Porosity content control of CoCrMo and titanium parts by Taguchi method applied to selective laser melting process parameter

2016 ◽  
Vol 22 (1) ◽  
pp. 20-30 ◽  
Author(s):  
David Joguet ◽  
Sophie Costil ◽  
Hanlin Liao ◽  
Yoann Danlos
Keyword(s):  
Selective Laser Melting ◽  
Design Methodology ◽  
Melting Process ◽  
Research Approach ◽  
Analysis Method ◽  
Laser Melting ◽  
Huge Number ◽  
Energy Estimation ◽  
Content Type ◽  
Potential Applications

Purpose – The purpose of this paper consists in the optimization and understanding of the Selective Laser Melting (SLM) manufacturing process of biomaterials, such as T40 and CoCrMo, as scaffolds. Moreover, process optimization is also challenging, with regards to the huge number of parameters and their influence on the finished product. Design/methodology/approach – The paper opted for an exploratory study using Taguchi analysis method to precisely identify the most relevant parameters and justify the energy estimation. Findings – The study showed that SLM fits perfectly with the T40 and CoCrMo part manufacturing. This method allowed to have a complete overview of all the potential applications of SLM for implant manufacturing. Originality/value – With this research approach, the results may be generalized to other material and showed a good theoretical approach.

scholarly journals Selective laser melting of Ti6Al7Nb with hydroxyapatite addition

2014 ◽  
Vol 20 (4) ◽  
pp. 301-310 ◽  
Author(s):  
Teodora Marcu ◽  
Cinzia Menapace ◽  
Luca Girardini ◽  
Dan Leordean ◽  
Catalin Popa
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Design Methodology ◽  
Point Of View ◽  
Medical Applications ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Content Type ◽  
Processing Times ◽  
Scanning Electron

Purpose – The purpose of this paper was to obtain by means of selective laser melting and then characterize biocomposites of medical-grade Ti6Al7Nb with hydroxyapatite (2 and 5 vol.%) and without hydroxyapatite, as reference. Design/methodology/approach – Rectangular samples were manufactured with the same scanning strategy; the laser power was between 50 W and 200 W. Processed samples were analysed by means of optical microscopy, scanning electron microscopy and microhardness. Findings – The results showed that despite the very short processing times, hydroxyapatite decomposed and interacted with the base Ti6Al7Nb material. The decomposition degree was found to depend on the applied laser power. From the porosity and bulk microstructure point of view, the most appropriate materials for the purposed medical applications were Ti6Al7Nb with hydroxyapatite processed with a laser power of 50 W. Originality/value – The originality of the present work consists in the study of the behaviour and interaction of hydroxyapatite additive with the Ti6Al7Nb base powder under selective laser melting conditions, as depending on the applied laser power.

Analytic and numeric solutions for stagnation-point flow with melting, thermal-diffusion and diffusion-thermo effects

2014 ◽  
Vol 24 (2) ◽  
pp. 438-454 ◽  
Author(s):  
M. Awais ◽  
T. Hayat ◽  
M. Mustafa ◽  
K. Bhattacharyya ◽  
M. Asif Farooq
Keyword(s):  
Thermal Diffusion ◽  
Design Methodology ◽  
Linear Problem ◽  
Melting Process ◽  
Surface Heat ◽  
Combined Effects ◽  
Analysis Method ◽  
Content Type ◽  
Homotopy Analysis ◽  
And Diffusion

Purpose – The aim of this work is to analyze the combined effects of melting, thermal-diffusion and diffusion-thermo on the flow of non-Newtonian fluid. Design/methodology/approach – An efficient approach namely homotopy analysis method is applied to compute the solution of the non-linear problem. Moreover, numerical results using MATLAB function bvp4c are also computed. Findings – Main findings are an increase in the melting process corresponding to increase in the velocity and the boundary layer thickness. However, surface heat and mass transfer decrease by increasing the values of melting parameter M. Originality/value – Combined effects of thermal-diffusion and diffusion-thermo are analyzed and the solutions are computed both numerically and analytically. Some deduced results can be obtained in a limiting sense.

