Annals of “Dunarea de Jos” University of Galati. Fascicle XII, Welding Equipment and Technology

4D Printing of Commercial Based Conductive Polylactic Acid: Strength and Resistance Properties

A. Aram, M. Faigenblat, A. Ulanov, D. Richkov, M. Ayal, D. Ashkenazi, A. Stern — Thu, 28 Dec 2023 00:00:00 +0200

Four-dimensional (4D) printing technology is an innovative concept integrating conventional 3D printing additive manufacturing (AM) and smart materials programed to change properties or shape over time in response to environmental stimuli. This study aims to characterize the strength and electrical resistance of a commercial electrically conductive polylactic acid (PLA) with carbon black (CB) particles printed by fused filament fabrication (FFF) technique to evaluate the development feasibility of two sensor prototypes: (1) a load-cell sensor, and (2) a temperature sensor. Experiments were performed to study the orientation and raster angle–dependent mechanical and electrical performance of a PLA-CB conductive polymer manufactured by AM-FFF technology. A good agreement was observed between the data received from the manufacturer and the experimental density of the conductive AM-FFF PLA-CB three-point bending samples. The mechanical properties of 3D-printed PLA-CB were characterized based on three-point bending flexural test. Two build orientations (flat and upright) and three raster patterns (0°/90°, +45°/-45°, and concentric) were printed to check the optimal mechanical properties for electrical conductivity; six samples were printed for each one of the six configurations. The three-point bending flexural test results of the examined 36 specimens demonstrated that the samples printed in the concentric and +45°/-45° raster patterns exhibit the best mechanical properties, with the highest flexural strength and flexural modulus of elasticity in the flat orientation. Nevertheless, the concentric pattern has an advantage over the +45°/-45° pattern due to higher density and homogeneity. To examine the electrical resistance of the PLA-CB material another 12 specimens were printed and divided into four groups, each with different lengths. The electrical intrinsic resistivity was calculated from the geometry of the specimens and the measured resistance, with an average value of 13.2 [Ω·cm]. To check the production feasibility of a load-cell sensor prototype the effect of load on electrical conductivity was examined, however no effect of load on resistance was discovered. To prove the production feasibility of a sensor prototype for temperature measurements a preliminary device was designed and the effect of increasing and decreasing the temperature between 24 and 42°C on electrical resistance was examined. Based on the experimental results a calibration function was built linking between the temperature and the material’s resistance.

Recent Advances in Adhesive Bonding of 3D-Printed Parts and Methods to Increase their Mechanical Performance

Thu, 28 Dec 2023 00:00:00 +0200

The use of additive manufacturing (AM) has revolutionized the production of polymer-based materials, offering a wide range of design possibilities and geometric complexity. However, due to the limitations of 3D printers to produce large parts, the parts often must be printed in several separate components and further joined together to obtain the final 3D-printed part. 3D printing can be used to produce only the most complex parts, which can be further combined with simple, non-printed parts from other materials to make the final product. One way to join 3D-printed part is an adhesive-bonded method. This paper focuses on the recent advances in adhesive bonding techniques for 3D-printed parts and explores various methods to enhance their mechanical performance. The benefits and limitations of each technique were discussed, and highlighted promising paths for future research. Finally, this paper provides a comprehensive overview of the current strategies to improve the mechanical performance of adhesive joints with AM-based adherents, offering guidance for the design and fabrication of high-performance structures in a range of applications. It was concluded that the configuration of the bonding area represents an essential parameter that directly influences the bonding strength and overall structural integrity of AM adhesive joints, and that the implementation of customized joint geometries can lead to a substantial enhancement in the joint strength of 3D-printed parts. The incorporation of reinforcing materials, optimization of the printing parameters of adherents, pre and post-treatment methods show potential in enhancing the bonding strength of the 3D-printed joints. The synergistic integration of these cutting-edge technologies can yield mutual advantages that complement each other, ultimately resulting in an enhanced overall performance for AM parts.

Edge Detection and Defects Checking of Binder Clip and Welding Joint using a Python-Based Algorithm: Applications in Quality Inspection

S. Senthil Murugan, P. Sathiya, K. Hariharan, J. McJone, K. K. Nithiyanantham — Fri, 15 Dec 2023 00:00:00 +0200

Machine vision is a computer vision system that enables a computer to work on image-based inspection and analysis for different applications. In this computer vision, a camera and sensor were used to view an image for its analysis with the help of some sort of algorithms, then processed to infer the image-based data. Machine vision systems along with Python programs can be used for many interdisciplinary applications like weld inspection, online monitoring in manufacturing auto components etc. In this study, the “Edge detection python algorithm” was developed and run through “Google Colab” notebook to inspect the edges and the boundaries of samples like faying surface-modified friction welded dissimilar joints and a binder clip (paper clamp) to check any defects or cracks and straightness etc. With the help of this Python algorithm, the edge detection was done by Sobel, Scharr, and Prewit operators. An input image of the weld joint and the binder clip were converted into Otsu’s binary threshold image. The matrix vision camera and the CMOS sensor were used in the machine vision set-up to take the images. This written algorithm is helpful to trace the edges of any kind of solids components. The edges of the binder clips and the weld joint/zone were detected. The binder clips were inspected under two different cases namely the clip in folding condition (Case I) and the binder clip in unfolding condition (Case II). The results showed a defect that was identified in the weld zone and no bending was in the binder clips. This kind of study is useful in manufacturing industries for quality inspection purposes with a new machine vision set up for online inspection of fabricated components like nuts and bolts etc.

