantages. The connection assemblies of TPCs components are crucial to their application; compared with traditional mechanical joints and adhesive connections, fusion connections are more promising, particularly resistance welding. This study aims to investigate the effects of process control parameters, including welding current, time, and pressure, for optimization of resistance welding based on glass fiber-reinforced polypropylene (GF/PP) TPCs and a stainless-steel mesh heating element. A self-designed resistance-welding equipment suitable for the resistance welding process of GF/PP TPCs was manufactured. GF/PP laminates are fabricated using a hot press, and their mechanical properties were evaluated. The resistance distribution of the heating elements was assessed to conform with a normal distribution. Tensile shear experiments were designed and conducted using the Taguchi method to evaluate and predict process factor effects on the lap shear strength (LSS) of GF/PP based on signal-to-noise ratio (S/N) and analysis of variance. The results show that current is the main factor affecting resistance welding quality. The optimal process parameters are a current of 12.5 A, pressure of 2.5 MPa, and time of 540 s. The experimental LSS under the optimized parameters is 12.186 MPa, which has a 6.76% error compared with the result predicted based on the S/N.

scholarly journals Static ultrasonic welding of carbon fibre unidirectional thermoplastic materials and the influence of heat generation and heat transfer

2021 ◽  
pp. 002199832097681
Author(s):  
F Köhler ◽  
IF Villegas ◽  
C Dransfeld ◽  
A Herrmann
Keyword(s):  
Cross Sections ◽  
Weld Line ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Squeeze Flow ◽  
Anisotropic Flow ◽  
Lap Shear ◽  
Anisotropic Thermal Conductivity ◽  
Edge Defects

Ultrasonic welding is a promising technology to join fibre-reinforced thermoplastic composites. While current studies are mostly limited to fabric materials the applicability to unidirectional materials, as found in aerospace structures, would offer opportunities for joining primary aircraft structures. However, due to the highly anisotropic flow of a molten unidirectional ply undesired squeeze flow phenomena can occur at the edges of the weld overlap. This paper investigates how the fibre orientation in the plies adjacent to the weld line influences the welding process and the appearance of edge defects. Ultrasonic welding experiments with different layups and energy director configurations were carried out while monitoring temperatures at different locations inside and outside the weld overlap. The joints were characterized by single lap shear tests, analysis of corresponding fracture surfaces and microscopic cross-sections. Results showed that the anisotropic flow and the anisotropic thermal conductivity of the plies adjacent to the weld line have a distinct effect on the appearance and location of edge defects. By using energy directors that cover only part of the weld overlap area a new approach was developed to mitigate edge defects caused by the highly directional properties of the unidirectional plies.

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