Energy Analysis during Ultrasonic Welding of PP: EDS-ABS Polymer Blends – Experimental Investigation, Statistical Assessment and Mathematical Modelling for Energy and Power Signal Dynamics

In this paper, the dissimilar joining of Poly Lactic Acid (PLA) with Cork Wood (CW) particles reinforced Poly Lactic Acid (CW/PLA) was made by using an Ultrasonic Welding (UW) process. The single lap joint was made to analyse the better joining with good adhesion between the neat polymer and Cork PLA polymer composite. The objective of this study is to formulate a good bonding of neat biodegradable polymeric material with Cork wood particles reinforced composite with concern to the UW factors like Ultrasonic Amplitude (UA), Welding Pressure (WP), and Welding Time (WT). The experimental trial was carried out by altering the levels of UW factors such as UA (25, 28 and 31 µm), WP (0.10, 0.15 and 0.20 MPa), and WT (1, 1.3 and 1.5 sec) with respect to attainment the higher lap shear strength. The statistical optimization methods, including Taguchi and Analysis of Variance, are employed to identify the optimum factors for the welding process and evaluate the proportional impact of the UW factors. The results revealed that the UA of 28 µm, WP of 0.15 MPa, and WT of 1.5 sec exhibits the higher lap shear strength of 24.16 MPa. For the optimized condition, the interface hardness was measured using the Shore D hardness method. The results imply that the maximum interface hardness of 75 was observed at the weld centre. Fractured samples clearly show that interfacial failure is absent, this dictates the weld regions are strong enough to hold the applied load. The developed regression model for the present UW process on the PLA and Cork wood PLA composite is significant and has an R2 value of 92.8%. So, the developed model is suitable for converting into large-scale industrial production and applications.

Ultrasonic metal spot welding (USMW) is a well-known solid-state joining process for bonding non-ferrous metals without using any filler materials. The joining of dissimilar materials such as aluminum, nickel, copper, magnesium is difficult by fusion welding processes due to its higher thermal, chemical, and physical properties. However, USMW yields better quality of joints under the influence of optimal parametric conditions. The flexibility of using this method is still restricted because of insufficient scientific understanding and unwanted intermetallic compound formation in the weld interface. The current study is focused on the weld strength and failure behavior of ultrasonic spot-welded aluminum (AA1100) and pure nickel joints at different weld parametric conditions, i.e., weld time, weld pressure, and vibration amplitude. From the mechanical analysis, the tensile shear failure load of the welded specimen is highest at the maximum vibration amplitude with a balanced amount of weld pressure and weld time. It is also noticed that these joint strengths decreased with the further increase of weld time or weld pressure because of excessive interface temperature rise. It results in the softening of base material and more amount of interfacial diffusion occurred in the weld region. The microstructural morphologies at the weld region disclose various types of weld characteristics such as mechanical interlocking zone, wavy pattern region, and swirling like diffusion area at the weld interface.

Energy crisis poses a major challenge in the modern industrial scenario. A critical aspect of the shop floor work includes the welding of dissimilar metal sheets which require the right amount of energy. In order to tackle these challenges, a conservative and energy efficient method are necessary. Recently, automotive industries have been widely adopted the ultrasonic metal welding process for assembling lithium-ion battery packs and its modules. The joining of these dissimilar metals using any other conventional welding process is extremely challenging due to varying physical, chemical, thermal properties, the formation of the heat affected zone and lesser bond strength. However, ultrasonic metal welding yields better quality welds under the influence of optimal parametric conditions. In this research, the weld quality of two dissimilar materials, namely, aluminum (AA1060) with cupronickel (C71500) sheets investigated at different welding time, vibration amplitudes and welding pressures with a fixed ultrasonic frequency of 20 kHz. Experimental results show the tensile shear strength of the weld is maximum at the highest vibration amplitude with a moderate amount of weld pressure and weld time. Additionally, the joint quality and its associated microstructure at the weld region are analyzed by scanning electron microscopy (SEM) to reveal the bond strength with the interlocking feature.

