Analysis of Weld Formation in Multilayer Ultrasonic Metal Welding Using High-Speed Images

2015 ◽  
Author(s):  
S. Shawn Lee ◽  
Tae Hyung Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Welding Process ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Tool Geometry ◽  
Weld Quality ◽  
Weld Formation ◽  
Welding Processes

One of the major challenges in manufacturing automotive lithium-ion batteries and battery packs is to achieve consistent weld quality in joining multiple layers of dissimilar materials. While most fusion welding processes face difficulties in such joining, ultrasonic welding stands out as the ideal method. However, inconsistency of weld quality still exists because of limited knowledge on the weld formation through the multiple interfaces. This study aims to establish real-time phenomenological observation on the multilayer ultrasonic welding process by analyzing the vibration behavior of metal layers. Such behavior is characterized by a direct measurement of the lateral displacement of each metal layer using high-speed images. Two different weld tools are used in order to investigate the effect of tool geometry on the weld formation mechanism and the overall joint quality. A series of microscopies and bond density measurements is carried out to validate the observations and hypotheses of those phenomena in multilayer ultrasonic welding. The results of this study enhance the understanding of the ultrasonic welding process of multiple metal sheets and provide insights for optimum tool design to improve the quality of multilayer joints.

Analysis of Weld Formation in Multilayer Ultrasonic Metal Welding Using High-Speed Images

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
S. Shawn Lee ◽  
Tae Hyung Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Welding Process ◽  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Tool Geometry ◽  
Weld Quality ◽  
Weld Formation ◽  
Welding Processes

One of the major challenges in manufacturing automotive lithium-ion batteries and battery packs is to achieve consistent weld quality in joining multiple layers of dissimilar materials. While most fusion welding processes face difficulties in such joining, ultrasonic welding stands out as the ideal method. However, inconsistency of weld quality still exists because of limited knowledge on the weld formation through the multiple interfaces. This study aims to establish real-time phenomenological observation on the multilayer ultrasonic welding process by analyzing the vibration behavior of metal layers. Such behavior is characterized by a direct measurement of the lateral displacement of each metal layer using high-speed images. Two different weld tools are used in order to investigate the effect of tool geometry on the weld formation mechanism and the overall joint quality. A series of microscopies and bond density measurements is carried out to validate the observations and hypotheses of those phenomena in multilayer ultrasonic welding. The results of this study enhance the understanding of the ultrasonic welding process of multiple metal sheets and provide insights for optimum tool design to improve the quality of multilayer joints.

Characterization of Joint Quality in Ultrasonic Welding of Battery Tabs

2012 ◽  
Author(s):  
S. Shawn Lee ◽  
Tae H. Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Scientific Quality ◽  
Weld Quality ◽  
Ultrasonic Metal Welding ◽  
Quality Guidelines ◽  
State Process ◽  
Metal Welding ◽  
Welding Processes

Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining such as welding to meet desired power and capacity needs. However, conventional fusion welding processes such as resistance spot welding and laser welding face difficulties in joining multiple sheets of highly conductive, dissimilar materials with large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.

Characterization of Joint Quality in Ultrasonic Welding of Battery Tabs

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
S. Shawn Lee ◽  
Tae Hyung Kim ◽  
S. Jack Hu ◽  
Wayne W. Cai ◽  
Jeffrey A. Abell ◽  
...  
Keyword(s):  
Lithium Ion ◽  
Ultrasonic Welding ◽  
Fusion Welding ◽  
Scientific Quality ◽  
Weld Quality ◽  
Ultrasonic Metal Welding ◽  
Quality Guidelines ◽  
State Process ◽  
Metal Welding ◽  
Welding Processes

Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining, such as welding, to meet the desired power and capacity needs. However, conventional fusion welding processes, such as resistance spot welding and laser welding, face difficulties in joining multiple sheets of highly conductive, dissimilar materials to create large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time using copper-to-copper welding as an example. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.

