Scientific Journal of Impact Factor(SJIF): 3.134
e-ISSN(O): 2348-4470 p-ISSN(P): 2348-6406
International Journal of Advance Engineering and Research Development Volume 2,Issue 5, May -2015
A Review on Ultrasonic Welding of Glass Fibre Reinforced Plastic Khyati H. Vyas 1 , Prof. Akash B. Pandey 2 , Prof. Paawan Panchal3 1
2
PG Fellow, Mechanical Engineering Dept., Merchant Engineering College, Dept. of Mech. Engg., Faculty of Tech. and Engg., M. S. University of Baroda,
[email protected] 3 Mechanical Engineering Dept., Merchant Engineering College,
Abstract: The “composite material” is composed of a discrete reinforcement & distributed in a continuous phase
of matrix. In Glass Fibre reinforced plastic (GFRP) composite, plastic is used as matrix which form network with glass fibre. Glass fibre composites are strong and stiff being light in weight increases strength to weight and stiffness to weight ratios. Plastic composites can joined by mechanical fastening, adhesive bonding and welding. Mechanical fastening, adhesive bonding combined with pre-treatment and welding , therefore, have been applied for joining. Ultrasonic welding has received significant attention during past few years due to their suitable applications in comparison to conventional fusion welding techniques. Strength of ultrasonically welded GFRP depends on process parameters like pressure, weld time, thickness ratio, and amplitude. This paper presents an overview of ultrasonic welding process, joining of GFRP, and process parameters. Keywords: Ultrasonic welding, GFRP, composite, process parameter, strength.
I. INTRODUCTION A composite material is a material system composed of two or more physically distinct phases whose combination produces aggregate properties that differs fro m those of its constituents [I]. The technological and commercial interest in composite materials derives from the fact that their properties are not just different fro m their co mponents but are often far superior [I]. In Glass Fibre reinforced plastic (GFRP) co mposite, plastic is used as matrix which form network with glass fibre. Glass fibre co mposites are strong and stiff being light in weight increases strength to weight and stiffness to weight ratios. Joints are necessary when part integration is not possible because of co mplex geo me try and high costs. The effect iveness of the joining operation can have a large influence on the application of any composite material[1]. In general, jo ining of composites can be categorized into mechanical fastening, adhesive bonding, solvent bonding, c o-consolidation, and fusion bonding or welding. Fusion bonding or welding has great potential for the join ing, assembly, and repair of GFRP composite components and also offers many advantages over other joining techniques[2].
II. ULTRASONIC WELDING Figure.1 shows the schematic d iagram of Ultrasonic Weld ing machine. The setup consists of a power supply, a p iezoelectric or magnetostrictive transducer, a booster, a horn, a substrate, and a support base or anvil. First of all, the power supply will convert low voltage electricity to high frequency electrical energy and then the converter converts electrical energy to mechanical v ibratory energy. Next , the booster adjusts the amplitude of the vibrat ions and transmits them to the horn where it transmits vibratory energy to the parts. The pressure is applied on the substrate through the horn. With the help of proper design of fixtures, ult rasonic welding can be used in jo ining of large parts . The applicat ion of u ltrasonic welding is extensive in many industrial branches including electrical, co mputers, energy, medical, aerospace, automotive, and packaging etc. Especially aerospace industry employs this technique to joint light weight thermoplastic matrix co mposite materials. Ultrasonic weld ing is a versatile and powerful joining technique in the microelectronic packag ing industry because of the low temperature, high yield rate and flexibility of the process. The main advantages of ultrasonic welding include, absence of liquid–solid t ransformat ions, low energy consumption, no at mosphere control required, works fo r d issimilar metals, low temperature allo ws embedding of electronics, such as sensors and actuators and most importantly, it is environ mental friendly and very fast[3]. Ult rasonic weld ing is a fast and clean process, and usually produces welds that are relatively free of flash.
