scholarly journals Down-facing surfaces in laser powder bed fusion of Ti6Al4V: Effect of dross formation on dimensional accuracy and surface texture

2021 ◽  
pp. 102148
Author(s):  
Amal Charles ◽  
Ahmed Elkaseer ◽  
Umberto Paggi ◽  
Lore Thijs ◽  
Veit Hagenmeyer ◽  
...  
Keyword(s):  
Surface Texture ◽  
Dimensional Accuracy ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Dross Formation

On the manufacturability of Inconel 718 thin-walled honeycomb structures by laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
José M. Zea Pérez ◽  
Jorge Corona-Castuera ◽  
Carlos Poblano-Salas ◽  
John Henao ◽  
Arturo Hernández Hernández
Keyword(s):  
Mechanical Properties ◽  
Inconel 718 ◽  
Dimensional Accuracy ◽  
Honeycomb Lattice ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Content Type ◽  
Powder Bed ◽  
Thin Walled

Purpose The purpose of this paper is to study the effects of printing strategies and processing parameters on wall thickness, microhardness and compression strength of Inconel 718 superalloy thin-walled honeycomb lattice structures manufactured by laser powder bed fusion (L-PBF). Design/methodology/approach Two printing contour strategies were applied for producing thin-walled honeycomb lattice structures in which the laser power, contour path, scanning speed and beam offset were systematically modified. The specimens were analyzed by optical microscopy for dimensional accuracy. Vickers hardness and quasi-static uniaxial compression tests were performed on the specimens with the least difference between the design wall thickness and the as built one to evaluate their mechanical properties and compare them with the counterparts obtained by using standard print strategies. Findings The contour printing strategies and process parameters have a significant influence on reducing the fabrication time of thin-walled honeycomb lattice structures (up to 50%) and can lead to improve the manufacturability and dimensional accuracy. Also, an increase in the young modulus up to 0.8 times and improvement in the energy absorption up to 48% with respect to those produced by following a standard strategy was observed. Originality/value This study showed that printing contour strategies can be used for faster fabrication of thin-walled lattice honeycomb structures with similar mechanical properties than those obtained by using a default printing strategy.

scholarly journals The Dimensional Accuracy of Thin-Walled Parts Manufactured by Laser-Powder Bed Fusion Process

2020 ◽  
Vol 4 (3) ◽  
pp. 91
Author(s):  
Josef Tomas ◽  
Leonhard Hitzler ◽  
Marco Köller ◽  
Jonas von Kobylinski ◽  
Michael Sedlmajer ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Dimensional Accuracy ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Cooling Channels ◽  
Thin Walled ◽  
Scanning Strategies ◽  
Different Diameters ◽  
Functional Components

Laser-Powder Bed Fusion brings new possibilities for the design of parts, e.g., cutter shafts with integrated cooling channels close to the contour. However, there are new challenges to dimensional accuracy in the production of thin-walled components, e.g., heat exchangers. High degrees of dimensional accuracy are necessary for the production of functional components. The aim is to already achieve these during the process, to reduce post-processing costs and time. In this work, thin-walled ring specimens of H13 tool steel are produced and used for the analysis of dimensional accuracy and residual stresses. Two different scanning strategies were evaluated. One is a stripe scan strategy, which was automatically generated and provided by the machine manufacturer, and a (manually designed) sectional scan strategy. The ring segment strategy is designed by manually segmenting the geometry, which results in a longer preparation time. The samples were printed in different diameters and analyzed with respect to the degree of accuracy and residual stresses. The dimensional accuracy of ring specimens could be improved by up to 81% with the introduced sectional strategy compared to the standard approach.

scholarly journals Variation of Surface Topography in Laser Powder Bed Fusion Additive Manufacturing of Nickel Super Alloy 625

2019 ◽  
Vol 124 ◽  
Author(s):  
Jason C. Fox
Keyword(s):  
Additive Manufacturing ◽  
Surface Topography ◽  
Surface Texture ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Alloy 625 ◽  
Data Files ◽  
Height Data ◽  
Super Alloy

