The paper aims to report researches in microbonding process of composite magnetic materials using as thermal source the heat produced in base materials by the conversion of the electromagnetic waves with high frequency into thermal energy. This technology can be applied by targeting the base materials with microwaves and taking into account that composite magnetic materials based on ferrites, present good absorbance and conversion properties of the microwaves into heat. For experimental research, the base materials were sintered sampled of raw products obtained from stoichiometric mixtures of 6Fe2O3 + BaCO3. The raw products were obtained by milling and alloying processes using planetary ball mills. The milling and alloying processes have been perfomed in dry environement for homogeneous mixtures and wet environment for mixtures obtained using mechanical alloying. In terms of eutectic alloys used for microbonding, there have been used lead free Sn96,5%+Ag3%+Cu0,5% with melting point around 2170 C. The microbonding process have been perfomed in two steps: first step was focused on prepairing the base materials by cleaning and deposition of eutectic alloys on their surfaces; the second step was the heating of the base materials in microwave field. A microwave generator with adjustable input power from 0 W to 6000 W with a WR340 waveguide have been used as thermal sources. The researches have shown that the base materials were bonded using less than 10 % of microwave power and the eutectic alloys reached the melting temperature în less than 3 seconds when the magnetron was set to full power. A matching load impedance automatic tuner up to 6000 W have been used for increasing the level of absorbed power from nicrowave generator to samples and decreasing the level of rejected power from composite magnetic material to microwave generator. The temperature have been measured using IR pyrometers with range measurement between 0 and 7000 C. The process can be succesfully applied to a large scale for small parts of electrical engines with permanent cermic magnets.
Research conducted aimed to compare the hybrid ultrasonic-thermal cutting technology with the classic thermal cutting one. The experimental program was carried out on the ISIM designed hybrid equipment, operating at a frequency of 35 KHz, with a cutting geometry of the ultrasonic horn - sonotrode and the thermal anvil designed specifically for the task at hand; the first phase of the experimental program was developed on the thermal cutting module, the second one was performed on the US-thermal hybrid module, both modules being part of the hybrid cutting equipment designed and patented by ISIM Timisoara. The research performed in this present paper, intends to highlight the benefits of the hybrid cutting technology when compared to classical thermal cutting, in order to process two types of materials with different specifications and dimensions. After visually inspection cut materials have been then compared with automotive seatbelt quality standard IATF - International Automotive Task Force 16949. Experiments highlighted that hybrid ultrasonic-thermal cutting process has a significant influence on the quality of processed materials when compared to classic thermal cutting process, which in some cases makes the materials unsuitable for use in the automotive industry. The paper further presents two types of technology data sets suitable for 2 types of materials and up to automotive industry requirements.
Fast development of Sustainability and Circular Economy concepts has been materialized in European Parliament Directive no 2019/904. This Directive requires to reduce the consumption of plastic material for the manufacture of disposable packaging. In spite of the aggressive campaign against plastic materials usage, there are huge advantages which must be considered before replacing them by other alternative materials. Downsizing, Lightweighting and Downgauging technics are employed from early stage in designing new products made by plastic materials. Product recyclability features and recycled materials usage for products manufacturing need also to be assessed during the design and testing phase. This article proposes ultrasonic welding as an alternative technology for manufacturing the hollow polypropylene balls. With the traditional technology, the manufacturing of these balls results in an uneven wall thicknesses and a large technological runner of material that needs to be grinded and reintroduced into the injection equipment and this involves high consumption of raw material and energy. The proposed method of manufacturing these hollow balls consists in forming the ball from two ball halves joined together by ultrasonic welding. This process will result in significant savings in raw material and energy. As a case study, the manufacturing of deo roll balls have been considered. Several experimental researches have been made using ultrasonic welding at frequencies of 20 kHz and 35 kHz. Significant improvements on the capabilities of the ball external diameters have been recorded by ultrasonic welding using the frequency of 35 kHz. Further testing and comparative study of mechanical properties must be considered in order to define the best process parameters for hollow plastic balls manufacturing by Ultrasonic Welding.
The paper aims to report preliminary researches towards to development of new hybrid welding system by coupling a microwave beam with a TIG torch. The main research was focused on the designing of hybrid system as well as to establish the heating/welding mechanism by coupling two different thermal sources. Therefore, a specific welding chamber was designed taking into consideration the limitations provided by microwave waveguide technical specs, geometrical shape and dimensions of the TIG torch as well as the temperature monitoring during welding process and video surveillance for data recording. A microwave generator with adjustable power from 0 to 1250 W was coupled with a TIG torch and welding power source in order to establish the main parameters for hybrid system. The preliminary researches reported that the MW-TIG hybrid welding could be applied to eutectic joining of materials using low power (up to 600 W) injected from microwave generator as well as low welding current (up to 20 A). The flow of shielding gas have been established initially to 2 l/m. The research related to stabilization of MW-WIG plasma arc have been studied by increasing the flow of shielding gas up to 10 l/m. The results have shown that the microwave generator and TIG torch can be coupled to obtain hybrid-welding process without any matching tuning devices but with risks for damaging the microwave generator. Further researches will be done in order to design auxiliary devices to optimize the hybrid-welding process and to avoid any unwanted plasma arc discharge from welded base materials to microwave generator. In terms of temperature monitoring, an infrared pyrometer has been used. The IR pyrometer was targeted to the base materials in order to be able to measure their temperature without any influences from plasma arc. The results obtained have shown a stable plasma at average microwave power around 400 W even without any TIG current.
The aim of the current study is to perform a failure analysis on specimens extracted from 4 mm sheets of AZ31B, according to ASTM 4377G and 3 mm sheets of Cu99 alloys according to SR EN 1652:2000, that were joined together using FSW and FSW-IG processes. In order to promote the suitability and advantages of implementing FSW-IG processes in the automotive and aerospace industry, the papers authors performed destructive testing on the samples extracted, namely tensile strength test, following with topography analysis using scanning electron microscopy – SEM, combined with energy dispersive spectroscopy EDS, micro-hardness tests and fractography investigations. Results highlighted a considerable improvement in the ultimate tensile strength of the welded joint, a higher degree of deformability of the welded joint in the case of FSW – IG, compared to classical FSW; while maintaining the same process conditions and parameters. Experimental data is in accordant with automotive and aerospace imposed compliances, thus presented and discussed in the following scientific article.
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