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International Journal of Advance Engineer ing and Research Development (IJAERD) Volume 2,Issue 5, May -2015, e-ISSN: 2348 - 4470 , print-ISSN:2348-6406
Figure.1 : Schematic diagram of ultrasonic welding machine [4]. III. LITERATURE S URVEY A literature review surveys scholarly articles, books, dissertations, conference proceedings and other resources which are relevant to a particular issue, area of research, or theory and provides context for a d issertation by identifying past resea rch. Various research papers were reviewed regarding my project "PARAM ETRIC A NA LYSIS OF COM POSITE USING ULTRASONIC W ELDING" as follows. Shakil et.al[5] investigated effect of ultrasonic parameters on micro structure and mechanical properties of dissimilar joints. The objective of the work was to optimize u ltrasonic spot welding parameters for joining 3003 Alu minu m alloy with 304 Stainless steel. The ultrasonic vibration amp litude was kept around 58 µm with constant maximu m power of 2.4 MPa. The weld ing energy was varied between 75 and 200 J under different clamp ing pressures i.e. 30, 40, 50 and 60 psi. Lap shear tensile test was performed for each weld to evaluate jo int strength. For micro structural examination, samples were etched at room temperature using Weck solution (100 ml water, 4 % potassium permanganate and 1 % sodiu m hydro xide) and images were taken by Oly mpus GX 51 optical microscope. Similar results were observed for clamp ing pressure 40 and 60 psi i.e. bond strength increased with energy up to 125 J and then start decreased. For 30 psi clamp ing pressure strength fluctuated upto 150 J energy and then increased with increase in energy. It was concluded that with the increase of clamp ing pressure, almost same weld strength was achieved at lower energy values in relatively short time. For 60 psi pressure, the strength decreases even at higher energies. This was due to the fact that in USW the h igher pressure results increased heat generation due to high sliding resistance. To investigate the relationship between physical weld attributes and weld performances, optical microscopy and hardness measurements were performed on the cross -section surface of selected samples welded by 40 psi clamp ing pressure and at various welding energy values. Fro m the micrographs it was seen that there exists gap at the interface fo r lower energy of 75 J. Gaps were reduced with increase in weld energy. It was clea rly observed that the imprints of anvil and sonotrode intensify with increasing weld ing energy which results material deformat ion due to excessive energy input. Lap shear tensile test revealed that the weld produced with lo w energy values of 75 and 100 J failed at s mall tensile load due to the cold worked microstructure which are classified as ‘‘under’’ weld. The weld specimen prepared with energy 125 and 150 J showed the maximu m tensile load and is rated as ‘‘good’’ weld. The weld produced with h igh energ y 175 and 200 J shows the lower strength due to the softening and thinning caused by the recrystallization at the interface and it is classified as ‘‘over’’ weld. Villegas[6] investigated on optimu m process parameters in ultrasonic welding of thermoplastic co mposites with flat energy directors. He described the ability to relate weld strength to the process parameters namely dissipated power and displacement of sonotrode in ultrasonic welding of thermoplastic composite parts with flat energy directors. The material used for the study was Carbon Fiber reinforced polyetherimide. M icrographic cross -sections in the centre of the overlap were used to assess the changes at the welding interface and in the co mposite adherends at different stages of the welding pro cess. Likewise, fractography was used to evaluate the main failure modes in the d ifferent weld ing conditions. The single lap @IJAERD-2015, All rights Reserved
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International Journal of Advance Engineer ing and Research Development (IJAERD) Volume 2,Issue 5, May -2015, e-ISSN: 2348 - 4470 , print-ISSN:2348-6406 welded samples were mechanically tested to find lap shear strength. The dissipated power and the displacement of the sonotrode during the vibration phase of the welding process were obtained as feedback from the ultrasonic welder. Three different combinations of welding force and vibration amp litude were analyzed, (i) 300 N and 86.2 µm, used as a reference; (ii) 300 N and 51.6 µm, lower amp litude than the reference; and (iii) 1500 N and 86.2 µm, higher force than the reference. Maximu m weld strength is achieved within stage 4 of the welding process, which therefore constitutes a target for optimu m weld ing conditions. The selection of the other two welding parameters, i.e. welding force and vibration amp litude, primarily affects the power required fo r weld ing, the weld ing time and the extent of the heat affected zone in the substrates. High for ce and high amplitude combinations