This document provides details on the files available for download in the dataset "Variation of Surface Texture in Laser Powder Bed Fusion of Nickel Super Alloy 625." The following sections provide details on the experiments, methods, and data files. The experiment detailed in this document methodically varies part position and surface orientation relative to the build plate and relative to the recoater blade. This dataset provides surface height data for analysis and development of correlations by the greater research.

scholarly journals Laser Powder Bed Fusion of a Topology Optimized and Surface Textured Rudder Bulb with Lightweight and Drag-Reducing Design

2021 ◽  
Vol 9 (9) ◽  
pp. 1032
Author(s):  
Alessandro Scarpellini ◽  
Valentina Finazzi ◽  
Paolo Schito ◽  
Arianna Bionda ◽  
Andrea Ratti ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Surface Texture ◽  
Topological Optimization ◽  
Hydrodynamic Resistance ◽  
Stream Velocity ◽  
Fish Scale ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
European Sea Bass ◽  
Powder Bed

This work demonstrates the advantages of using laser powder bed fusion for producing a rudder bulb of a moth class sailing racing boat via laser powder bed fusion (LPBF). The component was designed to reduce weight using an AlSi7Mg0.6 alloy and incorporated a biomimetic surface texture for drag reduction. For the topological optimization, the component was loaded structurally due to foil wing’s lift action as well as from the environment due to hydrodynamic resistance. The aim was to minimize core mass while preserving stiffness and the second to benefit from drag reduction capability in terms of passive surface behavior. The external surface texture is inspired by scales of the European sea bass. Both these features were embedded to the component and produced by LPBF in a single run, with the required resolution. Drag reduction was estimated in the order of for free stream velocity of . The production of the final part resulted in limited geometrical error with respect to scales 3D model, with the desired mechanical properties. A reduction in weight of approximately with respect to original full solid model from 452 to 190 g was achieved thanks to core topology optimization. Sandblasting was adopted as finishing technique since it was able to improve surface quality while preserving fish scale geometries. The feasibility of producing the biomimetic surfaces and the weight reduction were validated with the produced full-sized component.

Verzug bei pulverbettbasiertem Schmelzen von TiAl6V4/Distortion in laser beam melting – Influences of part geometry and heat treatment

2021 ◽  
Vol 111 (06) ◽  
pp. 372-377
Author(s):  
Andreas Hofmann ◽  
Alexander Mahr ◽  
Frank Döpper ◽  
Christian Bay
Keyword(s):  
Heat Treatment ◽  
Energy Input ◽  
Dimensional Accuracy ◽  
Temperature Gradients ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Thermally Induced ◽  
Powder Bed ◽  
Part Geometry ◽  
Laser Beam Melting

Der hohe lokale Energieeintrag beim pulverbettbasierten Schmelzen mittels Laserstrahl (laser powder bed fusion, LPBF) bewirkt hohe Temperaturgradienten. Dies führt zu thermisch induzierten Eigenspannungen und Verzug in den gefertigten Bauteilen, wodurch deren Form- und Maßhaltigkeit negativ beeinträchtigt wird. In diesem Beitrag wird der Einfluss der Bauteilgeometrie und einer der Fertigung nachgelagerten Wärmebehandlung auf den Verzug von mittels LPBF gefertigten Bauteilen aus dem Werkstoff TiAl6V4 untersucht.   A high local energy input during laser powder bed fusion (LPBF) creates high temperature gradients. This leads to thermally induced residual stresses and distortion, which negatively affect the dimensional accuracy of components. This paperinvestigates the influence of component geometry and heat treatment after the manufacturing process on the distortion of components made by LPBF of TiAl6V4.

Experimental investigation on the effect of laser powder bed fusion process variables on dimensional accuracy, surface roughness and cylindricity of the AlSi10Mg alloy component

2021 ◽  
pp. 095440892110390
Author(s):  
Nagendra K Maurya ◽  
Ashish K Srivastava ◽  
Ambuj Saxena ◽  
Shashi P Dwivedi ◽  
Mashood Ashraf Ali ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Linear Dimension ◽  
Dimensional Accuracy ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Process Variables ◽  
Connecting Rod ◽  
Powder Bed ◽  
Response Variables

