Bead Modelling and Deposition Path Planning in Wire Arc Additive Manufacturing of Three Dimensional Parts

2019 ◽  
Vol 969 ◽  
pp. 582-588 ◽  
Author(s):  
Ashish Kumar ◽  
Kuntal Maji

This paper presents investigations on the manufacturing of three-dimensional functional metallic parts through melting and deposition of stainless steel 430L wire material by a metal inert gas welding technique. Experiments were performed on wire arc additive manufacturing following face centered composite design of experiments considering voltage, current, electrode wire material feed rate and welding speed as inputs for modeling single bead geometry in terms of bead width, height, and cross-sectional area. Response surface models were built using the collected experimental data. Performance of the models in predicting the responses was found satisfactory. Models of single bead geometry were employed to calculate void and post-processing in fabricating three-dimensional parts following raster scanning deposition of multiple layers considering the different degree of overlapping and build directions. The theoretically estimated values of void and post-processing were verified through fabrications of two three-dimensional shapes. It was shown that the void and post-processing could be controlled by suitable selection of process parameters, the degree of overlapping between two beads and build direction.

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1211
Author(s):  
Hee-keun Lee ◽  
Jisun Kim ◽  
Changmin Pyo ◽  
Jaewoong Kim

The wire arc additive manufacturing (WAAM) process used to manufacture aluminum parts has a number of variables. This study focuses on the effects of the heat input and the current and voltage ratio on the deposition efficiency. The effects of the heat input and current and voltage ratio (V/A) on the bead geometry were analyzed, depending on the cross-sectional geometry of the deposition layers, for nine different deposition conditions. The deposition efficiency was also analyzed by analyzing the cross-sectional geometry of the thin-wall parts made of aluminum. The heat input range was about 2.7 kJ/cm to 4.5 kJ/cm; the higher the heat input, the higher the deposition efficiency. The maximum deposition efficiency achieved in this study was 76%. The current and voltage ratio was used to quantify the portion of voltage (V) in the total heat input (Q), and the effect on the bead geometry was analyzed. As the portion of voltage in the quasi heat input decreased by about 10%, it was found that the deposition efficiency was decreased by 1% to 3%.


2020 ◽  
Vol 71 (4) ◽  
pp. 431-443 ◽  
Author(s):  
Le Van Thao ◽  
Mai Dinh Si ◽  
Doan Tat Khoa ◽  
Hoang Quang Huy

In the wire arc additive manufacturing (WAAM) process, the geometry of single welding beads has significant effects on the stability process and the final quality and shape of manufactured parts. In this paper, the geometry of single welding beads of 308L stainless steel was predicted as functions of process parameters (i.e. welding current I, voltage U, and travel speed v) by using the response surface methodology (RSM). A set of experimental runs was carried out by using the Box-Behnken design method. The adequacy of the developed models was assessed by using an analysis of variance (ANOVA). The results indicate that the RSM allows the predictive models of bead width (BW) and bead height (BH) to be developed with a high accuracy: R2-values of BW and BH are 99.01% and 99.61%, respectively. The errors between the predicted and experimental values for the confirmatory experiments are also lower than 5% that again confirms the adequacy of the developed models. These developed models can efficiently be used to predict the desirable geometry of welding beads for the adaptive slicing principle in WAAM.


Author(s):  
Yashwant Koli ◽  
N Yuvaraj ◽  
Aravindan Sivanandam ◽  
Vipin

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.


2021 ◽  
Author(s):  
Raphael Bertani ◽  
Caio Moreno Perret Novo ◽  
Pedro Henrique Freitas ◽  
Amanda Amorin Nunes ◽  
Thiago Nunes Palhares ◽  
...  

