Dimensional characteristics of Ti-6Al-4V thin-walled parts prepared by wire-based multi-laser additive manufacturing in vacuum

2019 ◽  
Vol 25 (5) ◽  
pp. 849-856 ◽  
Author(s):  
Farui Du ◽  
Jinqian Zhu ◽  
Xueping Ding ◽  
Qi Zhang ◽  
Honglin Ma ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Laser Power ◽  
Manufacturing Industry ◽  
Heat Dissipation ◽  
Cooling Time ◽  
Height Increment ◽  
Laser Additive Manufacturing ◽  
Layer Width ◽  
Content Type ◽  
Thin Walled

Purpose A wire-based additive manufacturing system works with high manufacturing efficiency and low dimensional precision. The purpose of this paper is to study the dimensional characteristics of Ti-6Al-4V thin-walled parts with wire-based multi-laser additive manufacturing in vacuum. Design/methodology/approach Wire-based multi-laser additive manufacturing was carried out to understand the effect brought from different parameters. The Ti-6Al-4V thin-walled parts were formed by different height increments, power inputs and inter-layer cooling times in vacuum. Findings The result shows that, with the number of layers increment, the layer width of thin-walled part increases gradually in the beginning and stabilizes soon afterward. Height increment, laser power and inter-layer cooling time could affect the energy input to the deposited bead and heat accumulation of thin-walled part. The layer width decreases, while the height increment increases. The increment of laser power could increase the layer width. And, the increment of inter-layer cooling time (more than 5 s) has little effect on the layer width. Originality/value The heat dissipation mode of thin-walled parts in vacuum and the influence of different parameters on layer width are explained in this paper. It provides a reference for further understanding and controlling dimension precision of Ti-6Al-4V thin-walled part with wire-based multi-laser additive manufacturing in vacuum. At the same time, it provides a reference for researches of dimensional characteristics in the additive manufacturing industry.

Numerical study of heat transfer characteristics in positional wire and arc additive manufacturing

2020 ◽  
Vol 26 (9) ◽  
pp. 1627-1635
Author(s):  
Dongqing Yang ◽  
Jun Xiong ◽  
Rong Li
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Additive Manufacturing ◽  
Temperature Distribution ◽  
Finite Element Model ◽  
Heat Dissipation ◽  
Element Model ◽  
Heat Transfer Characteristics ◽  
Content Type ◽  
Thin Walled

Purpose This paper aims to fabricate inclined thin-walled components using positional wire and arc additive manufacturing (WAAM) and investigate the heat transfer characteristics of inclined thin-walled parts via finite element analysis method. Design/methodology/approach An inclined thin-walled part is fabricated in gas metal arc (GMA)-based additive manufacturing using a positional deposition approach in which the torch is set to be inclined with respect to the substrate surface. A three-dimensional finite element model is established to simulate the thermal process of the inclined component based on a general Goldak double ellipsoidal heat source and a combined heat dissipation model. Verification tests are performed based on thermal cycles of locations on the substrate and the molten pool size. Findings The simulated results are in agreement with experimental tests. It is shown that the dwell time between two adjacent layers greatly influences the number of the re-melting layers. The temperature distribution on both sides of the substrate is asymmetric, and the temperature peaks and temperature gradients of points in the same distance from the first deposition layer are different. Along the deposition path, the temperature distribution of the previous layer has a significant influence on the heat dissipation condition of the next layer. Originality/value The established finite element model is helpful to simulate and understand the heat transfer process of geometrical thin-walled components in WAAM.

Quality detection of laser additive manufacturing process based on coaxial vision monitoring

Sensor Review ◽  
2019 ◽  
Vol 39 (4) ◽  
pp. 512-521 ◽  
Author(s):  
Bo Chen ◽  
Yongzhen Yao ◽  
Yuhua Huang ◽  
Wenkang Wang ◽  
Caiwang Tan ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Process Parameters ◽  
Molten Pool ◽  
Laser Power ◽  
Laser Additive Manufacturing ◽  
Content Type ◽  
Melt Pool ◽  
Forming Defects ◽  
The Relationship ◽  
Pool Area

Purpose This paper aims to explore the influences of different process parameters, including laser power, scanning speed, defocusing distance and scanning mode, on the shape features of molten pool and, based on the obtained relationship, realize the diagnosis of forming defects during the process. Design/methodology/approach Molten pool was captured on-line based on a coaxial CCD camera mounted on the welding head, then image processing algorithms were developed to obtain melt pool features that could reflect the forming status, and it suggested that the molten pool area was the most sensitive characteristic. The influence of the processing parameters such as laser power, traverse speed, powder feed rate, defocusing distance and the melt pool area was studied, and then the melt pool area was used as the characteristic to detect the forming defects during the cladding and additive manufacturing process. Findings The influences of different process parameters on molten pool area were explored. Based on the relationship, different types of defects were accurately detected through analyzing the relationship between the molten pool area and time. Originality/value The findings would be helpful for the quality control of laser additive manufacturing.

