The influence of friction stir welding tool shape on quality of AZ31 Magnesium welding product

Magnesium is one type of material that can be used as a base metal in welding. Magnesium has superior properties, including low density, good ductility, medium strength and excellent corrosion resistance. Because of its properties, the metal is widely used, ranging from household goods to aircraft components. These base metals are categorised as mild when viewed from the specific gravity of magnesium (1.74 g/cm3 and 1.83 g/cm3). Welding is the process of merging two or more base metals which are merged at the contact surface with or without additives or fillers. Welding is divided into two main categories, Liquid and Solid-State Welding. Friction Stir Welding (FSW) is an example of Solid-State Welding (Non-Fusion Welding). FSW is a friction welding process that twists the tool by utilising heat energy and pressing without additives or fillers until the base metal is in a phase change. The welding process in this study used the cone and spiral shape with a tool rotation at 2000 rpm and a welding speed of 16 mm/min. The tests carried out are tensile and hardness testing. This study found that the tool shape, tool rotation, and welding speed significantly affect the mechanical properties of the welded AZ31 magnesium. The spiral shape will make the welding area wider. Although the cone shape will have a small area, the weld will look perfect with good tensile strength, while the hardness values for the two tool shapes are almost the same, but the cone shape is better.

Design of a contactless powered and piezoelectric-actuated tool for non-resonant low-frequency vibration-assisted machining of brittle-hard materials

Ultrasonic-assisted grinding (UAG) is the state-of-the-art process for machining of brittle-hard materials. In comparison to conventional processes, the main advantages lie in the reduction of tool wear and process forces. Such a vibration system is based on a resonant actuator and a power supply unit generating the alternating current. Both units are interconnected by a contactless energy transfer (CET) system. This system configuration shows one optimal working point at the resonant frequency with maximum amplitude, which is significantly depending on the tool shape. In this work, a piezo-activated tool system is designed to realize non-resonant low-frequency vibrations. Major emphasis is put on the thermal behavior of the piezo drive, particularly on the in-process heating depending on the working frequency. In addition, focus lays on the theoretical and numerical design of the radial operating transducer CET system for a previously set actuator design. As a result, this system configuration offers a fully variable adjustment of the amplitude from under 1 to over 50 μm at frequency range. Outside this range, higher amplitudes can be achieved for short periods to the detriment of the fatigue strength according to FKM.

The Influence of Tool Shape and Process Parameters on the Mechanical Properties of AW-3004 Aluminium Alloy Friction Stir Welded Joints

The purpose of the following study was to compare the effect of the shape of a tool on the joint and to obtain the values of Friction Stir Welding (FSW) parameters that provide the best possible joint quality. The material used was an aluminium alloy, EN AW-3004 (AlMn1Mg1). To the authors’ best knowledge, no investigations of this alloy during FSW have been presented earlier. Five butt joints were made with a self-developed, cylindrical, and tapered threaded tool with a rotational speed of 475 rpm. In order to compare the welding parameters, two more joints with a rotational speed of 475 rpm and seven joints with a welding speed of 300 mm/min with the use of a cylindrical threaded pin were performed. This involved a visual inspection as well as a tensile strength test of the welded joints. It was observed that the value of the material outflow for the joints made with the cylindrical threaded pin was higher than it was for the joints made with the tapered threaded pin. However, welding defects in the form of voids appeared in the joints made with the tapered threaded tool. The use of the cylindrical tool resulted in higher values for about 37% of mechanical properties compared with the highest result for the tapered threaded joint. As far as the parameters were concerned, it was concluded that most of the specimens were properly joined for a rotational speed of 475 rpm. In the joints made with a welding speed of 300 mm/min, the material was not stirred properly. The best joint quality was given for a rotational speed of 475 rpm as well as a variety of welding speed values between 150 and 475 mm/min.

Artificial neural network for modeling and investigating the effects of forming tool characteristics on the accuracy and formability of thin aluminum alloy blanks when using SPIF

Incremental Sheet Forming (ISF) has attracted attention due to its flexibility as far as its forming process and complexity in the deformation mode are concerned. Single Point Incremental Forming (SPIF) is one of the major types of ISF, which also constitutes the simplest type of ISF. If sufficient quality and accuracy without defects are desired, for the production of an ISF component, optimal parameters of the ISF process should be selected. In order to do that, an initial prediction of formability and geometric accuracy helps researchers select proper parameters when forming components using SPIF. In this process, selected parameters are tool materials and shapes. As evidenced by earlier studies, multiple forming tests with different process parameters have been conducted to experimentally explore such parameters when using SPIF. With regard to the range of these parameters, in the scope of this study, the influence of tool material, tool shape, tool-end corner radius, and tool surface roughness (Ra/Rz) were investigated experimentally on SPIF components: the studied factors include the formability and geometric accuracy of formed parts. In order to produce a well-established study, an appropriate modeling tool was needed. To this end, with the help of adopting the data collected from 108 components formed with the help of SPIF, Artificial Neural Network (ANN) was used to explore and determine proper materials and the geometry of forming tools: thus, ANN was applied to predict the formability and geometric accuracy as output. Process parameters were used as input data for the created ANN relying on actual values obtained from experimental components. In addition, an analytical equation was generated for each output based on the extracted weight and bias of the best network prediction. Compared to the experimental approach, analytical equations enable the researcher to estimate parameter values within a relatively short time and in a practicable way. Also, an estimate of Relative Importance (RI) of SPIF parameters (generated with the help of the partitioning weight method) concerning the expected output is also presented in the study. One of the key findings is that tool characteristics play an essential role in all predictions and fundamentally impact the final products.