S-FMECA Based Collaborative Design Proposal for Additive Manufacturing Methodology

N. Chtioui, R. Gaha, S. Chatti, A. Benamara — Thu, 28 Dec 2023 00:00:00 +0200

In the current context, the sustainable development, eco-design and eco-manufacturing concepts are being developed in research laboratories, and further being integrated gradually into manufacturing industries. Hence, the needed information for eco-design is scattered throughout the product life cycle and is not centralized; especially when designing for Additive Manufacturing. This paper aims to develop a collaborative eco-design methodology by using eco-design tools in different design stages and, finally, to contribute to tackling this issue. Either in the early design stage or in the detailed on, the designer will be supported to make sustainable, conscious decisions. The proposed methodology based on the sustainable-failure modes, effects, and criticality analysis (S-FMECA) eco-designing tool allows the communication with computer-aided design (CAD), computer-aided manufacturing (CAM), life cycle assessment (LCA), topology optimization (TO) and product life cycle management (PLM) software in order to assist the designer to make green-conscious decisions.

Simulation Study of Critical Aspects of MIAB Welding for Analysis of Potential Factors Governing the Performance of Weld Formation

C. Mukti, S. Arungalai Vendan — Thu, 28 Dec 2023 00:00:00 +0200

Magnetically Impelled Arc Butt (MIAB) welding, is a solid-state welding technique. The magnetic system of this technique is pivotal for the generation of the Lorentz force, which impels an arc to rotate along the periphery of the weld tubes and thus facilitates the heating of faying surfaces. The magnetic arrangement and the arc dynamics significantly impact the effectiveness of the welding process, eventually dictating the efficiency. This study case investigates the impact of the magnetic arrangement on the arc rotation and possible factors that cause irregularities in the (MIAB) welding through COMSOL simulation. The COMSOL simulation has served as a powerful tool to comprehensively analyse various arc dynamics and magnetic systems and extrapolate the observations to analyse the arc dynamics and magnetic systems involved in MIAB welding. By employing simulation studies, the research aims to unravel critical insights for an efficient design of the MIAB welding system. This work includes a study of the effect of magnetic forces on arc dynamics using various models and attempts to develop an analogy to the MIAB welding process. This is further utilized to explain the process variations in the form of arc displacement, electric potential distribution, and the possibility of self-demagnetization of AlNiCo magnets. Thus, it provides a foundation for advancing the technological aspects of MIAB welding to overcome the limitations and irregularities. This research is instrumental in enhancing the understanding of magnetic interactions involved in the MIAB process, which can further pave the way for improved welding machine designs and consequently, enable research on these lines that can help in establishing an optimized parametric window.

A Synthetic Approach to Cold Presure Welding on Cogged Surfaces

B. Georgescu, G. Simion — Fri, 29 Dec 2023 00:00:00 +0200

Pressure welding on cogged surfaces represents a new technological variant of the cold welding. The components that are made from a material with higher plasticity (aluminium, lead etc.), having flat surfaces, are pressed on or between the harder material components (copper, brass, carbon/stainless steel, titanium, etc.) that have cogged surfaces. The main particularity of this technique is to achieve an appropriate joint by deforming only the component with higher plasticity. Due to the low degree of deformation needed, reduced pressure forces are applied in comparison with the classical cold pressure welding. The welding in isolated catching nodes is achieved by gripping, while the aluminium is gliding on the flanks of the teeth. The tensile strength of the joint is relatively low reaching up to 10% of the aluminium part, but can be improved by applying a heat treatment. Welded joints were made in various combinations, resulting in bimetallic or multilayered workpieces. Due to the negligible contact resistance, these joints can be appropriately used for applications in the electrotechnical field.

