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.

Modelling resistance welding of thermoplastic composites with a nanocomposite heating element

2020 ◽  
pp. 002199832095705
Author(s):  
David Brassard ◽  
Martine Dubé ◽  
Jason R Tavares
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Welding Process ◽  
Element Model ◽  
Resistance Welding ◽  
Thermoplastic Composites ◽  
Process Window ◽  
Cohesive Failure ◽  
Electrically Conductive ◽  
Lap Shear

Electrically conductive nanocomposite heating elements are being developed as a complement to traditional carbon fibre or stainless steel heating elements in resistance welding of thermoplastic composites. Here we present the development of a finite element model of the resistance welding process with these new heating elements, from which we establish a process window for high quality welded joints. The finite element model results were validated experimentally and a lap shear strength improvement of 28% is reported relative to previously published results. Fractography analysis of the broken joints revealed a thin-layer cohesive failure mode due to the brittleness of the nanocomposite heating elements.

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.

Experimental Study on the Single-Sided Double-Point Resistance Welding of Bus Roof Skin

2014 ◽  
Vol 680 ◽  
pp. 97-101
Author(s):  
Hai Bin Huang ◽  
Jian Chun Liu ◽  
Xiao Long Ke ◽  
Xiao Hui Lin
Keyword(s):  
Double Point ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Welding Current ◽  
Resistance Welding ◽  
Galvanized Steel ◽  
Low Carbon ◽  
Support Mechanism ◽  
Experiment Platform ◽  
Weld Area

In order to weld the skin and skeleton of bus roof, it analysis the welding process of bus Outer Roof-panels , and specify the weld area and solder joint distance of outer roof-panel firstly , then built a single-sided double-point resistance welding experiment platform for bus outer roof-panels, the platform consists of guide、gantry、gantry moving mechanism、 pneumatic torch、electrode support mechanism、transformers、torch lateral movement organizations and torch longitudinal movement phenomenon . it set the unevenness of the skin and the skeleton as 1mm, single-sided double-point resistance welding experiment was conducted on the welding experiment platform. The experimental results of welding area visual examination and tear experiments indicate that welding heat will penetrate the skeleton when the welding current is greater than 11.0KA;the welding Reliability of galvanized steel is better than low carbon steel.

scholarly journals Design and Fabrication of Remote Welding Equipment in a Hot-Cell

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Soosung Kim ◽  
Kihwan Kim ◽  
Jungwon Lee ◽  
Jinhyun Koh
Keyword(s):  
Nuclear Fuel ◽  
Performance Test ◽  
Preliminary Investigation ◽  
Welding Process ◽  
Resistance Welding ◽  
Welding Equipment ◽  
End Plate ◽  
Fuel Fabrication ◽  
Fuel Bundle ◽  
Remote Welding

The remote welding equipment for nuclear fuel bundle fabrication in a hot-cell was designed and developed. To achieve this, a preliminary investigation of hands-on fuel fabrication outside a hot-cell was conducted with a consideration of the constraints caused by the welding in a hot-cell. Some basic experiments were also carried out to improve the end-plate welding process for nuclear fuel bundle fabrication. The resistance welding equipment using end-plate welding was also improved. It was found that the remote resistance welding was more suitable for joining an end-plate to end caps in a hot-cell. This paper presents an outline of the developed welding equipment for nuclear fuel bundle fabrication and reviews a conceptual design of remote welding equipment using a master-slave manipulator. Furthermore, the mechanical considerations and a mock-up simulation test were described. Finally, its performance test results were presented for a mock-up of the remote resistance welding equipment for nuclear fuel bundle fabrication.

scholarly journals Connection Status Research of the Resistance Spot Welding Joint Based on a Rectangular Terminal Electrode

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 659
Author(s):  
Xiaoqi Zhang ◽  
Lingbo Wei ◽  
Guocheng Xu ◽  
Chunsheng Wang
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Process Analysis ◽  
Welding Process ◽  
Welding Current ◽  
Welding Parameters ◽  
Current Time ◽  
Axis Direction ◽  
Resistance Spot ◽  
Welding Pressure

Rectangular terminal electrode is adopted in this research to conduct a resistance spot welding (RSW) process on stainless steel plate. The connection status of RSW joints under different welding current, time, and pressure were studied, and revealed how the rectangular terminal electrode shape and its dimensions influence the RSW joint dimensions. The process analysis results showed that the RSW nuggets welded with rectangular terminal electrode are normally elliptical in shape, and the dimensions of the long axis direction and the short axis direction have a certain proportion. As the welding current increases, the nuggets dimensions in long direction increase first and then decrease, and the internal grain structure also varies. As the welding time increases, the nugget size in long direction increase first and then steady and rarely splash occurs. As the welding pressure increase, the nugget dimensions in long direction increase first and then decrease, and the splash easily occurs under large welding pressure. However, when the welding pressure is too small, the unique adjacent double fusion nugget formed. By adopting proper welding parameters, the nugget size and quality can be controlled. This provides an important basis for the application of rectangular terminal electrode in RSW welding process.