The microstructure and mechanical properties of deposited-IN625 by laser additive manufacturing

2017 ◽  
Vol 23 (6) ◽  
pp. 1119-1129 ◽  
Author(s):  
Lanlan Qin ◽  
Changjun Chen ◽  
Min Zhang ◽  
Kai Yan ◽  
Guangping Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Additive Manufacturing ◽  
Dendritic Morphology ◽  
Laves Phase ◽  
Micro Hardness ◽  
Laser Additive Manufacturing ◽  
Content Type ◽  
Annealing Temperatures

Purpose Laser additive manufacturing (LAM) technology based on powder bed has been used to manufacture complex geometrical components. In this study, IN625 superalloys were fabricated by high-power fiber laser without cracks, bounding errors or porosity. Meanwhile, the objectives of this paper are to systemically investigate the microstructures, micro-hardness and the precipitated Laves phase of deposited-IN625 under different annealing temperatures. Design/methodology/approach The effects of annealing temperatures on the microstructure, micro-hardness and the precipitated Laves phase were studied by optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), selected area electron diffraction (SAED), backscattered electron (BSE) imaging in the SEM and transmission electron microscopy (TEM), respectively. The thermal stability of the dendritic morphology about IN625 superalloys was investigated through annealing at temperatures range from 1,000°C to 1,200°C. Findings It is found that the microstructure of deposited-IN625 was typical dendrite structure. Besides, some Laves phase precipitated in the interdendritic region results in the segregation of niobium and molybdenum. The thermal stability indicate that the morphology of dendrite can be stable up to 1,000°C. With the annealing temperatures increasing from 1,000 to 1,200°C, the Laves phase partially dissolves into the γ-Ni matrix, and the morphology of the remaining Laves phase is changing from irregular shape to rod-like or block-like shape. Research limitations/implications The heat treatment used on the IN625 superalloys is helpful for knowing the evolution of microstructures and precipitated phases thermal stability and mechanical properties. Practical implications Due to the different kinds of application conditions, the original microstructure of the IN625 superalloys fabricated by LAM may not be ideal. So exploring the influence of annealing treatment on IN625 superalloys can bring theory basis and guidance for actual production. Originality/value This study continues valuing the fabrication of IN625 by LAM. It shows the effect of annealing temperatures on the shape, size and distribution of Laves phase and the microstructures of deposited-IN625 superalloys.

A numerical prediction of residual stress for a thin-walled part with geometrical features fabricated by GMA-based additive manufacturing

2019 ◽  
Vol 26 (2) ◽  
pp. 299-308
Author(s):  
Rong Li ◽  
Jun Xiong
Keyword(s):  
Residual Stress ◽  
Additive Manufacturing ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Stress Distributions ◽  
Content Type ◽  
Geometrical Features ◽  
Longitudinal Residual Stress ◽  
Thin Walled

Purpose An accurate prediction of process-induced residual stress is necessary to prevent large distortion and cracks in gas metal arc (GMA)-based additive manufactured parts, especially thin-walled parts. The purpose of this study is to present an investigation into predicting the residual stress distributions of a thin-walled component with geometrical features. Design/methodology/approach A coupled thermo-mechanical finite element model considering a general Goldak double ellipsoidal heat source is built for a thin-walled component with geometrical features. To confirm the accuracy of the model, corresponding experiments are performed using a positional deposition method in which the torch is tilted from the normal direction of the substrate. During the experiment, the thermal cycle curves of locations on the substrate are obtained by thermocouples. The residual stresses on the substrate and part are measured using X-ray diffraction. The validated model is used to investigate the thermal stress evolution and residual stress distributions of the substrate and part. Findings Decent agreements are achieved after comparing the experimental and simulated results. It is shown that the geometrical feature of the part gives rise to an asymmetrical transversal residual stress distribution on the substrate surface, while it has a minimal influence on the longitudinal residual stress distribution. The residual stress distributions of the part are spatially uneven. The longitudinal tensile residual stress is the prominent residual stress in the central area of the component. Large wall-growth tensile residual stresses, which may cause delamination, appear at both ends of the component and the substrate–component interfaces. Originality/value The predicted residual stress distributions of the thin-walled part with geometrical features are helpful to understand the influence of geometry on the thermo-mechanical behavior in GMA-based additive manufacturing.

