Effects of the shape of the energy director on far-field ultrasonic welding of thermoplastics

2000 ◽  
Vol 40 (1) ◽  
pp. 157-167 ◽  
Author(s):  
Yew Khoy Chuah ◽  
Liang-Han Chien ◽  
B. C. Chang ◽  
Shih-Jung Liu
Keyword(s):  
Ultrasonic Welding ◽  
Far Field ◽  
Energy Director

The Effects of Energy Director Shape on Temperature Field during Ultrasonic Welding of Thermoplastic Composites

2007 ◽  
Vol 353-358 ◽  
pp. 2007-2010 ◽  
Author(s):  
Jiu Chun Yan ◽  
Xiao Lin Wang ◽  
Rui Qi Li ◽  
Hui Bin Xu ◽  
Shi Qin Yang
Keyword(s):  
Welding Process ◽  
Element Model ◽  
Ultrasonic Welding ◽  
The Body ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Glass Transformation ◽  
Different Shapes ◽  
Energy Director ◽  
Different Order

The ultrasonic welding process of thermoplastic composite with different shapes of energy director (ED) was simulated using finite element model. The results show that the highest temperature zone locates at the tip for the semicircular and triangular ones, and locates at the middle height for the trapezoid one. But it does not locate at the body of ED for the rectangular one. Energy director with different shapes lead to the temperature rising rate at different order of amplitude. The welding amplitude has same influence on the four shapes of ED. The temperature distributing profiles of semicircular, triangular and trapezoid ED keep constant from the initial welding time to that when the highest temperature on joints arrives the temperature of glass transformation (Tg), but the profile for rectangular ED changes greatly.

scholarly journals Numerical Simulation of Ultrasonic Welding for CFRP Using Energy Director

2020 ◽  
Vol 46 (4) ◽  
pp. 130-136
Author(s):  
Kodai WAKAYAMA ◽  
Kotaro UEHARA ◽  
Jun KOYANAGI ◽  
Shinichi TAKEDA
Keyword(s):  
Numerical Simulation ◽  
Ultrasonic Welding ◽  
Energy Director

scholarly journals Ultrasonic welding of epoxy- to polyetheretherketone- based composites: Investigation on the material of the energy director and the thickness of the coupling layer

2020 ◽  
Vol 54 (22) ◽  
pp. 3081-3098 ◽  
Author(s):  
Eirini Tsiangou ◽  
Sofia Teixeira de Freitas ◽  
Irene Fernandez Villegas ◽  
Rinze Benedictus
Keyword(s):  
Mechanical Performance ◽  
High Strength ◽  
Ultrasonic Welding ◽  
Thermoplastic Composite ◽  
Thermoset Composites ◽  
Excellent Candidate ◽  
The Matrix ◽  
Energy Director ◽  
Epoxy Systems ◽  
Composite Samples

Ultrasonic welding is a highly promising technique for joining thermoplastic to thermoset composites. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the thermoset composite ‘weldable’. A reliable bond is attained when miscible thermoplastic and thermoset materials are chosen. For welding carbon fibre/polyetheretherketone (PEEK) to thermoset composite samples, a PEEK film is not preferable due to its immiscibility with epoxy resins. On the other hand, polyetherimide is an excellent candidate, since it is known to be miscible to most epoxy systems at high temperatures and PEEK polymers. This study focusses on two main subjects; firstly, the nature of the material of the energy director, i.e. a flat thermoplastic film used to promote heat generation at the interface. In this case, the energy director can be either polyetherimide, as in the coupling layer or PEEK material, as in the matrix of the thermoplastic composite adherend. It was found that both materials can produce welds with similar mechanical performance. This study focusses secondly on the thickness of the coupling layer. Due to the high melting temperature of the PEEK matrix, a 60-µm-thick coupling layer was seemingly too thin to act as a thermal barrier for the epoxy resin for heating times long enough to produce fully welded joints. Such an issue was found to be overcome by increasing the thickness of the coupling layer to 250 µm, which resulted in high-strength welds.

scholarly journals Continuous ultrasonic welding of thermoplastic composites: Enhancing the weld uniformity by changing the energy director

2019 ◽  
Vol 54 (15) ◽  
pp. 2023-2035 ◽  
Author(s):  
Bram Jongbloed ◽  
Julie Teuwen ◽  
Genevieve Palardy ◽  
Irene Fernandez Villegas ◽  
Rinze Benedictus
Keyword(s):  
Thin Film ◽  
Heat Generation ◽  
High Speed ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Weld Strength ◽  
Good Contact ◽  
Energy Director ◽  
Welded Seam

