Measuring the effects of a laser beam on melt pool fluctuation in arc additive manufacturing

2019 ◽  
Vol 25 (3) ◽  
pp. 488-495
Author(s):  
Jonas Näsström ◽  
Frank Brückner ◽  
Alexander F.H. Kaplan
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
High Speed ◽  
Surface Profile ◽  
High Speed Imaging ◽  
Cold Metal Transfer ◽  
Content Type ◽  
Pool Surface ◽  
Melt Pool ◽  
Cold Metal

Purpose The steadily growing popularity of additive manufacturing (AM) increases the demand for understanding fundamental behaviors of these processes. High-speed imaging (HSI) can be a useful tool to observe these behaviors, but many studies only present qualitative analysis. The purpose of this paper is to propose an algorithm-assisted method as an intermediate to rapidly quantify data from HSI. Here, the method is used to study melt pool surface profile movement in a cold metal transfer-based (CMT-based) AM process, and how it changes when the process is augmented with a laser beam. Design/methodology/approach Single-track wide walls are generated in multiple layers using only CMT, CMT with leading and with trailing laser beam while observing the processes using HSI. The studied features are manually traced in multiple HSI frames. Algorithms are then used for sorting measurement points and generating feature curves for easier comparison. Findings Using this method, it is found that the fluctuation of the melt surface in the chosen CMT AM process can be reduced by more than 35 per cent with the addition of a laser beam trailing behind the arc. This indicates that arc and laser can be a viable combination for AM. Originality/value The suggested quantification method was used successfully for the laser-arc hybrid process and can also be applied for studies of many other AM processes where HSI is implemented. This can help fortify and expand the understanding of many phenomena in AM that were previously too difficult to measure.

From mine to part: directed energy deposition of iron ore

2021 ◽  
Vol 27 (11) ◽  
pp. 37-42
Author(s):  
Himani Naesstroem ◽  
Frank Brueckner ◽  
Alexander F.H. Kaplan
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
High Speed ◽  
Iron Ore ◽  
Energy Deposition ◽  
Content Type ◽  
Melt Pool ◽  
Directed Energy Deposition ◽  
Directed Energy ◽  
Melt Pool Size

Purpose This paper aims to gain an understanding of the behaviour of iron ore when melted by a laser beam in a continuous manner. This fundamental knowledge is essential to further develop additive manufacturing routes such as production of low cost parts and in-situ reduction of the ore during processing. Design/methodology/approach Blown powder directed energy deposition was used as the processing method. The process was observed through high-speed imaging, and computed tomography was used to analyse the specimens. Findings The experimental trials give preliminary results showing potential for the processability of iron ore for additive manufacturing. A large and stable melt pool is formed in spite of the inhomogeneous material used. Single and multilayer tracks could be deposited. Although smooth and even on the surface, the single layer tracks displayed porosity. In case of multilayered tracks, delamination from the substrate material and deformation can be seen. High-speed videos of the process reveal various process phenomena such as melting of ore powder during feeding, cloud formation, melt pool size, melt flow and spatter formation. Originality/value Very little literature is available that studies the possible use of ore in additive manufacturing. Although the process studied here is not industrially useable as is, it is a step towards processing cheap unprocessed material with a laser beam.

Effect of depositing torch angle on the first layer of wire arc additive manufacture using cold metal transfer (CMT)

2019 ◽  
Vol 46 (2) ◽  
pp. 259-266 ◽  
Author(s):  
Chuanchu Su ◽  
Xizhang Chen
Keyword(s):  
Weld Pool ◽  
High Speed ◽  
Additive Manufacture ◽  
High Speed Camera ◽  
Porosity Formation ◽  
Cold Metal Transfer ◽  
Content Type ◽  
Deposition Direction ◽  
Cold Metal ◽  
Torch Angle

