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

Numerical Simulation of Microcellular Injection Molding: A Case Study

A. Chaabene, A. Ben Khalifa, S. Chatti — Fri, 13 Dec 2024 00:00:00 +0200

The microcellular injection molding, often referred to as MuCell®, is an innovative polymer processing technique that utilizes supercritical inert gases, such as CO₂ or N₂, to manufacture lightweight plastic products. This technology has gained significant attention in recent years due to environmental concerns and the increasing demand for lightweight components with superior mechanical properties. However, challenges related to surface finish quality and limited mechanical properties have impeded its widespread adoption. This paper provides a comprehensive overview of the microcellular injection molding process. To evaluate the practicality of the MuCell® process, an industrial case study is conducted, assessing its production reliability and overall product quality. A comparative rheological analysis is performed to discern the distinctions between MuCell® and traditional injection molding, thus validating the claimed advantages of microcellular injection. Based on the accrued findings, it is deduced that MuCell® proves to be a pertinent injection molding technique for fabricating lightweight plastic components featuring enhanced dimensional stability, reduced shrinkage, and minimized warping when compared to conventionally injection-molded parts.

Obtaining Metal-Ceramic Layers by Laser Cladding using Alumina Powder Mixtures

Fri, 13 Dec 2024 00:00:00 +0200

This paper presents a comparative analysis of the metal-ceramic powders mixtures behaviour deposited onto 304 stainless steel (SS304) substrate by laser procedure. Using Inconel 718 (In718) alloy as a matrix material that has a lower melting range in comparison with the austenitic stainless steel, a more reduced overheating phenomenon of the cladding layer has been achieved for the same values of the laser deposition parameters. On the other hand, due to the greater fluidity of the In718 alloy, comparing to the SS304 material, an increase of the cladded layer width has been observed at the macro and microstructure analysis. Moreover, an improvement of the adhesion phenomenon between the cladded layer and the substrate was found when spherical alumina (Al₂O₃₎particles have been used. The comparative analysis of the results in case of metal matrix composite (MMC), which was developed by mixing different percentages of Al₂O₃, SS304 or In718, has revealed that the laser power of 500W and cladding speed of 10mm/s are the optimal process parameters.

Dimensional Evaluation of Additively Manufactured Parts for Autonomous Vehicles

F. P. Berardi, P. H. A. Costa, V. B. Mendes, M. D. Banea — Thu, 12 Dec 2024 00:00:00 +0200

The growing use of drones in civilian and military applications is motivated mainly by reduced costs. Drones, along with autonomous vehicles, require lightweight structures and high dimensional accuracy to improve autonomy and spatial orientation. Additive Manufacturing (AM) enables the production of lightweight parts by controlling internal fill percentages and optimizing the density. However, there is limited research into how the type and percentage of infill affects dimensional tolerance. This study aims to assess the impact of these factors on 3D-printed parts, using low-cost FFF 3D printers with Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) filaments. Overall, the results were satisfactory and met the required tolerances, confirming the feasibility of using parts produced by low-cost 3D printers and commonly available materials in the mass production of drones and autonomous vehicles.

Machine Learning-Driven Parametric Analysis of Eco-Friendly Ultrasonic Welding for AL6061-CU Alloy Joints

A. Karan, S. Arungalai Vendan, M. R. Nagaraj, M. Chaturvedi, S. Sivadharmaraj — Fri, 13 Dec 2024 00:00:00 +0200

This study outlines the research conducted to examine the mechanical behaviour and microstructural characteristics of Al-Cu dissimilar wires joints welded using ultrasonic joining process that commonly finds application in automotive components, heat exchangers and electrical home and industrial appliances. The primary focus is on the metallurgical transformations to evaluate the pattern of molecular diffusion and spread within the weld, the consistency of diffusion, and the resulting alterations in strength caused by ultrasonic vibrational heat. This procedure entails conducting experimental trials to join the wire materials according to per design of experiments, wherein the process parameters significantly influencing the output are systematically varied, and consequently, subjecting the joints to shear testing. Subsequently, the welded specimens undergo microscopic examination and the images are captured using image analysers. In addition, scanning electron microscopy (SEM) pictures are examined to gain insights into the surface shape and assess the degree of weld production and performance. The findings demonstrate a direct correlation between the vibrational temperature and the weld strength. In addition, the joint surface exhibits a consistent weld pattern in the majority of the samples, with just a few instances of inconsistencies when the trail is carried out at low heat input. Electrical resistance at the joints is measured to understand the electrical parametric variations if any due to process parameters. A machine learning tool is employed to forecast the weld strength and joint resistance for differing ranges of process parametric values and accordingly optimize it.