Dynamics of Battery Tabs Under Ultrasonic Welding

2013 ◽  
Author(s):  
Bongsu Kang ◽  
Wayne Cai ◽  
Chin-An Tan
Keyword(s):  
Longitudinal Vibration ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Point Of View ◽  
Structural Vibration ◽  
Kinetic Properties ◽  
Weld Quality ◽  
Ultrasonic Metal Welding ◽  
Metal Welding ◽  
Welding Processes

Ultrasonic metal welding for battery tabs must be performed with 100% reliability in battery pack manufacturing as the failure of a single weld essentially results in a battery that is inoperative or cannot deliver the required power due to the electrical short caused by the failed weld. In ultrasonic metal welding processes, high-frequency ultrasonic energy is used to generate an oscillating shear force (sonotrode force) at the interface between a sonotrode and few metal sheets to produce solid-state bonds between the sheets clamped under a normal force. These forces, which influence the power needed to produce the weld and the weld quality, strongly depend on the mechanical and structural properties of the weld parts and fixtures in addition to various welding process parameters such as weld frequencies and amplitudes. In this work, the effect of structural vibration of the battery tab on the required sonotrode force during ultrasonic welding is studied by applying a longitudinal vibration model for the battery tab. It is found that the sonotrode force is greatly influenced by the kinetic properties, quantified by the equivalent mass and equivalent stiffness, of the battery tab and cell pouch interface. This study provides a fundamental understanding of battery tab dynamics during ultrasonic welding and its effects on weld quality, and thus provides useful guidelines for design and welding of battery tabs from tab dynamics point of view.

Microstructure and Mechanical Properties of Friction Stir Welded AA6060-T6 Tubes

2013 ◽  
Vol 554-557 ◽  
pp. 977-984 ◽  
Author(s):  
Gianluca D'Urso ◽  
Michela Longo ◽  
Claudio Giardini
Keyword(s):  
Welding Process ◽  
Tensile Tests ◽  
Fusion Welding ◽  
Welding Parameters ◽  
External Diameter ◽  
Weld Quality ◽  
Cnc Machine ◽  
Friction Stir ◽  
Aluminum Tubes ◽  
Welding Processes

Friction stir welding (FSW) has received increasing attention in recent years thanks to its advantages over traditional welding processes, reducing distortion and eliminating solidification defects. Since melting does not take place and joining occurs below the melting temperature of the material, this welding process allows to obtain a weld characterized by very high quality with low heat input, minimal distortion, no filler material, and no fumes. FSW is also highly efficient and it is characterized by improved environmental performance if compared to traditional welding methods. For instance, FSW is particularly advantageous in the pipeline industry because this innovative welding process usually entails reduction in energy usage of up to 80% if compared to conventional fusion welding processes. Moreover, also alloys normally difficult to be welded can be considered with this technique. The objective of the present study is to establish and to study the weldability of aluminum tubes by means of FSW process. The study shows preliminary results on circumferential FSW of AA6060-T6 aluminum tubes and the influence of the welding process on weld quality. The experimental campaign was performed on tubes having a thickness equal to 5 mm and an external diameter equal to 80 mm. Tubes were welded by means of a four axes CNC machine tool. Particular care was paid to the fabrication of the inner support for the tube. The mandrel was designed in order to guarantee limited bending during the welding process. Some preliminary tests were carried out by varying the welding parameters, namely feed rate (f) and rotational speed (S). A tool having conical shoulder and cylindrical pin was used. The weld quality investigation was based on tensile tests, microhardness and macrostructure analysis of the joints.