This paper gives a description of an experimental study on the ultrasonic welding of metals. In ultrasonic metal welding, high frequency vibrations are combined with pressure to join two materials together quickly and securely, without generating large amount of heat. Horn, a key part of ultrasonic welding machine, should be designed very accurately to get the natural frequencies and vibration mode required. In this study, a horn is designed and developed for ultrasonic welding of Cu sheets. The tensile strength of welded parts is investigated for evaluation of weldability. Experimental parameters of welding test is set as follows; welding time 0.4s ~ 3.4sec. and vibration amplitude 40%, 60%, 80% and welding pressure 1.5bar, 2.0bar, 2.5bar. Samples are Cu sheets of 0.1mm thickness. Experimental results showed that the tensile strength increase as welding parameters increase, but when welding pressure is excessive, the tensile strength decrease due to fracture of the Cu sheets caused by over-welding. These results could be successfully applied for ultrasonic metal welding in various fields of manufacturing industry.

Ultrasonic welding is a solid-state joining process that produces joints by the application of high-frequency vibratory energy in the work pieces held together under pressure without melting. In electronic and automotive applications, copper wires are connected to the equipment (alternator/rectifier) by a solid state joining process. For such an application ultrasonic metal welding is useful. The dominant problem faced by industry dealing with ultrasonic metal welding process is the poor weld quality and strength of the weld due to improper selection of weld parameters. In this work welding parameters like welding pressure, weld time and amplitude of the vibration are considered while producing ultrasonically welded joints of copper whose thickness is 0.2 mm. If other modes of joining are used, this size being very small, it may damage the weld. A suitable experimental design based on Taguchi’s robust design methodology was designed and executed for conducting trials. The analysis of variance (ANOVA) and signal to noise ratio analyses are employed to investigate the influence of different welding parameters on the weld strength and to obtain the optimum parameters.

Chapter three - Weldability appraisement of dissimilar metal joints: application of ultrasonic spot welding to Li-ion batteries

Glass fiber reinforced polypropylene composites were joined by ultrasonic welding, employing various weld conditions. Single-lap shear testing was used to evaluate the effect of weld time and weld pressure on the weld performance. The weld strength increased with increasing weld time and weld pressure until a plateau or maximum strength was reached. The required weld time to obtain a complete weld became shorter when the weld pressure was increased. As lower weld pressure was applied, a complete weld could not be obtained unless relatively longer weld times were employed. A welding map, showing conditions of weld time and weld pressure to get a good weld, was obtained.

Investigation of process parameters of ultrasonic welding of copper using Taguchi and grey relational analysis

The possibility of assembling through welding is one of the major features of thermoplastic composites and it positively contributes to their cost-effectiveness in manufacturing. This article presents a comparative evaluation of ultrasonic, induction and resistance welding of individual carbon fibre-reinforced polyphenylene sulphide (PPS) thermoplastic composite samples that comprises an analysis of the static and dynamic mechanical behaviour of the joints as well as of the main process variables. The induction welding process as used in this research benefitted from the conductive nature of the reinforcing fibres. Hence, no susceptor was placed at the welding interface. Resistance welding used a fine-woven stainless-steel mesh as the heating element and low welding pressures and times were applied to prevent current leakage. Triangular energy directors moulded on a separate tape of PPS resin were used to concentrate ultrasonic heat at the welding interface. The static single-lap shear strength of the joints was found similar for induction and ultrasonic welding. A 15% drop in the static mechanical properties of the resistance welded joints was attributed to incomplete welded overlaps following current leakage prevention. However, the fatigue performance relative to the static one was similar for the three sorts of joints. A comparative analysis of process variables such as welding time, required power and energy was also carried out.