Continuous ultrasonic welding is a high-speed joining method for thermoplastic composites. Currently, a thin film energy director is used to focus the heat generation at the interface. However, areas of intact energy director remain in the welded seam, which significantly lowers the weld strength, and result in a non-uniformly welded seam. To improve the weld uniformity of continuous ultrasonically welded joints, we changed to a more compliant energy director. A woven polymer mesh energy director was found to give a significant improvement in weld quality. The mesh was flattened in between the composite adherends during the welding process. This flattening promoted a good contact between the energy director and the adherends, fully wetting the adherend surfaces, resulting in a more uniformly welded seam without areas of intact energy director.

scholarly journals A Study on Through-the-Thickness Heating in Continuous Ultrasonic Welding of Thermoplastic Composites

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6620
Author(s):  
Bram C. P. Jongbloed ◽  
Julie J. E. Teuwen ◽  
Rinze Benedictus ◽  
Irene Fernandez Villegas
Keyword(s):  
Vibrational Energy ◽  
Continuous Process ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Squeeze Flow ◽  
Transfer Model ◽  
Welding Interface ◽  
Energy Director ◽  
Energy Share

Continuous ultrasonic welding is a promising technique for joining thermoplastic composites structures together. The aim of this study was to gain further insight into what causes higher through-the-thickness heating in continuous ultrasonic welding of thermoplastic composites as compared to the static process. Thermocouples were used to measure temperature evolutions at the welding interface and within the adherends. To understand the mechanisms causing the observed temperature behaviours, the results were compared to temperature measurements from an equivalent static welding process and to the predictions from a simplified heat transfer model. Despite the significantly higher temperatures measured at the welding interface for the continuous process, viscoelastic bulk heat generation and not thermal conduction from the interface was identified as the main cause of higher through-the-thickness heating in the top adherend. Interestingly the top adherend seemed to absorb most of the vibrational energy in the continuous process as opposed to a more balanced energy share between the top and bottom adherend in the static process. Finally, the higher temperatures at the welding interface in continuous ultrasonic welding were attributed to pre-heating of the energy director due to the vibrations being transmitted downstream of the sonotrode, to reduced squeeze-flow of energy director due to the larger adherend size, and to heat flux originating downstream as the welding process continues.

Ultrasonic welding of thermoplastics in the far-field

1989 ◽  
Vol 29 (23) ◽  
pp. 1699-1704 ◽  
Author(s):  
Avraham Benatar ◽  
Zhang Cheng
Keyword(s):  
Ultrasonic Welding ◽  
Far Field

Ultrasonic Welding of Glass Fiber Reinforced PP Thermoplastic Composites: An Investigation of the Outer Layer Orientation and the Fiber Volume Fraction

2020 ◽  
Vol 858 ◽  
pp. 3-13
Author(s):  
Murtada Abass A. Alrubaie
Keyword(s):  
Shear Strength ◽  
Glass Fiber ◽  
Outer Layer ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Fiber Volume ◽  
Energy Director ◽  
Welding Pressure

This paper presents an experimental study of the influence of the orientation of the outer layer of polypropeylene (PP) reinforced with E-glass fiber laminate (GF/PP) and the influence of the fiber volume fraction on the quality of the welded joint using an ultrasonic welding process. An orthogonal L 16 array (OA) design of experiment was conducted in this paper based on the Taguchi method to evaluate the effect of the orientation of the outer layer and the fiber volume fraction, on the welding process parameters; the welding energy, the amplitude of vibration, the welding pressure, the holding pressure and the holding time were considered in order to achieve a high weld quality. The experiments were carried out using a 15 kHz ultrasonic welding unit with a maximum supplied power of 4000-Watt. GF/PP laminates with fiber volume fraction of 36% and 46% were used in this paper, and the GF/PP laminates were either unidierctional or had a 90 degree outer layer orienation. A 0.127 mm thick polypropeylene film was used as a flat energy director (ED). The evaluation of the weld quality was measured by the apparent shear strength of the single lap welded joints, and by using laser shearography as a non-destructive inspection technique . The failure mechanism of the single lap joint was monitored, using a high speed digital imaging system. A combination of the highest selected level of welding energy, lowest level of amplitude, lowest level of welding pressure, and the lowest level of both hold time and hold pressure of a unidirectional GF/PP with the lowest fiber volume fraction, were found to achieve a higher apparent shear strength of the welded adherends, as compared with the apparent shear strength obtained with the presence of the flat energy director for the same level of factors. A confirmation experiment was conducted to measure the predicted apparent shear strength and compare it with the measured apparent shear strength from the test.

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