decrease the welding time and the extent of the heat affected zone, but at a cost of higher dissipated power. No significant effect of the force and the amp litude on the weld strength wa s observed for the material and the parameter ranges investigated in this work. Rani and Rudramoorthy[7] investigated on dynamic perfo rmance of u ltrasonic horn profiles used in plastic weld ing. Ultrasonic horns are tuned components designed to vibrate in a longitudinal mode at u ltrasonic frequencies. Different horn profiles for ultrasonic welding of thermoplastics were characterized in terms of displacement amp litude and von -Mises stresses using modal and harmonic analysis. Five different horns were fabricated fro m alu minum and tuned to operating frequency. ABS plastic samples were welded using different p rofile horns. Horns are designed to have high amplitude/ velocity at the tip for weld ing. The dynamic performance of each horn was correlated to the weld interface temperature and to the strength of the welded joint. The horn design was optimized based on the results of the dynamic analysis using ANSYS and experimental data. Stepped, Catenoidal, Cylindrical, Gaussian and Bezier horn profiles were considered for the study. For a fair co mparison of all the horns, the diameters at upper and lower end were kept at 68 mm and 35 mm respectively. Different horn profiles were generated using Pro-E (version V) and Unigraphics (version 7.5). The horn profiles were then imported to ANSYS (version 12) to perform the modal and harmonic analys is. To obtain the natural frequency close to the mach ine frequency (20 kHz ± 500 Hz) the horn length was adjusted to 136 mm for the Gaussian and Stepped horn by trial and error. The horn length for Cylindrical, Bezier and Catenoidal profile was 130 mm. It was observed that the displacement for the Bezier profile horn was maximu m followed by the Stepped horn and the Catenoidal horn. The weld strength increased with a corresponding increase in weld interface temperature. High interface temperatures resulted in better melting and bonding led to stronger welded joints. The highest weld strength 3.65 MPa obtained for specimens welded by Bezier horn. To validate the efficiency of the Bezier horn; far field welding of High Density Polyethylene (HDPE) samp les was carried out. The Bezier horn was able to weld HDPE specimens up to 50 mm length where as stepped horn and the Catenoidal horn welded specimens up to 45 mm, and Gaussian horn welded specimens up to 30 mm length and the cylindrical horn did not weld any HDPE specimen. The specimens welded by Bezier horn were three times stronger than the specimens welded by the Gaussian horn and 1.5 t imes stronger than that of the Catenoidal horn. Amend et.al[8] conducted experimental investigation on Laser based hot melt bo nding of thermosetting GFRP. According to current state of art the joining of thermosetting composite to thermoplastic is limited by available join ing techniques. He performed experiments to join two thermosetting GFRP co mposites with a thermoplastic interlayer. Polycarbonate (PC) and Polyamide (PA) of varying carbon black contents (0.01; 1; 2; 20 wt.%) were used as thermoplastic interlayer. GFRP samples were made up of studs and micro roughness surface structure. All joined specimens were analyzed by tensile shear strength. Also climate tests were performed to investigate long term durab ility of joints. Carbon black of about 1 to 2 wt.% resulted maximu m tensile shear strength of 8 MPa for fabricated joints of GFRP and polyamide. Lo wer or higher weight conte nts lead to a decrease of tensile shear strength. Tensile shear strength is also influenced by glass fiber content in thermoplastics. The surface quality of GFRP affects the tensile shear strength. Surface having micro roughness has higher tensile shear st rength than surface with studs because of an additional mechanical interlocking between the joining partners and better loading condition through adaption of the bending stiffness of both materials. Tensile strength of joints is reduced after climate te st. A reduction of 49-59% in tensile shear strength of unreinforced thermoplastic joint is obtained. Whereas decrease of tensile shear strength for glass fiber reinforced thermop lastic is only about 38%. The maximu m tensile shear strength for GFRP GFRP joint connection is about 13.1 MPa. Anahi et.al[3] reviewed on weld ing technologies for thermoplastic co mposites in aerospace applications. Join ing plays an important role in manufacturing o f co mposite structures in marine, auto motive, and aerospace industry. He examined different welding techniques such as ultrasonic welding, induction weld ing, micro wave welding, resistance welding, hot plate weld ing, and laser welding, for joining of thermoplastic co mposite laminates devised for structural aerospace applications. Fusion bonding methods present a huge potential for volu me intensive applications in which short processing cycles are necessary. These bonding processes offer additional advantages including reduced surface preparation requirements, reprocessing, recyclability, and improved integrity/ durability. Ultrasonic welding is used in many branches like electrical, @IJAERD-2015, All rights Reserved
