Selective laser melting of polymers: influence of powder coating on mechanical part properties

2018 ◽  
Vol 38 (7) ◽  
pp. 667-674 ◽  
Author(s):  
Maximilian Drexler ◽  
Sandra Greiner ◽  
Matthias Lexow ◽  
Lydia Lanzl ◽  
Katrin Wudy ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Powder Coating ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Part Quality ◽  
Thermal Fields ◽  
Compaction Behavior ◽  
Processing Strategies ◽  
Force Impact ◽  
New Processing

Abstract For the derivation of part quality increasing process strategies, knowledge about interactions between sub-processes of selective laser melting (SLM) and resulting part properties is necessary. The SLM process consists of three major sub-processes: powder coating, exposure, and material consolidation. According to the interaction of sub-processes, resulting processing conditions during SLM determine the part properties by changing micro structural pore number and distribution. In addition to absolute temperatures, the time-dependency of the thermal fields also influences the porosity of molten parts. Present process strategies tend to decrease building time by acceleration of the subprocesses. Apart from prior investigated acceleration of the exposure, the powder coating step is focused. Within the paper, the authors analyze the basic interactions between different coating parameters and part properties. The authors estimate an interaction between coating speed and resulting part properties due to a force impact caused by the moved coating mechanism. Therefore, specimens produced with different coating speeds are analyzed with imaging technologies as well as mechanical tests. Based on the investigations, new processing strategies can be established considering the forces applied to the powder bed during the coating process, as well as the unique compaction behavior of current and future used powders.

scholarly journals An Overview of Additive Manufacturing Technologies—A Review to Technical Synthesis in Numerical Study of Selective Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3895 ◽  
Author(s):  
Abbas Razavykia ◽  
Eugenio Brusa ◽  
Cristiana Delprete ◽  
Reza Yavari
Keyword(s):  
Numerical Simulation ◽  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Powder Bed Fusion ◽  
Laser Melting ◽  
Powder Bed ◽  
Part Quality ◽  
Melt Pool ◽  
Wide Range ◽  
Am Processes

Additive Manufacturing (AM) processes enable their deployment in broad applications from aerospace to art, design, and architecture. Part quality and performance are the main concerns during AM processes execution that the achievement of adequate characteristics can be guaranteed, considering a wide range of influencing factors, such as process parameters, material, environment, measurement, and operators training. Investigating the effects of not only the influential AM processes variables but also their interactions and coupled impacts are essential to process optimization which requires huge efforts to be made. Therefore, numerical simulation can be an effective tool that facilities the evaluation of the AM processes principles. Selective Laser Melting (SLM) is a widespread Powder Bed Fusion (PBF) AM process that due to its superior advantages, such as capability to print complex and highly customized components, which leads to an increasing attention paid by industries and academia. Temperature distribution and melt pool dynamics have paramount importance to be well simulated and correlated by part quality in terms of surface finish, induced residual stress and microstructure evolution during SLM. Summarizing numerical simulations of SLM in this survey is pointed out as one important research perspective as well as exploring the contribution of adopted approaches and practices. This review survey has been organized to give an overview of AM processes such as extrusion, photopolymerization, material jetting, laminated object manufacturing, and powder bed fusion. And in particular is targeted to discuss the conducted numerical simulation of SLM to illustrate a uniform picture of existing nonproprietary approaches to predict the heat transfer, melt pool behavior, microstructure and residual stresses analysis.

Factors of strength increasing of metals produced by selective laser melting of powders

2019 ◽  
pp. 68-75 ◽  
Author(s):  
B. K. Barakhtin ◽  
A. S. Zhukov ◽  
V. V. Bobyr ◽  
I. V. Shakirov ◽  
P. A. Kuznetsov
Keyword(s):  
Chemical Composition ◽  
Selective Laser Melting ◽  
Mechanical Tests ◽  
Strength Characteristics ◽  
Strength Increase ◽  
Metal Powders ◽  
Laser Melting ◽  
Standard Samples ◽  
Ultrafine Grained ◽  
Identical Chemical Composition

Standard samples of metal powders of various chemical composition were made for mechanical tests by selective laser melting. The paper describes an increase in strength characteristics of all samples made by melting comparing with similar parameters of monolithic samples of identical chemical composition. It is established that ultrafine-grained structure and condensation of nanoparticles could be cosidered factors of strength increase.

