Seam Welding of Aluminum Sheet Using Ultrasonic Additive Manufacturing System

Author(s):  
Paul J. Wolcott ◽  
Christopher Pawlowski ◽  
Leon M. Headings ◽  
Marcelo J. Dapino

Ultrasonic welding was investigated as a method of joining 0.076 in. (1.93 mm) thick aluminum 6061 flat sheet material. Joints were produced with ultrasonic additive manufacturing (UAM) equipment in a modified application of the ultrasonic welding process. Through joint design development, successful welds were achieved with a scarf joint configuration. Using a design of experiments (DOE) approach, weld parameters including weld amplitude, scarf angle, and weld speed were optimized for mechanical strength. Lower angles and higher amplitudes were found to provide the highest strengths within the levels tested. Finite-element studies indicate that 5 deg and 10 deg angles produce an increased relative motion of the workpieces as compared to 15 deg, 20 deg, and 25 deg angles, likely leading to increased strength. Successful joints showed no indication of voids under optical microscopy. As-welded joints produce tensile strengths of 221 MPa, while heat treated joints produce tensile strengths of 310 MPa, comparable to heat treated bulk material. High-temperature tensile testing was conducted at 210 °C, with samples exhibiting strengths of 184.1 MPa, similar to bulk material. Room temperature fatigue testing resulted in cyclic failures at approximately 190,000 cycles on average, approaching that of bulk material.

2020 ◽  
Author(s):  
Omar Fergani ◽  
Katharina Eissing ◽  
Teresa Perez Prado ◽  
Ole Geisen

The industrial use of laser powder-bed fusion (L-PBF) in turbomachinery is gaining momentum renderingthe inspection and quali?cation of certain post-processing steps necessary. This includes fusiontechniques that allow to print multiple parts separately to take advantage of e.g. various print orientationsand join them subsequently. The main motivation of this study is to validate the tungsten inertgas (TIG) welding process of L-PBF manufactured parts using industrial speci?cations relevant for gasturbines to pave the way for the industrial production of modular build setups. For this, two commonlyused nickel-based super alloys for high-temperature applications, Inconel 718 and Inconel 625 are chosen.Since their defect-free printability has been established widely, we focus on the suitability to be joined usingTIG welding. The process is evaluated performing microstructural examination and mechanical testsin as-built as well as heat-treated samples. The welds are assessed by applying a general weld quali?cationapproach used at Siemens Gas and Power. It was found that both materials can be joined via TIGwelding using standard weld parameters causing minimal defects. A solution annealing heat treatmentbefore welding is not necessary for a positive outcome, but still recommended for Inconel 718.


2007 ◽  
Vol 551-552 ◽  
pp. 447-452
Author(s):  
V.M. Imayev ◽  
Renat M. Imayev ◽  
Timur G. Khismatullin ◽  
Gennady A. Salishchev

A novel approach to fabrication of globularized fine-grained structure in γ+α2 titanium aluminide alloys has been proposed. The approach included the use of a specially designed alloy Ti-43Al-X(Nb,Mo,B) and heat treatment. It was found that the ingot structure of the alloy might be partially globularized on a scale of bulk material using only globularization anneal excluding any hot working procedure. The microstructure and tensile mechanical properties of the alloy in the cast + heat treated condition were investigated. The tensile mechanical tests were performed in air in the temperature range of T=900-1130°C at an initial strain rate of ε′=1.7×10-4 s-1. High elongation (δ=160-230%) and low flow stresses (σ=36-100 MPa) typical of superplastic behavior were measured at T=1050-1130°C. It was demonstrated that the sheet material produced by spark cutting of the cast + heat treated alloy might be successfully hot formed.


Author(s):  
Tianyang Han ◽  
Leon M Headings ◽  
Ryan Hahnlen ◽  
Marcelo J. Dapino

Abstract Ultrasonic additive manufacturing (UAM) is a solid state manufacturing process capable of producing near-net-shape metal parts. Recent studies have shown the promise of UAM welding of high strength steels. However, the effect of weld parameters on the weld quality of UAM steel is unclear. A design of experiments study based on a Taguchi L16 design array was conducted to investigate the influence of parameters including baseplate temperature, amplitude, welding speed, and normal force on the interfacial temperature and shear strength of UAM welding of carbon steel 4130. Analysis of variance (ANOVA) and main effects analyses were performed to determine optimal weld parameters within the process window. A Pearson correlation test was conducted to find the relationship between interfacial temperature and shear strength. These analyses indicate that the highest shear strength of 392.8 MPa can be achieved by using a baseplate temperature of 400°F (204.4°C), amplitude of 31.5 μm, welding speed of 40 in/min (16.93 mm/s), and normal force of 6000 N. The Pearson correlation coefficient is calculated as 0.227, which indicates a weak positive correlation between interfacial temperature and shear strength over the range tested.