The present study deals with the influence of laser powder bed fusion process parameters on the selected linear dimension, surface roughness and cylindricity of AlSi10Mg alloy for manufacturing of a prototype connecting rod. The process variables used in this investigation are laser power, laser velocity, layer thickness and scanning speed. Response surface methodology is used to perform experiments and data analysis. The levels of process parameters are same that is, five for all the selected input process variables. An automotive component connecting rod is used as a component to analyze the effect of process variables on selected response variables. The optimum sating of process variables are different for dimensional accuracy, surface roughness and cylindricity. Minitab 14 software is used for the data analysis. The international tolerance grades of confirmation experiments are calculated as per the ISO standard UNI EN 20286-I and DIN 16901. A quadratic regression models are developed to estimate the response variables in terms of process parameters. The model is adequate within the experimental domain. X-chart of confirmation experiments is plotted. The deviation in the linear dimension is within the limit of ±3 sigma (σ). The lowest values of response variables at the best level of process parameters are obtained, that is, percentage error in dimensional accuracy of 2.65%, surface roughness of 2.57 µm and cylindricity of 0.09 mm. The novelty of this work lies in the fact that only a few studies have been conducted related to the form errors in the archival literature.

Focus Variation Measurement and Prediction of Surface Texture Parameters Using Machine Learning in Laser Powder Bed Fusion

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Tuğrul Özel ◽  
Ayça Altay ◽  
Bilgin Kaftanoğlu ◽  
Richard Leach ◽  
Nicola Senin ◽  
...  
Keyword(s):  
Machine Learning ◽  
Energy Density ◽  
Surface Topography ◽  
Process Parameters ◽  
Surface Texture ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Texture Parameters ◽  
Focus Variation

Abstract The powder bed fusion-based additive manufacturing process uses a laser to melt and fuse powder metal material together and creates parts with intricate surface topography that are often influenced by laser path, layer-to-layer scanning strategies, and energy density. Surface topography investigations of as-built, nickel alloy (625) surfaces were performed by obtaining areal height maps using focus variation microscopy for samples produced at various energy density settings and two different scan strategies. Surface areal height maps and measured surface texture parameters revealed the highly irregular nature of surface topography created by laser powder bed fusion (LPBF). Effects of process parameters and energy density on the areal surface texture have been identified. Machine learning methods were applied to measured data to establish input and output relationships between process parameters and measured surface texture parameters with predictive capabilities. The advantages of utilizing such predictive models for process planning purposes are highlighted.

scholarly journals Melting Cell Based Compensated Design Method for Improving Dimensional Accuracy of Additively Manufactured Thin Channels

2021 ◽  
Author(s):  
Li Sun ◽  
Xiaobo Ren ◽  
Jianying He ◽  
Zhiliang Zhang
Keyword(s):  
Design Method ◽  
Dimensional Accuracy ◽  
Geometric Error ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Dimensional Deviation ◽  
Dross Formation ◽  
Complicated Geometry ◽  
Geometrical Relationship ◽  
Remarkable Agreement

AbstractPowder-bed fusion additive manufacturing technology makes it possible to produce parts with complicated geometry and high accuracy. However, dimensional deviation caused by powder overmelting and dross formation is still a challenge for manufacturing thin channels. In this study, the origins of the overmelting of printed thin channels were analyzed and a concept called “melting cell” is proposed to describe and quantify the geometric error. Based on the geometrical relationship between the melting cell and target channel, a method for predicting and optimizing the final geometry of thin channels is outlined. In order to verify the method, geometries of thin horizontal circular channels in various sizes are studied as examples. The predicted results by the proposed method show a remarkable agreement with available experimental results. Moreover, a new egg-shaped compensated design, which is able to improve the dimensional accuracy of thin horizontal circular channels, is presented. The proposed method is simple yet very effective. It can be easily extended to the manufacturing of thin channels with various shapes, materials, and different powder bed fusion processes.

scholarly journals Characterization, mechanical properties and dimensional accuracy of a Zr-based bulk metallic glass manufactured via laser powder-bed fusion

2021 ◽  
Vol 199 ◽  
pp. 109400
Author(s):  
Navid Sohrabi ◽  
Jamasp Jhabvala ◽  
Güven Kurtuldu ◽  
Mihai Stoica ◽  
Annapaola Parrilli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Dimensional Accuracy ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed
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