Ultrasonic plastic welding of CF/PA6 composites to aluminium: Process and mechanical performance of welded joints

2019 ◽  
Vol 53 (18) ◽  
pp. 2607-2621 ◽  
Author(s):  
Umberto F Dal Conte ◽  
Irene F Villegas ◽  
Julien Tachon
Keyword(s):  
Mechanical Performance ◽  
Lightweight Design ◽  
Welding Process ◽  
Thermoplastic Composites ◽  
Process Time ◽  
Reinforced Plastics ◽  
Lap Shear ◽  
Physical Treatments ◽  
Reinforced Thermoplastics ◽  
Plastic Welding

Due to environmental challenges and need for action with regard to CO2 emission, reducing the weight of vehicles has become one of the most important goals of car manufacturers in Europe. Materials like fibre-reinforced plastics and aluminium are the core of the research for lightweight design. However, efficiently joining these materials together is still a challenge. When thermoplastic composites are used, direct joining (i.e. without adhesives or fasteners) with the metal substrate can be obtained using welding technologies which melt the thermoplastic at the interface. In this study, ultrasonic plastic welding was investigated as a candidate technology for joining aluminium and carbon fibre-reinforced thermoplastics. The goal was to understand the main mechanisms involved in the welding process and how they affect the performance of the joint. Initially, the technique proved to be successful, but moderate strengths were obtained. Therefore, several surface pre-treatments of aluminium were analysed to improve the performance in terms of lap shear strength; mechanical, chemical and physical treatments were also carried out. With laser structuring, strengths comparable to adhesive bonded joints were obtained, but in a much shorter process time. Other treatments led to considerable improvements as well. The encouraging results achieved represent an important step in the development of ultrasonic plastic welding for multi-material joining in the automotive industry.

scholarly journals Bonding of High Temperature Thermoplastic Carbon Composites with Resistance Welding Technique

2018 ◽  
Vol 2018 (3) ◽  
pp. 1-13
Author(s):  
Przemysław Dobrzański
Keyword(s):  
State Of The Art ◽  
Ultrasonic Method ◽  
Welding Process ◽  
Thermoplastic Composite ◽  
Resistance Welding ◽  
Thermoplastic Composites ◽  
Carbon Composites ◽  
Pressure Application ◽  
Welding Technology ◽  
Welding Technique

Abstract The article presents ‘state-of-the art’ on joining fibre reinforced thermoplastic composites with the use of resistance welding technique. Their welding process and potential difficulties connected with the process and quality control of a manufactured element are presented. The structure of a typical thermoplastic composite welding stand was also presented. The main welding technology elements were characterized: structure of the resistance element, implementation of the thermal process and pressure application required for joining materials. The paper also presents the required calibration ranges for a technological process with the use of strength test types SLS, DCB, SBS and nondestructive testing of joint with the ultrasonic method.

scholarly journals Joining of Thermoplastic Composites with Metals Using Resistance Element Welding

2020 ◽  
Vol 10 (20) ◽  
pp. 7251 ◽  
Author(s):  
Juliane Troschitz ◽  
Julian Vorderbrüggen ◽  
Robert Kupfer ◽  
Maik Gude ◽  
Gerson Meschut
Keyword(s):  
Welding Process ◽  
Thermoplastic Composites ◽  
Innovative Technology ◽  
Welding Parameters ◽  
Compression Moulding ◽  
Steel Sheets ◽  
Lap Shear ◽  
Before And After ◽  
Resistance Element Welding ◽  
Glass Fibre Reinforced

Joining is a key enabler for a successful application of thermoplastic composites (TPC) in future multi-material systems. To use joining technologies, such as resistance welding for composite-metal joints, auxiliary joining elements (weld inserts) can be integrated into the composite and used as an interface. The authors pursue the approach of embedding metal weld inserts in TPC during compression moulding without fibre damage. The technology is based on the concept of moulding holes by a pin and simultaneously placing the weld insert in the moulded hole. Subsequently, the composite component can be joined with metal structures using conventional spot welding guns. For this purpose, two different types of weld inserts were embedded in glass fibre reinforced polypropylene sheets and then welded to steel sheets. A simulation of the welding process determined suitable welding parameters. The quality of the joints was analysed by microsections before and after the welding process. In addition, the joint strength was evaluated by chisel tests as well as single-lap shear tests for the different weld insert designs. It could be shown that high-quality joints can be achieved by using the innovative technology and that the load-bearing capacity is significantly influenced by the weld inserts head design.