Dynamic Response of Battery Tabs Under Ultrasonic Welding

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Bongsu Kang ◽  
Wayne Cai ◽  
Chin-An Tan
Keyword(s):  
Longitudinal Vibration ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Structural Vibration ◽  
Kinetic Properties ◽  
Weld Quality ◽  
Equivalent Viscous Damping ◽  
Ultrasonic Metal Welding ◽  
Metal Welding ◽  
Welding Processes

Ultrasonic metal welding (USMW) for battery tabs must be performed with 100% reliability in battery pack manufacturing as the failure of a single weld essentially results in a battery that is inoperative or cannot deliver the required power due to the electrical short caused by the failed weld. In ultrasonic metal welding processes, high-frequency ultrasonic energy is used to generate an oscillating shear force (sonotrode force) at the interface between a sonotrode and few metal sheets to produce solid-state bonds between the sheets clamped under a normal force. These forces, which influence the power needed to produce the weld and the weld quality, strongly depend on the mechanical and structural properties of the weld parts and fixtures in addition to various welding process parameters, such as weld frequencies and amplitudes. In this work, the effect of structural vibration of the battery tab on the required sonotrode force during ultrasonic welding is studied by applying a longitudinal vibration model for the battery tab. It is found that the sonotrode force is greatly influenced by the kinetic properties, quantified by the equivalent mass, equivalent stiffness, and equivalent viscous damping, of the battery tab and cell pouch interface. This study provides a fundamental understanding of battery tab dynamics during ultrasonic welding and its effect on weld quality, and thus provides a guideline for design and welding of battery tabs from tab dynamics point of view.

Effects of Wire Rotating Frequency on Metal Transfer Process in Rotating Arc Narrow Gap Horizontal GMAW

2011 ◽  
Vol 189-193 ◽  
pp. 3395-3399 ◽  
Author(s):  
Ning Guo ◽  
Yan Fei Han ◽  
Chuan Bao Jia ◽  
Yong Peng Du
Keyword(s):  
Transfer Process ◽  
High Speed ◽  
Stable Process ◽  
Welding Process ◽  
Metal Transfer ◽  
Welding Parameters ◽  
High Speed Photography ◽  
Narrow Gap ◽  
Weld Formation ◽  
Rotating Arc

The metal transfer process with different welding parameters in rotating arc narrow gap horizontal welding is successfully observed by the high-speed photography system. The effects of wire rotating frequency on metal transfer process in rotating arc narrow gap horizontal welding are novelly explored. The metal transfer with different wire rotating frequency presents different modes. The results indicate that the droplet transfer has stable process with the rotating frequency of 5-20 Hz. And the weld formation is quite shapely. But with the high rotating frequency of 50 Hz, the metal transfer process is not acceptable and the weld formation is very pool. Metal transfer process is one of the most important factors of effecting the weld formation in rotating arc horizontal welding process besides the molten pool behavior and welding thermal circles.

Phenomenological Modeling of Fusion Welding Processes

MRS Bulletin ◽  
1994 ◽  
Vol 19 (1) ◽  
pp. 29-35 ◽  
Author(s):  
S.A. David ◽  
T. DebRoy ◽  
J.M. Vitek
Keyword(s):  
Solid State ◽  
Heat Source ◽  
Base Metal ◽  
Weld Pool ◽  
Welding Process ◽  
Poor Performance ◽  
Consumer Products ◽  
Phase Changes ◽  
Fusion Welding ◽  
Welding Processes

Welding is utilized in 50% of the industrial, commercial, and consumer products that make up the U.S. gross national product. In the construction of buildings, bridges, ships, and submarines, and in the aerospace, automotive, and electronic industries, welding is an essential activity. In the last few decades, welding has evolved from an empirical art to a more scientifically based activity requiring synthesis of knowledge from various disciplines. Defects in welds, or poor performance of welds, can lead to catastrophic failures with costly consequences, including loss of property and life.Figure 1 is a schematic diagram of the welding process showing the interaction between the heat source and the base metal. During the interaction of the heat source with the material, several critical events occur: melting, vaporization, solidification, and solid-state transformations. The weldment is divided into three distinct regions: the fusion zone (FZ), which undergoes melting and solidification; the heat-affected zone (HAZ) adjacent to the FZ, that may experience solid-state phase changes but no melting; and the unaffected base metal (BM).Creating the extensive experimental data base required to adequately characterize the highly complex fusion welding process is expensive and time consuming, if not impractical. One recourse is to simulate welding processes either mathematically or physically in order to develop a phenomenological understanding of the process. In mathematical modeling, a set of algebraic or differential equations are solved to obtain detailed insight of the process. In physical modeling, understanding of a component of the welding process is achieved through experiments designed to avoid complexities that are unrelated to the component investigated.In recent years, process modeling has grown to be a powerful tool for understanding the welding process. Using computational modeling, significant progress has been made in evaluating how the physical processes in the weld pool influence the development of the weld pool and the macrostructures and microstructures of the weld.