Purpose This paper aims to mainly report the impact of torch angle on the dynamic behavior of the weld pool which is recorded and monitored in real time with the aid of a high-speed camera system. The influence of depositing torch angle on the fluctuation behavior of weld pool and the quality of weld formation are compared and analyzed. Design/methodology/approach The FANUC controlled robotic manufacturing system comprised a Fronius cold metal transfer (CMT) Advanced 4000R power source, FANUC robot, water cooling system, wire feeding system and a gas shielding system. An infrared laser was used to illuminate the weld pool for high-speed imaging at 1,000 frames per second with CR600X2 high-speed camera. The high-speed camera was set up a 35 ° angle with the deposition direction to investigate the weld pool flow patterns derived from high-speed video and the effect of torch angles on the first layer of wire additive manufacture-CMT. Findings The experimental results demonstrated that different torch angles significantly influence on the deposited morphology, porosity formation rate and weld pool flow. Originality/value With regard to the first layer of wire arc additive manufacture of aluminum alloys, the change of torch angle is critical. It is clear that different torch angles significantly influence on the weld morphology, porosity formation and weld pool flow. Furthermore, under different torch angles, the deposited beads will produce different defects. To get well deposited beads, 0-10° torch could be made away from the vertical position of the deposition direction, in which the formation of deposited beads were well and less porosity and other defects.

Effect of path strategy on residual stress and distortion in laser and cold metal transfer hybrid additive manufacturing

2021 ◽  
pp. 102203
Author(s):  
Runsheng Li ◽  
Guilan Wang ◽  
Xushan Zhao ◽  
Fusheng Dai ◽  
Cheng Huang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Metal Transfer ◽  
Cold Metal Transfer ◽  
Cold Metal

scholarly journals Effect of Filler Metal Type on Microstructure and Mechanical Properties of Fabricated NiAl Bronze Alloy Using Wire Arc Additive Manufacturing System

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 513
Author(s):  
Jae Won Kim ◽  
Jae-Deuk Kim ◽  
Jooyoung Cheon ◽  
Changwook Ji
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Metal Wire ◽  
Cold Metal Transfer ◽  
Metal Type ◽  
Cold Metal ◽  
Wire Arc Additive Manufacturing

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κIII structure with β´ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κIII structure in between.

Effect of the CMT advanced process combined with an active cooling technique on macro and microstructural aspects of aluminum WAAM

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Felipe Ribeiro Teixeira ◽  
Fernando Matos Scotti ◽  
Ruham Pablo Reis ◽  
Américo Scotti
Keyword(s):  
Electrical Signal ◽  
Management Technique ◽  
Marginal Effect ◽  
Thin Wall ◽  
Cold Metal Transfer ◽  
Content Type ◽  
Active Cooling ◽  
Cold Metal ◽  
Wire Arc Additive Manufacturing ◽  
Cooling Technique

Purpose This paper aims to assess the combined effect of the Cold Metal Transfer (CMT) advanced process and of a thermal management technique (near immersion active cooling [NIAC]) on the macro and microstructure of Al wall-like preforms built by wire arc additive manufacturing (WAAM). As specific objective, it sought to provide information on the effects of the electrode-positive/electrode-negative (EP/EN) parameter in the CMT advanced process fundamental characteristics. Design/methodology/approach Initially, bead-on-plate deposits were produced with different EP/EN ratios, still keeping the same deposition rate, and the outcomes on the electrical signal traces and bead formation were analyzed. In a second stage, the EP/EN parameter and the layer edge to water distance (LEWD) parameter from the NIAC technique were systematically varied and the resultant macro and microstructures compared with those formed by applying natural cooling. Findings Constraints of EP/EN setting range were uncovered and discussed. The use of the NIAC technique favors the formation of finer grains. For a given EP/EN value, a variation in the NIAC intensity (LEWD value) showed marginal effect on grain size. When the EP/EN parameter effect is isolated, i.e. for a given LEWD setting, it was observed that an increase in the EP/EN level favors coarser grains. Originality/value Both the EP/EN parameter and the use of an active cooling technique (NIAC) might be used, even in combination, as effective tools for achieving proper macro and microstructure in WAAM of thin wall builds.