Enhanced adhesion between PEEK and stainless-steel mesh in resistance welding of CF/PEEK composites by various surface treatments

2021 ◽  
pp. 095400832110011
Author(s):  
Xuekuan Li ◽  
Mingchen Sun ◽  
Jiupeng Song ◽  
Tong Zhang ◽  
Yan Zhao ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Shear Strength ◽  
Energy Dispersive Spectrometer ◽  
Welding Process ◽  
Surface Treatments ◽  
Interfacial Bonding ◽  
Resistance Welding ◽  
Stainless Steel Mesh ◽  
Steel Mesh ◽  
Lap Shear

In order to improve the interfacial adhesion of stainless-steel mesh reinforced poly(ether-ether-ketone) (SSM/PEEK) heating elements (HEs) used in the resistance welding process for continuous carbon fiber reinforced PEEK composites (CF/PEEK composites), three kinds of surface treatments, sandblasting, aryl diazonium grafting and silane grafting, were adopted on SSM surfaces. The functional groups were grafted successfully according to the Fourier Transform Infrared (FTIR) results and Energy Dispersive Spectrometer (EDS) results, and the surface morphologies of SSM changed significantly after different treatments. Although the tensile performances of sandblasted stainless-steel (SS) wire and sandblasted SSM were distinctly reduced, the lap shear strength (LSS) of joints with sandblasted SSM still slightly improved. Besides, the interfacial shear strength (IFSS) increased from 28 MPa for untreated SSM to 34 MPa for diazonium grafted SSM and 38 MPa for silane grafted SSM. Furthermore, the LSS results were in agreement with this trend, representing a 9% improvement for joints with diazonium grafted SSM and a 23% improvement for joints with silane grafted SSM compared with untreated CF/PEEK joints. After comparison, silane grafting was the most suitable surface modification for resistance-welded CF/PEEK joints. The interfacial bonding mechanism of CF/PEEK joints with silane grafted SSM was compared with that of untreated CF/PEEK joints, suggesting that the mechanical interlocking contributed to improved interfacial bonding.

scholarly journals ROBOTIC SEQUENTIAL ULTRASONIC WELDING OF THERMOPLASTIC COMPOSITES: PROCESS DEVELOPMENT AND TESTING

2021 ◽  
Author(s):  
ABHAS CHOUDHARY, ◽  
IRENE FERNANDEZ
Keyword(s):  
Welded Joints ◽  
Industrial Robot ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Robot Arm ◽  
Spot Welds ◽  
Robotic Platform ◽  
Lap Shear

Multi-spot sequential ultrasonic welding is a promising joining technique for fibre-reinforced thermoplastic composites structures (TPC). In existing research on the multi-spot sequential ultrasonic welding process, welds are produced through the use of a static table-top welding machine, at a coupon level. However, in order to apply this joining technology to large structures, the welding process needs to be up-scaled through the use of a robotic platform. At the Smart Advanced Manufacturing (SAM|XL) automation field lab and TU Delft Aerospace Engineering, a robotic sequential ultrasonic welding system has been developed. The system consists of a welding end-effector (EEF) equipped with various sensors that enable online process monitoring and control, which can be mounted on an industrial robot arm to perform sequential multi-spot welds. The goal of this study was to assess the welding performance of the ultrasonic welding EEF, which was mounted on an industrial KUKA KR210 R2700 Extra 10-axis robot arm, by comparing it to the performance of welds produced through the static table-top machine. In this study, single and multi-spot welds were produced on thermoplastic composite coupons, based on welding conditions which were defined in a preliminary study. The robot and EEF deflections observed during the welding process were analysed to assess the deviation of the robotic process from the static one. The feedback obtained from the welding equipment in terms of consumed power and tool displacement in both processes was also compared. The weld quality was assessed though single lap shear testing of the welded joints as well as fractography of the failure surface. The results of this study indicate that the developed robotic welding process is quite robust and is capable of producing high-quality sequential welded joints despite significant system deflections observed during the welding process. Slightly lower welded area and weld strength was obtained which can be attributed to the system deflections. Finally, the results indicate that the use of a stiffer robotic platform as well as a stiffer EEF construction will result in better system rigidity and weld spot positioning accuracy, and through this the welding process shows promise for large-scale industrial applications.

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