Ultrasonic welding (USW) is a solid-state joining process in which the joint is created between the workpieces by the application of high frequency ultrasonic waves under pressure. Poor weld strength is one of the major problem experienced in the application of such weldments. It is mainly due to improper selection of process parameters. In order to achieve satisfactory weld strength optimization of welding process parameters is indeed essential. In this present context, the USW has been carried out to join dissimilar materials like A1100 aluminum alloy and CuZn37 brass plates of thickness 0.1 mm using Taguchi’s L16 orthogonal array design of experiments. The process parameters like amplitude, weld pressure and weld time have been taken into consideration. Taguchi’s S/N ratio concept has been employed to study the effect of different process parameters on the response like tensile strength; and finally, the optimum setting of process parameters has been decided in view of maximizing tensile strength. The predicted result of the optimized tensile strength has been validated by conducting a confirmatory test. This analysis shows that the high quality and efficient joints can be generated by exploring optimized setting of process parameters which is fruitful in mass production as well as off-line quality control of such a welding practice.

Ultrasonic welding of GF/PA6T composites: Experimental investigation and process optimization

Ultrasonic welding is a welding method that has been applied for welding nonwoven fabrics, with many advantages such as fast speed, high reliability, easy automation and especially less pollution to the environment. This paper studies the optimization of technological parameters in the welding process such as welding time, pressure, and weld shape on the breaking strength of ultrasonic welding of Polypropylene (PP) nonwovens. To evaluate the influence level and find the reasonable technological parameters domain in the paper, the Taguchi method is used in combination with the face-centered central composite design (FCCCD) response surface method. The research results have determined the regression equations used to calculate the breaking strength for each weld shape as well as the optimal domain for the main technological parameters, ensuring the breaking strength of the weld. There are different degrees of influence of technological parameters (shape of the weld zone, welding time and welding pressure) on the breaking strength of ultrasonic welds. Among them, the influence level of welding time t is 45.31 %, the weld shape is Pattern 2 with the rate of 30.03 %, and the welding pressure is 24.66 %. Carrying out a verification test with the welding parameters: t=1.6 s, p=3.1 kgf/cm2, two patterns ( Pattern 2 and Pattern 3), the result of breaking strength for patterns was achieved. Pattern 2 has a difference of 1.19 % between the regression equation results and the actual experimental results, while the figure for Pattern 3 is 0.77 %. From these results, it is possible to select the appropriate technological parameters for ultrasonic welding equipment when processing products from nonwoven fabrics to ensure the highest quality and productivity

Article history: Ultrasonic metal welding, unlike the conventional welding techniques, does not require an external heat source, welding rod, or filler metal. Therefore, ultrasonic metal welding is not only economical but also environment-friendly, and hence, it has been receiving much attention. In ultrasonic welding, heat is generated because of the plastic deformation and the friction between both surfaces of the welded materials. It is important to identify the heat-affected zone by measuring the temperature generated at the weld. In this study, the effects of the welding pressure, welding time, and vibration amplitude on the temperature distribution in the weld were evaluated by performing a transient thermal analysis of the heat generated during ultrasonic metal welding. The experimental results indicated that the temperature of the weld tends to increase with the welding time and vibration amplitude. However, an increase in the pressure does not affect the temperature of the weld largely.

Ultrasonic welding is becoming an essential technique for joining of thin and dissimilar materials in battery electric vehicle manufacturing because of consumption of less power, unmatched weld quality, high production rate, excellent efficiency, etc. The process control parameters in welding play a vital role in getting a good quality weld. In this study, AA1100 aluminum and UNS C10100 copper are utilized for experimentation by controlling three input parameters such as weld pressure, weld time, and vibration amplitude. The effects of these control parameters on the responses like tensile shear and T-peel failure loads of joints with microstructures are revealed. Furthermore, a three-dimensional thermo-mechanical finite element (FE) model with the relevant welding mechanics is proposed for this dissimilar material combination to predict the temperature distribution in its interface, sonotrode, and anvil. The simulation results are validated by comparing the experimental temperature values, and they are showing good agreement with each other. It provides a significant insight of thermal softening phenomenon in ultrasonic welding process and demonstrates the relationship between physical attributes and the interface temperature.

Modeling and optimization of ultrasonic metal welding on dissimilar sheets using fuzzy based genetic algorithm approach