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International Journal of Advance Engineer ing and Research Development (IJAERD) Volume 2,Issue 5, May -2015, e-ISSN: 2348 - 4470 , print-ISSN:2348-6406 computer, auto motive, med icine, packaging, and in part icular in aerospace application to jo in light weight thermoplastic matrix co mposite materials. Investigations comparing resistance and induc tion welding showed that for equivalent heating conditions, induction welding displayed higher shear strength. Microwave heating is still under development stage and there are no currently reported industrial applications. One disadvantage of microwave ene rgy only homogeneous material heating is possible with simple geo metries. Resistance weld ing proved to be one of the promising techniques in aerospace applications because of its faster welding and less amount of material requirement and can be applied to lager structures. Marius and Fleser[9] optimized the parameters of ult rasonic welding for co mposite material fo r increasing weld strength using Design Of Experiments. In the paper, weld ing parameters, like welding t ime, weld ing pressure and amplitude of the vibration were taken into account during the realization of ult rasonic welded jo ints of Al/20%SiC co mposite material under disks form, whose thickness was 1 mm. An optimization of process parameter was done using 2 k full factorial experiment method. Range of pressure selected was 1.4 and 1.7 bar, weld t ime 1.2 and 2 sec, and amplitude 70 and 85%. The optimal parameters settings to achieve the maximu m strength of the joint is: weld ing pressure of 1.4 bar; welding time of 1.2 sec.; and, amp litude of the sonotrode of 85%. The optimal parameters settings for min imize the strength of the joint is: welding pressure of 1.4 bar; welding time of 2 sec; and, amplitude of the sonotrode of 85%. Rashli et.al[10] reviewed on the process of ultrasonic welding thermoplastic co mposites. He described ult rasonic welding as one of the most common methods of the welding techniques for join ing thermoplastics. Ultrasonic weld ing is the fastest of all the techniques, can weld within one second. There are five main parameters of variab les in general ultrasonic weld ing wh ich are weld pressure, weld time, hold time, frequency and amplitude. He concluded that increase in weld pressure increased weld quality upto a certain point. Too low pressure resulted into incomplete melt flow while too high pressure gave misalignment in flow direction resulting into bad quality of weld. An increase in weld p ressure reduced weld time at constant amp litude. Increase in weld t ime led to better strength where as if welding time increases critical weld t ime might damage part and bring extensive flash. Hold time is defined as the delay time after the ultrasonic welder is turned off before the clamping force is released which allows the parts for cooling. Hold time does not really affect the welding performance. Welding characteristics can be improved by using higher frequency because of the larger vibration loss of plastic materials. He found that difficulties in welding thin layers of d issimilar material can be solved by using high frequency vibration and pressure to input energy into the joint area. The weld strength was increased with increasing amp litude with no significant changes in other criteria. High frequency, complex v ibration and two vibration system welding methods are most suited for plastic materials. Ahmed et.al[11] rev iewed on the process of induction welding of thermop lastic composites. The main focus was put on the types of heat generation mechanisms during the induction heating process and the parameters that govern the welding process such as frequency, power, pressure, residence time as well as the quality of the weld. For heating applications on composites three types of coils were considered: single turn coil, solenoid coil, and pancake coil. Single turn coil was used for circular areas for heating wh ile solenoid coil was used to heat larger circular areas where as pancake coil was used for heating flat areas. Three categories of heating mechanisms were identified, namely Joule loss, junction heating and hysteresis loss. The mechanis ms differs in the way the heating takes place within work piece. He confirmed through experimentation that with increase in frequency at desired temperature decreases time to heat co mposite laminate drastically. There was several issues, most notably the edge effect and the local heating effect, that prevent embracing induction weld ing on a large scale. Addressing these and other important issues remains as an incentive for further development of the induction welding method. Tsujino et.al[12] studied on Ultrasonic plastic weld