Simultaneous extraction of profile and surface roughness of 3D SLM components using fringe projection method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Terry Yuan-Fang Chen ◽  
Yu-Lung Lo ◽  
Ze-Hong Lin ◽  
Jui-Yu Lin
Keyword(s):  
Surface Roughness ◽  
Metal Powder ◽  
Design Methodology ◽  
Melting Process ◽  
Phase Unwrapping ◽  
Fringe Projection ◽  
Laser Melting ◽  
Height Difference ◽  
Content Type ◽  
Detection Technology

Purpose The purpose of this study was expected to simultaneously monitor the surface roughness of each solidified layer, the surface roughness of the metal powder, the outline of the solidified layer, and the height difference between the solidified layer and the metal powder. Design/methodology/approach In the proposed approach, color images with red, green and blue fringes are used to measure the shape of the built object using a three-step phase-shift algorithm and phase-unwrapping method. In addition, the surface roughness is extracted from the speckle information in the captured image using a predetermined autocorrelation function. Findings The feasibility and accuracy of the proposed system were validated by comparing it with a commercial system for an identical set of samples fabricated by a selective laser melting process. The maximum and minimum errors between the two systems are approximately 24% and 0.8%, respectively. Originality/value In the additive manufacturing field, the authors are the first to use fringe detection technology to simultaneously measure the profile of the printed layer and its surface roughness.

Investigation of selective laser melting process for Cu-5Sn alloy on surface roughness, microstructure and mechanical property

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Peng Yang ◽  
Dingyong He ◽  
Zengjie Wang ◽  
Zhen Tan ◽  
Hanguang Fu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Surface Roughness ◽  
Selective Laser Melting ◽  
High Strength ◽  
Melting Process ◽  
Scanning Speed ◽  
Laser Melting ◽  
Forming Process ◽  
Content Type

Purpose In this research, the highly dense bulk Cu-5Sn alloy specimens were fabricated using selective laser melting (SLM). This study aims to establish the relationship between laser power (LP), scanning speed (SS) and hatch space (HS) with surface roughness (Ra) and density. To obtain Cu-5Sn alloy formed parts with high strength and low surface roughness. The microstructure and mechanical properties of SLMed Cu-5Sn were investigated. Design/methodology/approach The relative density (RD) was optimized using the response surface method (RSM) and analysis of variance. First, the Ra of SLMed formed specimens was studied to optimize the forming process parameters with a good surface. Then, the dense specimens were studied by ANOVA and the RSM to obtain dense specimens for mechanical property analysis. Findings Dense specimens were obtained by RSM and ANOVA. The tensile properties were compared with the casted specimens. The yield and ultimate strengths increased from 71 and 131 MPa for the cast specimens to 334 and 489 MPa for the SLMed specimens, respectively. The ductility increased significantly from 11% to 23%, due to the refined microstructure of the SLMed specimens, as well as the formation of many twin crystals. Originality/value The Ra, RD and mechanical properties of SLM specimens Cu-5Sn were systematically studied, and the influencing factors were analyzed together. This study provides a theoretical and practical example to improve the surface quality and RD.

Manufacturability analysis of extremely fine porous structures for selective laser melting process of Ti6Al4V alloy

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liping Ding ◽  
Shujie Tan ◽  
Wenliang Chen ◽  
Yaming Jin ◽  
Yicha Zhang
Keyword(s):  
Porous Structure ◽  
Selective Laser Melting ◽  
Industrial Application ◽  
Geometric Modeling ◽  
Evaluation Method ◽  
Stable Process ◽  
Melting Process ◽  
Porous Structures ◽  
Laser Melting ◽  
Content Type