User Expectations and Mental Models for Communicating Emotions through Compressive & Warm Affective Garment Actuation

Wearable haptic garments for communicating emotions have great potential in various applications, including supporting social interactions, improving immersive experiences in entertainment, or simply as a research tool. Shape-memory alloys (SMAs) are an emerging and interesting actuation scheme for affective haptic garments since they provide coupled warmth and compressive sensations in a single actuation---potentially acting as a proxy for human touch. However, SMAs are underutilized in current research and there are many unknowns regarding their design/use. The goal of this work is to map the design space for SMA-based garment-mediated emotional communication through warm, compressive actuation (termed 'warm touch'). Two online surveys were deployed to gather user expectations in using varying 'warm touch' parameters (body location, intensity, pattern) to communicate 7 distinct emotions. Further, we also investigated mental models used by participants during the haptic strategy selection process. The findings show 5 major categories of mental models, including representation of body sensations, replication of typical social touch strategies, metaphorical representation of emotions, symbolic representation of physical actions, and mimicry of objects or tasks; the frequency of use of each of these mental frameworks in relation to the selected 'warm touch' parameters in the communication of emotions are presented. These gathered insights can inform more intuitive and consistent haptic garment design approaches for emotional communication.

Nest substrate and tool shape significantly affect the mechanics and energy requirements of avian eggshell puncture

Some host species of avian obligate brood parasites reject parasitic eggs from their nest whereas others accept them, even though they recognize them as foreign. One hypothesis to explain this seemingly maladaptive behavior is that acceptors are unable to pierce and remove the parasitic eggshell. Previous studies reporting on the force and energy required to break brood parasites’ eggshells were typically static tests performed against hard substrate surfaces. Here, we considered host nest as a substrate to simulate this potentially critical aspect of the natural context for egg puncture while testing the energy required to break avian eggshells. Specifically, as a proof of concept, we punctured domestic chicken eggs under a series of conditions: varying tool shape (sharp vs. blunt), tool dynamics (static vs. dynamic), and the presence of natural bird nests (of three host species). The results show a complex set of statistically significant interactions between tool shapes, puncture dynamics, and nest substrates. Specifically, the energy required to break eggs was greater for the static tests than for the dynamic tests, but only when using a nest substrate and a blunt tool. In turn, in the static tests, the addition of a nest significantly increased energy requirements for both tool types, whereas during dynamic tests, the increase in energy associated with the nest presence was significant only when using the sharp tool. Characterizing the process of eggshell puncture in increasingly naturalistic contexts will help in understanding whether and how hosts of brood parasites evolve to reject foreign eggs.

Die equipment and tool for manufacturing sandwich flat ring parts with composites

The results of designing die equipment and special tool through separate die operations for manufacturing sandwich flat ring parts with the middle base metal layer and periphery elastic layers with increased composite thickness are shown. Efficient geometrical dimensions and a tool shape ensuring qualitative manufacturing parts mentioned and extension of technological potentialities of separating operations for their manufacturing, in particular, for design options with the increased thickness of periphery elastic composite layers are optimized experimentally.

Draught Requirements of Tillage Tines in Clay Soil under Indoor Soil Bin Conditions

Large tine (Tl) and sweep tine (Tw) were the different model tillage tines used for this research. The blades were used on clay soil in a soil bin of dimension 9.0 × 0.85 × 0.5m located in the Department of Agricultural Engineering of the Federal University of Technology, Akure, Nigeria. The clay soil used for the experiment was obtained from Agricultural Engineering Step B Farm. The objective of this study was to evaluate the draught requirements of the model tillage tools and to evaluate and model the parameters of the soil profile produced under different operating conditions. It involved testing and evaluation of tool shape, depth (12.5 -100mm) and rake angles (300, 450, and 900) and forward speed (0.17m/sec) on draught force. Soil profile patterns measured by a profilometer was analyzed using the following parameters – maximum Width of soil cut (Wfs), Ridge-to- Ridge Distance (RRD), furrow depth (df), height of ridge (Hr), maximum Width of Soil Throw (TDW) and tool width (w). Results showed that draught is directly proportional to the depth of the tine at a certain rake angle. The Tw had the least draught while Tl had the highest draught. Analysis of soil disturbance parameters revealed an increase in parameters with increasing cone index and depth of the tines. The study provides relevant data in the design of soil engaging tools and sustainable crop production. Keywords: Draught, Clay, Soil disturbance, Tillage, Tines.