Curved-layered material extrusion modeling for thin-walled parts by a 5-axis machine

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaojing Feng ◽  
Bin Cui ◽  
Yaxiong Liu ◽  
Lianggang Li ◽  
Xiaojun Shi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Additive Manufacturing ◽  
Layered Material ◽  
Bottom Surface ◽  
Motion Mechanism ◽  
Content Type ◽  
Material Extrusion ◽  
Thin Walled ◽  
Five Axis

Purpose The purpose of this paper is to solve the problems of poor mechanical properties, high surface roughness and waste support materials of thin-walled parts fabricated by flat-layered additive manufacturing process. Design/methodology/approach This paper proposes a curved-layered material extrusion modeling process with a five-axis motion mechanism. This process has advantages of the platform rotating, non-support printing and three-dimensional printing path. First, the authors present a curved-layered algorithm by offsetting the bottom surface into a series of conformal surfaces and a toolpath generation algorithm based on the geodesic distance field in each conformal surface. Second, they introduce a parallel five-axis printing machine consisting of a printing head fixed on a delta-type manipulator and a rotary platform on a spherical parallel machine. Findings Mechanical experiments show the failure force of the five-axis printed samples is 153% higher than that of the three-axis printed samples. Forming experiments show that the surface roughness significantly decreases from 42.09 to 18.31 µm, and in addition, the material consumption reduces by 42.90%. These data indicate the curved-layered algorithm and five-axis motion mechanism in this paper could effectively improve mechanical properties and the surface roughness of thin-walled parts, and realize non-support printing. These methods also have reference value for other additive manufacturing processes. Originality/value Previous researchers mostly focus on printing simple shapes such as arch or “T”-like shape. In contrast, this study sets out to explore the algorithm and benefits of modeling thin-walled parts by a five-axis machine. Several validated models would allow comparability in five-axis printing.

Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact

2019 ◽  
Vol 25 (2) ◽  
pp. 221-231
Author(s):  
Jason M. Weaver ◽  
T.J. Barton ◽  
John Linn ◽  
Derrik Jenkins ◽  
Michael P. Miles ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Industry ◽  
Optical Measurement ◽  
Dimensional Accuracy ◽  
Additive Process ◽  
Content Type ◽  
System A ◽  
Inclined Surfaces ◽  
Touch Probe ◽  
Metal Additive

Purpose The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry.

Laser Transmission Technology of Laser Additive Manufacturing

2013 ◽  
Vol 380-384 ◽  
pp. 4315-4318
Author(s):  
Kai Zhang ◽  
Xiao Feng Shang ◽  
Lei Wang
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Laser Power ◽  
Structure Design ◽  
Optical Path ◽  
Metal Component ◽  
Laser Additive Manufacturing ◽  
Generator System ◽  
Additive Manufacturing Technology ◽  
And Function

The laser additive manufacturing technology is a laser assisted direct metal manufacturing process. This process offers the ability to make a metal component directly from CAD drawings. The manufacturing equipment consists of some components. Among them, the laser transmission component plays an important role in the whole fabricating process. It provides the energy source to melt the metal powder, so it is necessary to develop the laser transmission technology. This technology is achieved primarily by laser generator system and optical path transmission system. The related structure design and function implementation prove that the laser transmission technology can generate desirable laser power at precise assigned position, and complete the manufacturing process with flying colors.

Foam additive manufacturing technology: main characteristics and experiments for hull mold manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Elodie Paquet ◽  
Alain Bernard ◽  
Benoit Furet ◽  
Sébastien Garnier ◽  
Sébastien Le Loch
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Manufacturing Process ◽  
Manufacturing Industry ◽  
Pressure Head ◽  
Manufacturing Technology ◽  
Cnc Machining ◽  
Numerical Control ◽  
Content Type ◽  
Additive Manufacturing Technology

Purpose The purpose of this paper is to present a novel methodology to produce a large boat hull with a foam additive manufacturing (FAM) process. To respond to shipping market needs, this new process is being developed. FAM technology is a conventional three-dimensional (3D) printing process whereby layers are deposited onto a high-pressure head mounted on a six-axis robotic arm. Traditionally, molds and masters are made with computer numerical control (CNC) machining or finished by hand. Handcrafting the molds is obviously time-consuming and labor-intensive, but even CNC machining can be challenging for parts with complex geometries and tight deadlines. Design/methodology/approach The proposed FAM technology focuses on the masters and molds, that are directly produced by 3D printing. This paper describes an additive manufacturing technology through which the operator can create a large part and its tools using the capacities of this new FAM technology. Findings The study shows a comparison carried out between the traditional manufacturing process and the additive manufacturing process, which is illustrated through an industrial case of application in the manufacturing industry. This work details the application of FAM technology to fabricate a 2.5 m boat hull mold and the results show the time and cost savings of FAM in the fabrication of large molds. Originality/value Finally, the advantages and drawbacks of the FAM technology are then discussed and novel features such as monitoring system and control to improve the accuracy of partly printed are highlighted.

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