Purpose The manufacturability of extremely fine porous structures in the SLM process has rarely been investigated, leading to unpredicted manufacturing results and preventing steady medical or industrial application. The research objective is to find out the process limitation and key processing parameters for printing fine porous structures so as to give reference for design and manufacturing planning. Design/methodology/approach In metallic AM processes, the difficulty of geometric modeling and manufacturing of structures with pore sizes less than 350 μm exists. The manufacturability of porous structures in selective laser melting (SLM) has rarely been investigated, leading to unpredicted manufacturing results and preventing steady medical or industrial application. To solve this problem, a comprehensive experimental study was conducted to benchmark the manufacturability of the SLM process for extremely fine porous structures (less than 350 um and near a limitation of 100 um) and propose a manufacturing result evaluation method. Numerous porous structure samples were printed to help collect critical datasets for manufacturability analysis. Findings The results show that the SLM process can achieve an extreme fine feature with a diameter of 90 μm in stable process control, and the process parameters with their control strategies as well as the printing process planning have an important impact on the printing results. A statistical analysis reveals the implicit complex relations between the porous structure geometries and the SLM process parameter settings. Originality/value It is the first time to investigate the manufacturability of extremely fine porous structures of SLM. The method for manufacturability analysis and printing parameter control of fine porous structure are discussed.

Effect of preheat and layer thickness on selective laser melting (SLM) of magnesium

2016 ◽  
Vol 22 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Monica Mahesh Savalani ◽  
Jorge Martinez Pizarro
Keyword(s):  
Layer Thickness ◽  
Selective Laser Melting ◽  
Design Methodology ◽  
High Surface ◽  
Pulse Mode ◽  
Laser Melting ◽  
Content Type ◽  
New Generation ◽  
Electronic Microscope ◽  
Quality Surface

Purpose – The purpose of this paper is to investigate the effect of preheat and layer thickness in selective laser melting (SLM) of magnesium using pulse mode. Magnesium has been considered as a new generation of implant materials which are bioactive and biodegradable for orthopaedic applications. Design/methodology/approach – To produce optimal single magnesium tracks to compare the effect of layer thickness and preheat, different laser parameters were investigated. The analysis was made based on digital and electronic microscope images and mechanical measurements. Findings – Improvements in the magnesium tracks due to preheating were successfully achieved. The analysis shows better bonding to the surface. The preheated tracks present an improvement in quality surface: smoother and flatter surfaces are discovered for the low layer thicknesses. When the thickness increases, the surface was disrupted and presented high surface roughness values. These were attributed to the Marangoni convection. Originality/value – This study continues valuing the fabrication of magnesium with SLM. It shows the improvements of preheat and effect of different layer thicknesses on the part properties.

Friction and wear of the intervertebral disc endoprosthesis manufactured with use of selective laser melting process

2017 ◽  
Vol 23 (6) ◽  
pp. 1032-1042 ◽  
Author(s):  
Adrian Bartlomiej Mróz ◽  
Lukasz Lapaj ◽  
Tomasz Wisniewski ◽  
Konstanty Skalski ◽  
Volf Leshchynsky
Keyword(s):  
Reference Material ◽  
Intervertebral Disc ◽  
Selective Laser Melting ◽  
Friction And Wear ◽  
Melting Process ◽  
Wear Behaviour ◽  
Laser Melting ◽  
Content Type ◽  
Selective Laser Melting Process ◽  
Astm F75

Purpose Orthopaedic implants, such as intervertebral disc endoprostheses (IDEs) are difficult to manufacture by means of conventional methods because of their complex shape. However, technologies developed in recent years, such as selective laser melting, could simplify this process. Although this method is attractive in both manufacturing and rapid prototyping of IDEs, little is known about their tribological performance. The functional aim of the work is to conduct a tribological evaluation of the ASTM F75 alloy after selective laser melting process and to investigate the viability of the technology in IDE design. The research aim was an explanation of the wear mechanism of bearing surfaces with respect to the reference material. Design/methodology/approach In this paper, the tribological test results of a lumbar IDE prototype fabricated by selective laser melting and forging is presented and compared. The endoprostheses were fabricated from commercially available ASTM F75 powder using a selective laser melting device. As a reference material, a forged ASTM F1537 LC alloy was used. Comparative wear and friction tests were carried out with the use of a unique spine simulator. Findings The obtained results confirm the viability of the selective laser technology in endoprosthesis design. Unfortunately, poorer tribological wear resistance of endoprostheses produced by means of selective laser melting (SLM) technology compared with that of the reference material calls into question the possibility of using these technologies in the manufacturing process of endoprosthesis' components exposed to tribological wear. Originality/value This paper presents the friction and wear behaviour of the lumbar IDE prototype. The tests were carried out in motion and loading conditions close to those we observe in the lumbar spine.