A Review of Friction Welding Research to Address the Influence, Development, Similar & Dissimilar Welding

S. Senthil Murugan, P. Sathiya — Thu, 28 Dec 2023 00:00:00 +0200

This review paper discusses the recent research work carried out in the frictional joining of dissimilar and similar alloys through the friction welding (FW) process with various parameters and modifications. It includes further the latest developments and advances in the research on FW and the influences of FW’s process parameters on the quality of joints and their properties. The specimens’ faying surfaces can also influence the joint properties as the surface modifications stimulate or change the metal joints’ bonding according to the welding parameters selected during FW. Though the rise of friction pressure (FP) during FW improves the strength of the joints, the improper selection of parameters leads to metal damage. It feels better if the axial shortening is less than 30 mm for FW of soft metals. The axial shortening values are less than 25 mm for the hemispherical bowl-type faying surfaces under 18 bar FP and it is noted that the bevel-type tapered faying surfaces increase the shortening. FW provided very narrow weld interfaces with around 5-10 µm width. With a low FP, it was possible to obtain a maximum of 100 % efficiency by modifying their faying surfaces. The small-diameter soft material needs less FP and friction time. The microstructure modification is possible and the weld joint is shown as U and V shapes for the bowl and tapered faying surfaces. It further increases the contact area and thus increases strength.

S-FMECA: A Novel Tool for Sustainable Product Design - Additive Manufacturing

N. Chtioui, R. Gaha, S. Chatti, A. Benamara — Thu, 28 Dec 2023 00:00:00 +0200

The choices made in the early design stage (EDS) will largely define the environmental impacts of a product. The purpose of this paper is to develop an eco-design method used for assessing semi-quantitatively the sustainability of an additively manufactured product since the EDS. This article presents a semi-quantitative method to support EDS-conscious environmental decisions. A novel Sustainable-Failure Mode, Effect, and Criticality Analysis (S-FMECA) tool is developed to support designers in the conceptual design phase, to guide the choices, and to provide a valuable evaluation of the future additively manufactured product. Through the integration of the environmental aspects in FMECA analysis, systematic prevention of errors, and enhancement of sustainability since the EDS would be the main advantage of this tool.

Parameter and Deposition Strategy Analysis for WAAM Processing of AISI 410 Stainless Steel

I. Pires, E. G. Assunção, M. C. Florescu, I. D. Savu, M. C. Criveanu, D. Klobčar — Fri, 29 Dec 2023 00:00:00 +0200

Wire + Arc Additive Manufacturing (WAAM®) is an additive manufacturing (AM) process capable of producing near net shape parts while reducing costs and thus gathering increased attention from researchers and manufacturers. Although a significant amount of work has already been published relating to the WAAM processing of stainless steels, it was mainly focused on austenitic stainless steels, with martensitic grades still lacking investigation. AISI 410 is a martensitic stainless steel that, due to its high hardness, demonstrates high wear resistance, being used in parts requiring high resistance to abrasion. Processing this material by WAAM allows for the creation of near net shape parts, leading to a reduction in machining, while at the same time allowing the creation of complex geometries which would be difficult, or outright impossible to obtain otherwise. In this work the effects of different processing parameters on WAAM processed AISI 410 steel, using Cold Metal Transfer (CMT) welding equipment, were investigated, as well as different deposition strategies for the fabrication of a test artifact using an AM software. It was demonstrated that it is possible to process AISI 410 steel by WAAM using an AM software to define deposition strategies and parameters based on the part design and previous experimental trials. The goal to deposit a complex part with high hardness and tensile strength, especially attractive properties to parts requiring high resistance to wear was achieved.

Comparative Analysis of Melt Pool Evolution in Selective Laser Melting of Inconel 625 and Inconel 718 Nickel-Based Superalloys

M. Ben Slama, S. Chatti, L. Kolsi — Thu, 28 Dec 2023 00:00:00 +0200

One of the key advantages of Additive Manufacturing is the versatility in working with a wide range of materials. Among these materials, Nickel-based superalloys have drawn great attention of specialists. This study investigates the behavior of Inconel 625 and Inconel 718 during selective laser melting. While these alloys have many similarities, thus their distinct chemical compositions determine different responses to this new process, which the authors aimed to elucidate in this study. Numerical simulations using ANSYS Additive® software were conducted to compare the melt pool dimensions (depth and width) of Inconel 625 and Inconel 718. The results reveal that the material's thermal properties play a significant role in determining the melt pool geometry. The Inconel 718 consistently exhibited larger melt pool dimensions than Inconel 625. The findings highlight the importance of understanding the connection between the material properties and process parameters.

Development and Optimisation of a Robot Arm System for Additive Manufacturing Applications

L. Stamorean, A. Feier, A. C. Firu — Thu, 28 Dec 2023 00:00:00 +0200

The paper presents the development of a new platform that represents a robotic arm system, useful and appropriate for the Additive Manufacturing applications. The main objective of this work was to explore the feasibility of integrating the off-the-shelf (COTS) Additive Manufacturing technologies and the six-degree-of-freedom industrial robotic arm, achieving a 3D Additive Manufacturing system which is able to perform six-degree fused deposition printing. The authors investigated the materials suitable to be used and performed more experiments with the aim to find the right configuration of the printing system. Finally, the technical issues reported during the experimental programme have been solved, the system being prepared to carry out workpieces with more complex shapes and more types of polymers.