Author(s):  
Sagil James ◽  
Abhishek Sonate ◽  
Christopher Dang ◽  
Lenny De La Luz

Carbon fiber reinforced plastic (CFRP) are advanced engineering materials which are recognized as the most sought-after composite for several industrial applications including aerospace and automotive sectors. CFRP have superior physical and mechanical properties such as lightweight, high resilience, high-durability and high strength-to-weight ratio. CFRP composites stacked up with titanium to form multi-layered material stacks to enhance its load bearing capability. Traditional methods of stacking up CFRP and titanium involves using either high strength adhesives or rivets and bolts. The laminate structures joined by these methods often tend to fail during high load-bearing applications. Conventional metal welding technologies use high heat causing high thermal stresses and microstructural damages. Ultrasonic welding is a solid-state joining process, which has the capability of welding dissimilar materials at relatively low temperatures using ultrasonic vibration. Ultrasonic additive manufacturing (UAM) process is an ideal method to weld CFRP and Titanium. During the ultrasonic welding process, two dissimilar materials under a continuous static load are subjected to transverse ultrasonic vibrations, which results in high stress and friction between the two surfaces. This research focuses on the study of ultrasonically welding CFRP and Titanium stacks using UAM process. The study involves experimentation performed on an in-house built UAM setup. Finite element analysis is performed to understand the distribution stresses and strains during the UAM process. In this study, CFRP and Titanium layers are successfully welded using UAM process without causing any melting or significant heating. The finite element analysis study revealed that during UAM process, CFRP/Titanium stacks are subject to repeated cyclic shear stress reversals resulting in a strong weld joint. The stress-strain diagram during the process showed a considerable increase in plastic strain during the UAM process. The outcomes of this study can be used to further the industrial applications of the ultrasonic additive process as well as other ultrasonic welding based processes involving dissimilar materials.


2021 ◽  
Vol 11 (10) ◽  
pp. 4694
Author(s):  
Christian Wacker ◽  
Markus Köhler ◽  
Martin David ◽  
Franziska Aschersleben ◽  
Felix Gabriel ◽  
...  

Wire arc additive manufacturing (WAAM) is a direct energy deposition (DED) process with high deposition rates, but deformation and distortion can occur due to the high energy input and resulting strains. Despite great efforts, the prediction of distortion and resulting geometry in additive manufacturing processes using WAAM remains challenging. In this work, an artificial neural network (ANN) is established to predict welding distortion and geometric accuracy for multilayer WAAM structures. For demonstration purposes, the ANN creation process is presented on a smaller scale for multilayer beads on plate welds on a thin substrate sheet. Multiple concepts for the creation of ANNs and the handling of outliers are developed, implemented, and compared. Good results have been achieved by applying an enhanced ANN using deformation and geometry from the previously deposited layer. With further adaptions to this method, a prediction of additive welded structures, geometries, and shapes in defined segments is conceivable, which would enable a multitude of applications for ANNs in the WAAM-Process, especially for applications closer to industrial use cases. It would be feasible to use them as preparatory measures for multi-segmented structures as well as an application during the welding process to continuously adapt parameters for a higher resulting component quality.


Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1746
Author(s):  
Iñigo Calderon-Uriszar-Aldaca ◽  
Sergio Perez ◽  
Ravi Sinha ◽  
Maria Camara-Torres ◽  
Sara Villanueva ◽  
...  

Additive manufacturing (AM) of scaffolds enables the fabrication of customized patient-specific implants for tissue regeneration. Scaffold customization does not involve only the macroscale shape of the final implant, but also their microscopic pore geometry and material properties, which are dependent on optimizable topology. A good match between the experimental data of AM scaffolds and the models is obtained when there is just a few millimetres at least in one direction. Here, we describe a methodology to perform finite element modelling on AM scaffolds for bone tissue regeneration with clinically relevant dimensions (i.e., volume > 1 cm3). The simulation used an equivalent cubic eight node finite elements mesh, and the materials properties were derived both empirically and numerically, from bulk material direct testing and simulated tests on scaffolds. The experimental validation was performed using poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) copolymers and 45 wt% nano hydroxyapatite fillers composites. By applying this methodology on three separate scaffold architectures with volumes larger than 1 cm3, the simulations overestimated the scaffold performance, resulting in 150–290% stiffer than average values obtained in the validation tests. The results mismatch highlighted the relevance of the lack of printing accuracy that is characteristic of the additive manufacturing process. Accordingly, a sensitivity analysis was performed on nine detected uncertainty sources, studying their influence. After the definition of acceptable execution tolerances and reliability levels, a design factor was defined to calibrate the methodology under expectable and conservative scenarios.