Fabrication of Removable Partial Denture Framework by Selective Laser Melting

2011 ◽  
Vol 317-319 ◽  
pp. 174-178 ◽  
Author(s):  
Guang Xia Chen ◽  
Xiao Yan Zeng ◽  
Ze Min Wang ◽  
Kai Guan ◽  
Chang Wen Peng
Keyword(s):  
Selective Laser Melting ◽  
Powder Coating ◽  
Gas Purification ◽  
Laser Melting ◽  
Removable Partial Denture ◽  
Partial Denture ◽  
Optical Scanner ◽  
Single Piece ◽  
Purification System ◽  
Novel Method

The removable partial denture framework is very complex in shape with many curved surfaces, which is a very important assistant tool in prosthodontics. Generally, frameworks are fabricated by single piece basing on mould by traditional cast technology, which has many shortages of multiple steps, time cost and defects such as sand adheres, inner holes, cracks and segregation etc. As a novel method, selective laser melting (SLM) rapid prototyping technology has the advantages of short manufacturing cycle, high precision and flexibility, simple fabrication arts, which can be used to replace the conventional cast technology in the areas of prosthodontics. A SLM system was designed and developed by ourselves, which is consisted of an Yb-fiber laser, an optical scanner, a powder coating device, a gas purification system and a control system, the process parameters were investigated systematically and optimized, finally fabricated removable partial denture frameworks with stainless steel and titanium materials successfully by using the SLM system under optimized parameters. The tests showed that the frameworks have an average dimension precision of ±0.172mm. The wearing experiments on the plaster mouth molds demonstrated the removable partial denture frameworks fabricated by SLM can be fully applied to clinic after some post- processing procedures.

Selective Laser Melting of the Inconel 718 Nickel Superalloy

2014 ◽  
Vol 698 ◽  
pp. 333-338 ◽  
Author(s):  
Vadim Sh. Sufiiarov ◽  
Evgenii V. Borisov ◽  
Igor A. Polozov
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Inconel 718 ◽  
Melting Process ◽  
Nickel Superalloy ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Influence Of Process Parameters ◽  
Inconel 718 Superalloy

The results of the research on selective laser melting process of the Inconel 718 superalloy powder under conditions of additive manufacturing of parts for special purposes are presented. The influence of process parameters on the quality of manufactured parts is shown. Process parameters which allow manufacturing parts with the density close to 100%, are determined. Also, the results of mechanical tests and investigation of microstructure are presented.

Microstructure and Mechanical Properties of Inconel 718 Produced by SLM and Subsequent Heat Treatment

2015 ◽  
Vol 651-653 ◽  
pp. 665-670 ◽  
Author(s):  
Anatoly A. Popovich ◽  
Vadim Sh. Sufiiarov ◽  
Igor A. Polozov ◽  
Evgenii V. Borisov
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Elevated Temperatures ◽  
Ductile Failure ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Before And After

The article presents results of selective laser melting of Inconel 718 superalloy. It was studied phase microstructure of the material obtained by selective laser melting and also the material after heat treatment. The phase composition of the initial powder material, the specimens after selective laser melting before and after heat treatment was studied. The effect of heat treatment on microstructure and mechanical properties of the specimens was shown. It was studied the mechanical behavior of the manufactured specimens before and after heat treatment at room and elevated temperatures as well. The results of impact tests and fractography of the specimens are presented. Mechanical tests showed that the specimens after heat treatment have decent mechanical properties comparable to hot-rolled material. Fractography showed that the obtained material is characterized by ductile failure mode with local elements of brittle fracture.

scholarly journals Microstructure and Mechanical Properties of NiTi-Based Eutectic Shape Memory Alloy Produced via Selective Laser Melting In-Situ Alloying by Nb

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2696
Author(s):  
Igor Polozov ◽  
Anatoly Popovich
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Selective Laser Melting ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Heat Treated ◽  
Powder Particles ◽  
Martensitic Phase Transformations ◽  
Nb Addition

This paper presents the results of selective laser melting (SLM) process of a nitinol-based NiTiNb shape memory alloy. The eutectic alloy Ni45Ti45Nb10 with a shape memory effect was obtained by SLM in-situ alloying using a powder mixture of NiTi and Nb powder particles. Samples with a high relative density (>99%) were obtained using optimized process parameters. Microstructure, phase composition, tensile properties, as well as martensitic phase transformations temperatures of the produced alloy were investigated in as-fabricated and heat-treated conditions. The NiTiNb alloy fabricated using the SLM in-situ alloying featured the microstructure consisting of the NiTi matrix, fine NiTi+β-Nb eutectics, as well as residual unmelted Nb particles. The mechanical tests showed that the obtained alloy has a yield strength up to 436 MPa and the tensile strength up to 706 MPa. At the same time, in-situ alloying with Nb allowed increasing the hysteresis of martensitic transformation as compared to the alloy without Nb addition from 22 to 50 °C with an increase in Af temperature from −5 to 22 °C.