External Factors Influence on Defects Detection by Scanning Contact Potentiometry

A. I. Alwaheba, V. I. Surin — Fri, 13 Dec 2024 00:00:00 +0200

Scanning contact potentiometry (SCP) method was used to detect structural inhomogeneities in a welded joint under the application of heat and constant electric current. For this purpose, a special sample was prepared, welded by manual arc welding from two halves of X8CrNiTi18-10 (Chromium-Nickel-titanium stainless Steel) austenitic steel, each with dimensions of 200×110×13.5mm. After welding, welded sample was inspected using X-ray radiography. The sample was stored for five months at room temperature, and the sample surface was scanned using different scanning speed ranging from 0.36 to 1.8 mm/sec. It was found that when scanning speed was increased, the signal values remained the same. In another experiment, a constant electric current was passed through the sample from 0.01 to 0.1A. Applying current led to the excitation of weak structural inhomogeneities from the welding joint butt, although it was machined. While heat led to an increase in diagnostic signal amplitude.

Multi-Response Optimization in AA6063/SS304 Bimetalic Friction Welding using Taguchi Grey Relational Analysis

S. Senthil Murugan, M. Vishnoi, S. Kattimani, T. G. Mamatha — Fri, 13 Dec 2024 00:00:00 +0200

This study aimed to create a robust joint between dissimilar materials, specifically AA6063-T6 aluminium alloy and SS304 austenitic stainless steel (ASS), and optimize the parameters. The experiments were conducted by employing the rotary friction welding (RFW) process, with an experimental setup devised on a conventional lathe machine utilizing friction-generated heat and plastic deformation. The joint's performance was evaluated as per ASTM standards through hardness and Charpy impact tests, demonstrating favourable results and the results were used for further analysis. Higher hardness was observed at higher friction pressure with higher speed of rotation. It reached a maximum of 85 HRC. Conversely, the maximum impact energy was obtained at low speed with 32 J. According to microstructure of the dissimilar joint, very narrow welding interface (WI) was found, which is less than 20 microns in width. The Taguchi-Grey relational analysis (GRA)-L9 method with Minitab software was utilized for optimize the process parameters, providing insights into effective parameter selection and multi-response optimization for improved performance. The results indicated that the welding speed was the most influential parameter. Weld pressure also influenced the weld zone’s hardness. Through the results, it is confirmed that RFW is emerged as a promising method for creating dissimilar joints, surpassing the limitations of fusion welding techniques.

Enhancing Friction Stir Welding Performance: Finite Element Simulation Study using Filler Material

S. Rached, A. Chaabene, S. Chatti — Thu, 12 Dec 2024 00:00:00 +0200

Friction Stir Welding (FSW) is a groundbreaking method that revolutionizes welding by utilizing friction-induced heat to join metals without melting them. In this study, we conducted a comprehensive investigation into the FSW process using the numerical software Simufact Forming, focusing on the critical aspect of introducing filler material during the welding operation. Our work involved meticulous simulations to analyze the impact of filler material on the quality and integrity of the weld joint. Through detailed modelling and parameter optimization, we successfully demonstrated the significance of the refill stage in achieving superior welding outcomes. Our main results reveal a substantial enhancement in the weld joint's mechanical and metallurgical properties when filler material is strategically introduced. The simulations provided valuable insights into the optimal conditions for the refill stage, including tool movement, material feeding rates, and key process parameters. These findings contribute to the ongoing efforts in refining FSW techniques, facilitating the development of high-performance welded joints.

Wear Enhancement of High Yield Steels using Laser Cladding

D. C. Cuculea, C. Iatan, G. Ardelean, E. M. Stanciu, A. Pascu — Fri, 13 Dec 2024 00:00:00 +0200

Laser cladding is a process that uses laser beam as a heat source to melt metallic powder, generating a layer that improves or produces a new surface. The current study aims to improve the base material surface by applying a layer of high alloy nickel via the coaxial laser cladding procedure. The experimental tests were conducted utilizing S700MC steel as base material, owing to its widespread industrial application in agriculture for various components. The cladding tests were performed with a Trumpf TruPulse 556 pulsed laser and a PRECITEC coaxial cladding module. To determine mechanical behaviour, the samples were analysed using optical and electronic microscopy, EDS, microhardness, and wear resistance. The results show that NiCrBSi powder is a suitable material for repairing the S700MC steel and increase the lifespan of components.