Research on the microstructure and properties of the overhanging structure formed by selective laser melting

2017 ◽  
Vol 23 (5) ◽  
pp. 904-910 ◽  
Author(s):  
Jianfeng Sun ◽  
Zhou Yang ◽  
Yongqiang Yang ◽  
Di Wang
Keyword(s):  
Selective Laser Melting ◽  
Design Methodology ◽  
Basic Data ◽  
Theoretical Studies ◽  
Laser Melting ◽  
Content Type ◽  
Structure Matrix ◽  
Microstructure And Properties ◽  
The Future ◽  
The Matrix

Purpose This paper aims to analyze the different between matrix and overhanging structure and indicate the laws and mechanism of overhanging structure formed by selective laser melting (SLM). Design/methodology/approach This paper includes processing the matrix and overhanging structure with optimized parameters and analyzing the microstructure and properties of matrix and overhanging with OM, SEM, XRD etc. so as to analyze and reveal the laws and mechanism of overhanging structure formed by SLM. Findings The solidification of overhanging structure begins from the structure’s edge and extends to its center; the distribution of the Cr with a diameter of 250 nm in the Fe matrix is uniform; the grain in the overhanging structure is growing faster than the grain in the matrix. The overhanging structure mainly composed by austenite has no apparent layer. Moreover, the microhardness of the overhanging structure is 258.6-294.0 Hv0.3, smaller than the microhardness of the matrix which is 236.4-300.9 Hv0.3. Originality/value This paper clarifies how to manufacture overhanging structure and non-overhanging structure matrix with optimized parameters, analyzes the microstructures and compares the properties of both overhanging structure and non-overhanging structure “matrix”, so as to analyze the reasons for the forming of the overhanging structure, which in turn lauds basic data foundation for the theoretical studies in the future.

Characteristic length of the solidified melt pool in selective laser melting process

2017 ◽  
Vol 23 (2) ◽  
pp. 370-381 ◽  
Author(s):  
Il Hyuk Ahn ◽  
Seung Ki Moon ◽  
Jihong Hwang ◽  
Guijun Bi
Keyword(s):  
Selective Laser Melting ◽  
Characteristic Length ◽  
Melting Process ◽  
Evaluation Methods ◽  
Laser Melting ◽  
Content Type ◽  
Selective Laser Melting Process ◽  
Melt Pool ◽  
Scan Modes ◽  
Hatch Spacing

Purpose This paper aims to propose methods to evaluate the characteristic length of the melt pool for accurate fabrication and to identify the optimal process parameters in the selective laser melting process. Design/methodology/approach Specimens with the types of the scans by controlling the degree of the overlap with hatch spacing are fabricated. The scan modes are classified by statistically analyzing the results of hardness tests. According to the classification of the scans, the evaluation methods are proposed based on the observation of the shape of the solidified melt pool. Findings The control of the hatch spacing can reproduce all modes of the scan conditions, and hardness can be used to classify the scan modes. Originality/value The proposed evaluation methods are based on the analysis of the experimental observation so that they can be easily used for the real evaluation.

scholarly journals Improving surface quality in selective laser melting based tool making

2021 ◽  
Author(s):  
Filippo Simoni ◽  
Andrea Huxol ◽  
Franz-Josef Villmer
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Laser Remelting ◽  
Laser Melting ◽  
Great Cost ◽  
Starting Point ◽  
Processing Techniques

AbstractIn the last years, Additive Manufacturing, thanks to its capability of continuous improvements in performance and cost-efficiency, was able to partly replace and redefine well-established manufacturing processes. This research is based on the idea to achieve great cost and operational benefits especially in the field of tool making for injection molding by combining traditional and additive manufacturing in one process chain. Special attention is given to the surface quality in terms of surface roughness and its optimization directly in the Selective Laser Melting process. This article presents the possibility for a remelting process of the SLM parts as a way to optimize the surfaces of the produced parts. The influence of laser remelting on the surface roughness of the parts is analyzed while varying machine parameters like laser power and scan settings. Laser remelting with optimized parameter settings considerably improves the surface quality of SLM parts and is a great starting point for further post-processing techniques, which require a low initial value of surface roughness.

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