Numerical Study of the Tool Rake Angle Effect on the Material Flow in Friction Stir Welding Process

2007 ◽  
Author(s):  
Hosein Atharifar ◽  
Radovan Kovacevic
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Numerical Study ◽  
Welding Process ◽  
Rake Angle ◽  
Heat Transfer Analysis ◽  
Tool Geometry ◽  
Friction Stir ◽  
Tool Pin ◽  
Welding Processes

Minimizing consumed energy in friction stir welding (FSW) is one of the prominent considerations in the process development. Modifications of the FSW tool geometry might be categorized as the initial attempt to achieve a minimum FSW effort. Advanced tool pin and shoulder features as well as a low-conductive backing plate, high-conductive FSW tools equipped with cooling fins, and single or multi-step welding processes are all carried out to achieve a flawless weld with reduced welding effort. The outcomes of these attempts are considerable, primarily when the tool pin traditional designs are replaced with threaded, Trifiute or Trivex geometries. Nevertheless, the problem remains as to how an inclined tool affects the material flow characteristics and the loads applied to the tool. It is experimentally proven that a positive rake angle facilitates the traverse motion of the FSW tool; however, few computational evidences were provided. In this study, numerical material flow and heat transfer analysis are carried out for the presumed tool rake angle ranging from −4° to 4°. Afterwards, the effects of the tool rake angle to the dynamic pressure distribution, strain-rates, and velocity profiles are numerically computed. Furthermore, coefficients of drag, lift, and side force and moment applied to the tool from the visco-plastic material region are computed for each of the tool rake angles. Eventually, this paper confirms that the rake angle dramatically affects the magnitude of the loads applied to the FSW tool, and the developed advanced numerical model might be used to find optimum tool rake angle for other aluminum alloys.

The Effect of the Material and the Geometric Shape of the Waveguides on the Process of Ultrasonic Welding of Plastics

2019 ◽  
pp. 25-32
Author(s):  
S.S. Volkov ◽  
V.M. Nerovnyy ◽  
G.A. Bigus
Keyword(s):  
Welding Process ◽  
Polymeric Materials ◽  
Ultrasonic Welding ◽  
Wave Resistance ◽  
Tool Geometry ◽  
Acoustic Characteristics ◽  
Oscillatory Systems ◽  
Materials Used ◽  
Quality Of Products

This article briefly describes basic elements of machines for ultrasonic welding of plastics and the main materials used for manufacturing elements of ultrasonic waveguide oscillatory systems. A relationship between the amplitude of fluctuations of the welded material and a ratio of wave resistance of the product material and the waveguide tool geometry is examined. It is shown that when welding plastic products of a large thickness, it is practical to use waveguides made from aluminum alloys with a working end face with a diameter of 15 mm. It is established that the closer the acoustic characteristics of the waveguide material and the plastic are, the fuller the transfer of ultrasonic energy is when transiting through the interface of the welded polymeric materials. To assess the distribution of amplitudes of fluctuations in the welded material it is more convenient to use a transmission ratio, which decreases with a decrease in the wave resistance. It is established that the sizes of the working end face of the waveguide are most often defined by the properties, dimensions and geometry of the welded product. The application of the developed recommendations to the choice of material and sizes of the working end face of the waveguide can increase technological reliability of the ultrasonic welding process and improve quality of products.

Sign in / Sign up

Export Citation Format

Share Document