ing using fundamental and higher resonance frequency vibrations simu ltaneously. Welding characteristics of ultrasonic welding is imp roved by using higher frequency, due to the larger vibration loss of plastic materials. Vib ration characteristics of a 26 kHz v ibration system clamped at a nodal flange part were measured by a laser Doppler vibro meter. The vib ration system consists of a bolt -clamped Langevin type PZT transducer and a stepped conical horn with a supporting flange at a nodal position. The welding tip part v ibrates at fundamental and also at several higher resonance frequencies up to 95 kHz whose vibration velocities are over one -third that of the fundamental frequency. Welding characteristics of 1.0-mm-th ick polypropylene sheets were measured in the cases the vibration system are driven under co mbined driv ing voltages of fundamental and h igher resonance frequencies. The welded areas by fundamental and two higher frequencies were about three to four times that of the case where only the fundamental frequency is driven. The weld ing characteristics of ultrasonic plastic welding were improved significantly by driving higher resonance frequencies simultaneously. @IJAERD-2015, All rights Reserved
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International Journal of Advance Engineer ing and Research Development (IJAERD) Volume 2,Issue 5, May -2015, e-ISSN: 2348 - 4470 , print-ISSN:2348-6406 IV. RES EARCH GAP Fro m the literature survey, it was found that hardly any attempt was made to jo in glass fiber reinforced thermosetting plastic using welding techniques because thermosetting polymers cannot be heated once it is cured. Therefore, an investigation on effect of joining g lass fiber reinforced thermosetting plastic co mposite w ith thermoplastic as intermed iate layer using ultrasonic weld ing technique can be carried. V. OBJ ECTIVES AND SCOPE
To investigate the effect of ultrasonically transferred heat energy on glass fiber rein forced thermosetting material for weld ing. To study the ultrasonic weld ing of glass fiber reinforced thermosetting material with intermed iate thermoplastic. To analyze the effect of u ltrasonic welding process parameters on weld strength. Apply a MCDM technique for selecting most suitable welding parameters fo r given thickness of material. REFERENCES:
[1] T.J. Ahmed, D. Stavrov, H.E.N. Bersee, A. Beukers, "Induction welding of thermoplastic composites —an overview", Co mposites: Part A 37 (2006) 1638–1651 [2] Ali Yousefpour, Mehdi Hojjati and Jean -Pierre Immarigeon," Fusion Bonding/Welding of Thermoplastic Co mposites" Journal of THERMOPLASTIC COMPOSITE MATERIALS, Vo l. 17—July 2004 [3] Anahi Pereira da Costa, Eds on Cocchieri B otelho, Michelle Leali Costa, Nilson Ei ji Narita, José Ricardo Tarpani ," A Review of Welding Technologies for Thermoplastic Co mposites in Aerospace Applications" ,. Manag., São José dos Campos, Vol.4, No 3, pp. 255-265, Ju l.-Sep., 2012 [4] Irene Fernandez Villegas, Lars Moser, Ali Yousefpour, Peter Mi tschang and Haral d EN Bersee ," Process and performance evaluation of ult rasonic, induction and resistance welding o f advanced thermoplastic co mposites. ",Journal of Thermoplastic Co mposite Materials 2013 26: 1007, 30 August 2012 [5] M. Shakil, N.H. Tari q, M. Ahmad, M.A. Choudhary, J.I. Akhter, S.S. B abu," Effect of u ltrasonic weld ing parameters on microstructure and mechanical p roperties of dissimilar jo ints", Materials and Design 55 (2014) 263– 273 [6] Irene Fernandez Villegas ," Strength development versus process data in ultrasonic welding of thermoplastic co mposites with flat energy directors and its application to the definition of optimu m processing parameters", Composites: Part A 65 (2014) 27– 37 [7] M. Roopa Rani , R. Rudramoorthy, "Co mputational modeling and experimental studies of the dynamic performance of ultrasonic horn profiles used in plastic welding", Ultrasonics 53 (2013) 763– 772 [8] P. Amend, B. Pillach, T. Frick, M. Schmi dt," Laser-Based Hot-Melt Bonding of Thermosetting GFRP" , Physics Procedia 39 ( 2012 ) 147 – 153 [9] Marius Pop-Cali manu, Trai an Fleser," The increasing of weld strength by parameters optimizat ion of ultrasonic weld ing for co mposite material based on aluminu m using design of experiments.", 23. - 25. 10. 2012, Brno, Czech Republic, EU [10] Rashi qah Rashli, El mi Abu B akar, Shahrul Kamaruddi n, Abd Rahi m Othman," A Rev iew of Ultrasonic Welding of Thermoplastic Co mposites", Caspian Journal of Applied Sciences Research, 2(3), pp. 01 -16, 2013 [11] T.J. Ahmed, D. Stavrov, H.E.N. Bersee, A. Beukers, "Induction welding of thermop lastic composites —an overview", Co mposites: Part A 37 (2006) 1638–1651 [12] Jiromaru Tsujino, Misugi Hongoh, Ryok o Tanaka, Rie Onoguchi, Tetsugi Ueok a, "Ultrasonic plastic welding using fundamental and higher resonance frequencies", Ultrasonics 40 (2002) 375–37 BOOK: [I] Fundamentals of Modern Manufacturing, 4th Edit ion by Mikell P. Groover.
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