A shape control strategy for wire arc additive manufacturing of thin-walled aluminium structures with sharp corners

2021 ◽  
Vol 64 ◽  
pp. 253-264
Author(s):  
Donghong Ding ◽  
Runzhuo Zhao ◽  
Qinghua Lu ◽  
Zengxi Pan ◽  
Huijun Li ◽  
...  
2020 ◽  
Vol 58 (4) ◽  
pp. 461
Author(s):  
Van Thao Le ◽  
Quang Huy Hoang ◽  
Van Chau Tran ◽  
Dinh Si Mai ◽  
Duc Manh Dinh ◽  
...  

Wire arc additive manufacturing (WAAM) is nowadays gaining much attention from both the academic and industrial sectors for the manufacture of medium and large dimension metal parts because of its high deposition rate and low costs of equipment investment. In the literature, WAAM has been extensively investigated in terms of the shape and dimension accuracy of built parts. However, limited research has focused on the effects of welding parameters on the microstructural characteristics of parts manufactured by this process. In this paper, the effects of welding current in the WAAM process on the shape and the microstructure formation of built thin-walled low-carbon steel components were studied. For this purpose, the thin-walled low-carbon steel samples were built layer-by-layer on the substrates by using an industrial gas metal arc welding robot with different levels of welding current. The shape, microstructures and mechanical properties of built samples were then analyzed. The obtained results show that the welding current plays an important role in the shape stability, but does not significantly influence on the microstructure formation of built thin-walled samples. The increase of the welding current only leads to coarser grain size and resulting in decreasing the hardness of built materials in each zone of the built sample. The mechanical properties (hardness and tensile properties) of the WAAM-built thin-walled low-carbon steel parts are also comparable to those of wrought low-carbon steel, and to be adequate with real applications.


2019 ◽  
Vol 26 (3) ◽  
pp. 499-508
Author(s):  
Yun Zhao ◽  
Fang Li ◽  
Shujun Chen ◽  
Zhenyang Lu

Purpose The purpose of this paper is to develop a build strategy for inclined thin-walled parts by exploiting the inherent overhanging capability of the cold metal transfer (CMT) process, which release wire-arc additive manufacturing from tedious programming work and restriction of producible size of parts. Design/methodology/approach Inclined thin-walled parts were fabricated with vertically placed welding torch free from any auxiliary equipment. The inclined features were defined and analyzed based on the geometrical model of inclined parts. A statistical prediction model was developed to describe the dependence of inclined geometrical features on process variables. Based on these models, a build strategy was proposed to plan tool path and output process parameters. After that, the flow work was illustrated by fabricating a vase part. Findings The formation mechanism and regulation of inclined geometrical features were revealed by conducting experimental trials. The inclined angle can be significantly increased along with the travel speed and offset distance, whereas the wall width is mainly dependent on the ratio of wire feed speed to travel speed. In contrast to other welding process, CMT has a stronger overhanging capability, which provides the possibility to fabricate parts with large overhanging features directly with high forming accuracy. Originality/value This paper describes a novel build strategy for inclined thin-walled parts free from any auxiliary equipment. With the proposed strategy, a complex structural component can be deposited directly in the rectangular coordinates additive manufacturing system, indicating infinite possibilities on the producible size of the parts. Moreover, equipment requirements and tedious program work can also be significantly reduced.


Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 678
Author(s):  
Mikel Casuso ◽  
Fernando Veiga ◽  
Alfredo Suárez ◽  
Trunal Bhujangrao ◽  
Eider Aldalur ◽  
...  

Gas Metal Arc Welding (GMAW) is a manufacturing technology included within the different Wire Arc Additive Manufacturing alternatives. These technologies have been generating great attention among scientists in recent decades. Its main qualities that make it highly productive with a large use of material with relatively inexpensive machine solutions make it a very advantageous technology. This paper covers the application of this technology for the manufacture of thin-walled parts. A finite element model is presented for estimating the deformations in this type of parts. This paper presents a simulation model that predicts temperatures with less than 5% error and deformations of the final part that, although quantitatively has errors of 20%, qualitatively allows to know the deformation modes of the part. Knowing the part areas subject to greater deformation may allow the future adaptation of deposition strategies or redesigns for their adaptation. These models are very useful both at a scientific and industrial level since when we find ourselves with a technology oriented to Near Net Shape (NNS) manufacturing where deformations are critical for obtaining the final part in a quality regime.


Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1141
Author(s):  
Leandro João da Silva ◽  
Henrique Nardon Ferraresi ◽  
Douglas Bezerra Araújo ◽  
Ruham Pablo Reis ◽  
Américo Scotti

The present paper aimed at assessing the effect of two thermal management approaches on geometry and productivity of thin-walled structures built by Wire + Arc Additive Manufacturing (WAAM). Thin-walls of ER 5356 (Al5Mg) with different lengths and the same number of layers were deposited via the gas metal arc (GMA) process with the aid of an active cooling technique (near-immersion active cooling—NIAC) under a fixed set of deposition parameters. Then, the same experiment was performed with natural cooling (NC) in air. To characterize the thermal management approaches, the interpass temperature (i.e., the temperature at which subsequent layers are deposited) were monitored by a trailing/leading infrared pyrometer during the deposition time. Finally, thin walls with a fixed length were deposited using the NC and NIAC approaches with equivalent interpass temperatures. As expected, the shorter the wall length the more intense the deposition concentration, heat accumulation, and, thus, geometric deviation. This behavior was more evident and premature for the NC strategy due to its lower heat sinking effectiveness. The main finding was that, regardless of the thermal management technique applied, if the same interpass temperature is selected and maintained, the geometry of the part being built tends to be stable and very similar. However, the total deposition time is somewhat shorter with the NIAC technique due its greater heat sinking advantage. Thus, the NIAC technique facilitates the non-stop manufacturing of small parts and details via WAAM.


Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 848
Author(s):  
Tao Feng ◽  
Lishi Wang ◽  
Zhongmin Tang ◽  
Shanwen Yu ◽  
Zhixiang Bu ◽  
...  

Curvature effects are typically present in the process of additive manufacturing (AM), particularly for wire arc additive manufacturing. In this paper, stainless-steel wire was adopted to deposit thin-walled samples with different curvatures. Optical microscopy, SEM, EDS and micro-hardness was used to analyse the microstructure, composition and properties of the samples. The result shows that the bottom region of the thin-walled sample had a mainly planar and cellular crystal microstructure. For the middle region, the microstructure revealed mainly dendrites, and the top layer has equiaxed dendrite morphology. The microhardness value of the bottom was greater than that of the middle, and the microhardness value of the middle was greater than that of the top. Moreover, the grain size of the inner part (direct to curvature radius) was larger than that of the outer part, and the micro-hardness value exhibited an increasing tendency from the inner to the outer side. With enlarging curvature, the degree of grain size differences and micro-hardness variants decreased. Finally, an investigation with a low carbon steel wire showed that it had a similar curvature effect for its AM specimen.


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