Impact Testing of H13 Tool Steel Processed with Use of Selective Laser Melting Technology

2018 ◽  
Vol 919 ◽  
pp. 43-51 ◽  
Author(s):  
Michal Ackermann ◽  
Jiří Šafka ◽  
Lukáš Voleský ◽  
Jiří Bobek ◽  
Jitendra Reddy Kondapally
Keyword(s):  
Selective Laser Melting ◽  
Tool Steel ◽  
Mechanical Tests ◽  
Impact Testing ◽  
Pressure Casting ◽  
Laser Melting ◽  
Impact Properties ◽  
H13 Tool Steel ◽  
Processed Material ◽  
Aisi H13

This paper deals with experimental determination of toughness, hardness and impact properties of AISI H13 (DIN 1.2344) tool steel which was manufactured using Selective Laser Melting (SLM) technology. The H13 is a chromium-based tool steel which is primarily used for hot working applications such as pressure casting moulds for automotive industry. Evaluation of toughness and impact properties are vital for reliable use of SLM-processed material, especially in the case of highly loaded structures. Mechanical tests were carried out on printed specimens, subjected to thermal treatment and proper data were evaluated. For better understanding of differences between conventionally produced and SLM-processed material, same mechanical tests were done even for hot-rolled H13 tool steel. SLM-printed material shows more brittle behaviour than conventionally made material. This is most probably caused by combination of H13 thermal properties and fast melting and solidification due to SLM processing.

Determination of criteria for assessing of synthesized material structure degradation during selective laser melting of nickel-based superalloys

2021 ◽  
pp. 134-144
Author(s):  
A.G. Evgenov ◽  
S.V. Shurtakov ◽  
P.V. Ryzhkov ◽  
D.V. Zaytsev
Keyword(s):  
Selective Laser Melting ◽  
Low Cycle Fatigue ◽  
Mechanical Tests ◽  
Material Structure ◽  
Laser Melting ◽  
Short Term ◽  
Nickel Based Superalloy ◽  
Structure Degradation ◽  
Reasonable Choice ◽  
Synthesized Materials

The analysis of foreign publications in terms of effect assessing of the recycled powder material reusing frequency and the construction platform loading density on the impurities level, technological characteristics of recycled powder in the process of selective laser melting (SLM) and synthesized materials mechanical properties is performed. The results of mechanical tests set: short-term tensile and long-term strength, low-cycle fatigue of synthesized samples of VZh159 nickel-based superalloy with comparison of the structure studies results by TEM and X-ray energy dispersion microanalysys methods are analyzed for reasonable choice of the assessing criterion for the material structure degradation in the SLM process with increase in the construction platform loading density and the recycled powders involvement. It is shown that the most effective structure degradation assessing criterion for the SLM nickel-based superalloy material is short-term tensile strength tests at the maximum operating temperature.

Selective Laser Melting of AISI316L: Process Optimization and Mechanical Property Evaluation

2016 ◽  
Author(s):  
Erica Liverani ◽  
Andrea Gamberoni ◽  
Eleonora Balducci ◽  
Alessandro Ascari ◽  
Lorella Ceschini ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Process Parameters ◽  
Statistical Design ◽  
Mechanical Tests ◽  
Laser Melting ◽  
Porosity Formation ◽  
Process Gas ◽  
Property Evaluation ◽  
Hatch Spacing ◽  
Sem Analyses

The influence of selective laser melting (SLM) process parameters such as laser power, build direction and scan hatch spacing on mechanical properties, microstructures and porosity formation in AISI 316L components is presented. Experimental activities are performed based on a statistical design-of-experiment approach based on a three-factor, two-level experimental plane. Mechanical tests, as well as optical and SEM analyses were carried out to correlate the resulting microstructures and defects to the process parameters. In order to better characterize the process, gas type, gas flux, coater speed and component positioning were also taken into account.

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