Abstract We present a detailed step-by-step approach for the low-cost production and surgical implantation of cranial prostheses, aimed at restoring aesthetics, cerebral protection, and facilitating neurological rehabilitation. This protocol uses combined scan computed tomography (CT) cross-sectional images, in DICOM format, along with a 3D printing (additive manufacturing) setup. The in-house developed software InVesalius®️ is an open-source tool for medical imaging manipulation. The protocol describes image acquisition (CT scanning) procedures, and image post-processing procedures such as image segmentation, surface/volume rendering, mesh generation of a 3D digital model of the cranial defect and the desired prostheses, and their preparation for use in 3D printers. Furthermore, the protocol describes a detailed powder bed fusion additive manufacturing process, known as Selective Laser Sintering (SLS), using Polyamide (PA12) as feedstock to produce a 3-piece customized printed set per patient. Each set consists of a “cranial defect printout” and a “testing prosthesis” to assemble parts for precision testing, and a cranial “prostheses mold” in 2 parts to allow for the intraoperative modeling of the final implant cast using the medical grade Poly(methyl methacrylate) (PMMA) in a time span of a few min. The entire 3D processing time, including modelling, design, production, post-processing and qualification, takes approximately 42 h. Modeling the PMMA flap with a critical thickness of 4 mm by means of Finite Element Method (FEM) assures mechanical and impact properties to be slightly weaker than the bone tissue around it, a safety design to prevent fracturing the skull after a possible subsequent episode of head injury. On a parallel track, the Protocol seeks to provide guidance in the context of equipment, manufacturing cost and troubleshooting. Customized 3D PMMA prostheses offers a reduced operating time, good biocompatibility, and great functional and aesthetic outcomes. Additionally, it offers greater than 15-fold cost advantage over the usage of other materials, including metallic parts produced by additive manufacturing.


Measurement ◽  
2021 ◽  
pp. 110452
Author(s):  
Fernando Veiga ◽  
Alfredo Suarez ◽  
Eider Aldalur ◽  
Teresa Artaza

2021 ◽  
Author(s):  
Ashish Kulkarni ◽  
Prahar M. Bhatt ◽  
Alec Kanyuck ◽  
Satyandra K. Gupta

Abstract Robotic Wire Arc Additive Manufacturing (WAAM) is the layer-by-layer deposition of molten metal to build a three-dimensional part. In this process, the fed metal wire is melted using an electric arc as a heat source. The process is sensitive to the arc conditions, such as arc length. While building WAAM parts, the metal beads overlap at corners causing material accumulation. Material accumulation is undesirable as it leads to uneven build height and process failures caused by arc length variation. This paper introduces a deposition speed regulation scheme to avoid the corner accumulation problem and build parts with uniform build height. The regulated speed has a complex relationship with the corner angle, bead geometry, and molten metal dynamics. So we need to train a model that can predict suitable speed regulations for corner angles encountered while building the part. We develop an unsupervised learning technique to characterize the uniformity of the bead profile of a WAAM built layer and check for anomalous bead profiles. We train a model using these results that can predict suitable speed regulation parameters for different corner angles. We test this model by building a WAAM part using our speed regulation scheme and validate if the built part has uniform build height and reduced corner defects.


Author(s):  
Ganzi Suresh

Additive manufacturing (AM) is also known as 3D printing and classifies various advanced manufacturing processes that are used to manufacture three dimensional parts or components with a digital file in a sequential layer-by-layer. This chapter gives a clear insight into the various AM processes that are popular and under development. AM processes are broadly classified into seven categories based on the type of the technology used such as source of heat (ultraviolet light, laser) and type materials (resigns, polymers, metal and metal alloys) used to fabricate the parts. These AM processes have their own merits and demerits depending upon the end part application. Some of these AM processes require extensive post-processing in order to get the finished part. For this process, a separate machine is required to overcome this hurdle in AM; hybrid manufacturing comes into the picture with building and post-processing the part in the same machine. This chapter also discusses the fourth industrial revolution (I 4.0) from the perspective of additive manufacturing.


2016 ◽  
Vol 2016 (CICMT) ◽  
pp. 000001-000005
Author(s):  
Soshu Kirihara

Abstract In a stereolithographic additive manufacturing (AM), two dimensional (2D) cross sectional patterns were created through photo polymerization by ultraviolet laser drawing on spread resin paste including ceramic nanoparticles, and three dimensional (3D) composite models were sterically printed by layer lamination through chemical bonding. An automatic collimeter was equipped with the laser scanner to adjust beam diameter. Fine or coarse beams could realize high resolution or wide area drawings, respectively. Metal and ceramic bulky components including dendritic networks were geometrically built by using stereolithographic AM. Geometric patterns with periodic, self-similar, graded and fluctuated arrangements were created by computer aided design, manufacture and evaluation (CAD/CAM/CAE) for effective modulations of energy and material flows through dielectric lattices in photonic crystals, porous electrodes in fuel cells and biological scaffolds in artificial bones.


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