Modelling and Simulation for a Versatile Controllable Power Supply Configuration Appropriate for Magnetically Impelled Arc Butt (MIAB) Welding

G. C. Ganesha, M. Chaturvedi, S. Arungalai Vendan, S. Theodore Chandra — Fri, 13 Dec 2024 00:00:00 +0200

This article presents the design and development of a power source for industrial applications, focusing on improving energy efficiency, control, and reliability. The study is primarily focused on designing an optimized electrical power source for Magnetically Impelled Arc Butt (MIAB) welding, which is a solid-state welding process characterized by specific current requirements. MIAB welding involves variation of current in two stages of the welding sequence. The objective of this study is to propose an appropriate power supply configuration that meets the precise amperage control and also ensures machine compactness and automation of the process. Utilizing state-of-the-art simulation tools, the research explores various design parameters and configurations to achieve the desired current modulation efficiently. The inverter-based welding power source is tested for the welding of tubes of MS1018 material by implementing parametric variations to validate its workability and performance. The findings indicate that the proposed power supply configuration can enable the required control and also provide a compact power supply unit for MIAB welding, paving the way for its broader industrial adoption and implementation. This research contributes to the advancement of welding technology by providing a robust solution to the challenges associated with arc dynamics and amperage modulation in MIAB welding, ultimately leading to improved weld quality and process efficiency. The proposed power supply design demonstrates potential applications well beyond MIAB welding, offering versatility for any process requiring controlled amperage variation during its operation cycle.

Material Investigation and Effect of Printing Orientation, Tensile Speed, and Density on the Mechanical Behaviour of 3D Printed Parts

K. Ben Amor, S. Chatti, B. Louhichi — Fri, 13 Dec 2024 00:00:00 +0200

Additive manufacturing (AM), also known as 3D printing, is becoming one of the main manufacturing sources in most fields, due to its easy manipulation and time, and cost savings. It is the most favourable manufacturing technology for prototyping, unit or limited production size, and personalized objects. However, the AM's most common problem found is the lack of material information due to the different printing parameters and different materials. The fused deposition modelling (FDM) is the mostly used AM technology since it is the cheapest and easiest manufacturing technique. This technology has various materials and printing parameters that affect the mechanical properties. Multiple types of research were made on the effect of the different printing parameters, other on the material properties, and few worked on the effect of different materials. In the scope of our work, the effect of the printing orientation on different materials and the effect of varying the density on the mechanical behaviour are investigated. Moreover, the FDM part’s mechanical behaviour is still on investigation. We investigated the effect of tensile tests with different speeds on the specimens to analyse this behaviour. For this purpose, we printed different tensile specimens with different materials, printing directions, and densities. Then, we studied the effect of each parameter on the mechanical behaviour using tensile tests. It was found out that the printing parameters have a significant impact on the mechanical properties, but the tensile speed doesn’t affect the behaviour if the test is made at an environmental temperature.

A Review of Insights and Research Progress on Hard Turning

S. Girisankar, S. Senthil Murugan, E. Shankar — Fri, 13 Dec 2024 00:00:00 +0200

Of late, due to the launch of improved machine tool designs and extremely hard cutting tools, “Hard Turning” (HT) or “Hard Finish Turning” (HFT) has turned out to be an innovative, cost-effective, and smart alternative to the traditional grinding and subsequent superfinishing processes. As a result, HT clenches the potential to produce excellent part quality in very little time along with negligible additional costs, which is considered to be a boon for the manufacturing industries. Hence, an attempt was made to review the development, key insights, and research progress in the HT process. So, a huge pool of HT studies has been reviewed to achieve a better understanding of the evolution and key insights namely process, workpiece materials, cutting inserts, machine tools, and machining parameters. Additionally, the effectiveness of HT using CBN (Cubic Boron Nitride) insert under different machining conditions is briefed. The review highlights the growing potential of HT in modern manufacturing and outlines the challenges and future research direction.

A Regularized Interface Model for Simulating the Response of Adhesive Joints

N. Valoroso — Fri, 13 Dec 2024 00:00:00 +0200

A regularized interface damage model is presented grounded on the cohesive-zone concept. This is obtained using a gradient-based formulation, which is equivalent to the introduction of the laplacian of a scalar damage field into the threshold function of the corresponding local model. Unlike the classical cohesive-zone formulations, damage is driven by a non-local energy release rate and the size of the process zone is controlled by an independent model parameter. The capabilities of the proposed approach are show via a mode-I fracture problem for an adhesive joint. Numerical results illustrate the effects of the gradient dependence against the usual cohesive zone implementation.