2013 ◽  
Vol 690-693 ◽  
pp. 2621-2624
Author(s):  
Bo Chen ◽  
Ji Cai Feng

Underwater weld technology is urgently needed for the widely development of marine recourses, and weld automation technology is the inevitable choice because of the underwater environment. Because of the influence of the rigorous environment, the weld seam forming of underwater wet welding is very poor. To control the weld seam forming automatically, the model between the weld parameters and the weld seam shape must be built. This paper used arc sensor to monitor the electrical information of underwater wet welding process, and regression method was used to model the process, and the factors that influence the weld seam forming mostly were analyzed.


2021 ◽  
pp. 002199832097681
Author(s):  
F Köhler ◽  
IF Villegas ◽  
C Dransfeld ◽  
A Herrmann

Ultrasonic welding is a promising technology to join fibre-reinforced thermoplastic composites. While current studies are mostly limited to fabric materials the applicability to unidirectional materials, as found in aerospace structures, would offer opportunities for joining primary aircraft structures. However, due to the highly anisotropic flow of a molten unidirectional ply undesired squeeze flow phenomena can occur at the edges of the weld overlap. This paper investigates how the fibre orientation in the plies adjacent to the weld line influences the welding process and the appearance of edge defects. Ultrasonic welding experiments with different layups and energy director configurations were carried out while monitoring temperatures at different locations inside and outside the weld overlap. The joints were characterized by single lap shear tests, analysis of corresponding fracture surfaces and microscopic cross-sections. Results showed that the anisotropic flow and the anisotropic thermal conductivity of the plies adjacent to the weld line have a distinct effect on the appearance and location of edge defects. By using energy directors that cover only part of the weld overlap area a new approach was developed to mitigate edge defects caused by the highly directional properties of the unidirectional plies.


2014 ◽  
Vol 657 ◽  
pp. 306-310
Author(s):  
Lăcrămioara Apetrei ◽  
Vasile Rață ◽  
Ruxandra Rață ◽  
Elena Raluca Bulai

Research evolution timely tendencies, in the nonconventional technologies field, are: manufacture conditions optimization and complex equipments design. The increasing of ultrasonic machining use, in various technologies is due to the expanding need of a wide range materials and high quality manufacture standards in many activity fields. This paper present a experimental study made in order to analyze the welded zone material structure and welding quality. The effects of aluminium ultrasonic welding parameters such as relative energy, machining time, amplitude and working force were compared through traction tests values and microstructural analysis. Microhardness tests were, also, made in five different points, two in the base material and three in the welded zone, on each welded aluminium sample. The aluminum welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara. The ultrasonic welding temperature is lower than the aluminium melting temperature, that's so our experiments reveal that the aluminium ultrasonic welding process doesn't determine the appearance of moulding structure. In the joint we have only crystalline grains deformation, phase transformation and aluminium diffusion.


2007 ◽  
Vol 539-543 ◽  
pp. 3832-3837 ◽  
Author(s):  
D. Jacquin ◽  
Christophe Desrayaud ◽  
Frank Montheillet

The thermo-mechanical simulation of Friction Stir Welding focuses the interest of the welding scientific and technical community. However, literature reporting material flow modeling is rather poor. The present work is based on the model developed by Heurtier [2004] and aims at improving this thermo-fluid simulation developed by means of fluid mechanics numerical and analytical velocity fields combined together. These various velocity fields are investigated separately and especially according to the power dissipated during the flow. Boundary conditions are considered through a new approach based on the kinematic analysis of the thread of the pin. An equilibrium is established between the vertical motion of the bulk material dragged in the depth of the metal sheet, and its partial circulation around the pin. The analyses of the obtained velocity fields enable the understanding of the welded zone asymmetry and highlights the bulk material mixing between the welded coupons in the depth of the sheet. A regression is performed on the relative sliding velocity of the aluminium according to the surface of the tool: shoulder and pin. Two dimension flow lines in the depth of the metal sheet are then obtained and successfully compared with the results obtained by Colegrove (2004) [1].


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