Multiaxis wire and arc additive manufacturing for overhangs based on conical substrates

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fusheng Dai ◽  
Shuaifeng Zhang ◽  
Runsheng Li ◽  
Haiou Zhang
Keyword(s):  
Principal Component Analysis ◽  
Additive Manufacturing ◽  
Design Methodology ◽  
Principal Component ◽  
Deposition Process ◽  
Content Type ◽  
Melt Pool ◽  
Planning Approach ◽  
Intelligent Approach ◽  
Supporting Structures

Purpose This paper aims to present a series of approaches for three-related issues in multiaxis in wire and arc additive manufacturing (WAAM) as follows: how to achieve a stable and robust deposition process and maintain uniform growth of the part; how to maintain consistent formation of a melt pool on the surface of the workpiece; and how to fabricate an overhanging structure without supports. Design/methodology/approach The principal component analysis-based path planning approach is proposed to compute the best scanning directions of slicing contours for the generation of filling paths, including zigzag paths and parallel skeleton paths. These printing paths have been experimented with in WAAM. To maintain consistent formation of a melt pool at overhanging regions, the authors introduce definitions for the overhanging point, overhanging distance and overhanging vector, with which the authors can compute and optimize the multiaxis motion. A novel fabricating strategy of depositing the overhanging segments as a support for the deposition of filling paths is presented. Findings The second principal component of a planar contour is a reasonable scanning direction to generate zigzag filling paths and parallel skeleton filling paths. The overhanging regions of a printing layer can be supported by pre-deposition of overhanging segments. Large overhangs can be successfully fabricated by the multiaxis WAAM process without supporting structures. Originality/value An intelligent approach of generating zigzag printing paths and parallel skeleton printing paths. Optimizations of depositing zigzag paths and parallel skeleton paths. Applications of overhanging point overhanging distance and overhanging vector for multiaxis motion planning. A novel fabricating strategy of depositing the overhanging segments as a support for the deposition of filling paths.

scholarly journals In-situ characterization of laser-powder interaction and cooling rates through high-speed imaging of powder bed fusion additive manufacturing

2017 ◽  
Vol 135 ◽  
pp. 385-396 ◽  
Author(s):  
Umberto Scipioni Bertoli ◽  
Gabe Guss ◽  
Sheldon Wu ◽  
Manyalibo J. Matthews ◽  
Julie M. Schoenung
Keyword(s):  
Additive Manufacturing ◽  
High Speed ◽  
Powder Bed Fusion ◽  
In Situ Characterization ◽  
High Speed Imaging ◽  
Cooling Rates ◽  
Powder Bed

scholarly journals Wire and Arc Additive Manufacturing of High-Strength Al–Zn–Mg Aluminum Alloy

2021 ◽  
Vol 8 ◽  
Author(s):  
Xuewei Fang ◽  
Guopeng Chen ◽  
Jiannan Yang ◽  
Yang Xie ◽  
Ke Huang ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Aluminum Alloys ◽  
Electron Backscatter Diffraction ◽  
Vertical Direction ◽  
High Strength ◽  
Thin Wall ◽  
Cold Metal Transfer ◽  
X Ray ◽  
Manufacturing Techniques ◽  
Cold Metal

High-strength 7xxx series aluminum alloys are of great importance for the aerospace industries. However, this type of aluminum alloys has poor processability for most additive manufacturing techniques. In this paper, a newly designed Al–Zn–Mg alloy was used as a feeding wire to fabricate thin wall-shaped samples using the wire and arc additive manufacturing (WAAM) technique. These samples were fabricated based on the cold metal transfer (CMT) process with four different types of arc modes, that is, CMT, CMT-incorporated pulse (CMT + P), CMT-incorporated polarity (CMT + A), CMT-incorporated pulse and polarity (CMT + PA). The optical microscopy, x-ray computed tomography, and scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) were employed to characterize the microstructure and phase constitution. The results clearly reveal that the porosity varies with the arc modes, and the densest sample with porosity of 0.97% was obtained using the CMT + P mode. The mechanical properties of the fabricated samples are also dependent on the arc modes. The tensile strength and yield strength of the sample manufactured by the CMT + PA arc mode are the highest. In terms of anisotropy, the strength differences in horizontal and vertical direction of the samples made by CMT + PA, CMT + A, and CMT modes are all large, which is mainly ascribed to the pores distributed at the interlayer region.

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