Investigations for Safe Grinding of Ti-6Al-4V Parts Produced by Direct Metal Laser Sintering (DMLS) Technology

2014 ◽  
Author(s):  
Radu Pavel ◽  
Anil K. Srivastava
Keyword(s):  
Titanium Alloy ◽  
Additive Manufacturing ◽  
Residual Stresses ◽  
Diffraction Method ◽  
Laser Sintering ◽  
Grinding Wheel ◽  
Material Structure ◽  
Direct Metal Laser Sintering ◽  
Machining Processes ◽  
Grinding Conditions

Direct Metal Laser Sintering (DMLS) is an additive manufacturing technology that can construct medium to small size parts very efficiently in comparison to traditional machining processes. The ability of this technology to grow complex parts made of high strength titanium- and nickel-based alloys led to increasing interest from aerospace, defense, and medical industries. Although the technology allows growing parts close to their final shape, the active surfaces still need a finishing operation such as grinding to meet the tight tolerances and surface finish requirements. Due to the novelty of the DMLS technology, and the relatively recent developments of titanium alloy powders, there is a need for testing and validating the capabilities of the components manufactured through a combination of DMLS and grinding processes. This paper presents the findings of an experimental study focused on the effect of various grinding conditions on the surface integrity of titanium alloy (Ti-6Al-4V) specimens produced using DMLS technology. The goal is to identify dressing and grinding conditions that would result in ground surfaces free of defects such as micro-cracks, discoloration of surfaces and/or burn marks due to high heat generated during grinding. The residual stresses were used to quantify the effect of the grinding conditions on the ground surfaces. These investigations were conducted on an instrumented CNC surface grinding machine, using a silicon-carbide grinding wheel and a water-based fluid. The X-ray diffraction method was used to measure the residual stresses. Two batches of specimens were manufactured for these tests. The growing strategy of the specimens and the presence of apparent defects in material structure are considered some of the main causes for the differences observed in the outcomes of the grinding trials. The results of these investigations support the need for continuing research in the additive manufacturing field to develop methods and technologies that will ensure a high level of consistency of the grown parts.

scholarly journals Mechanical properties comparison of Ti6Al4V produced by different technologies under static load conditions

2019 ◽  
Vol 290 ◽  
pp. 08010
Author(s):  
Karolina Karolewska ◽  
Bogdan Ligaj
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Ti6al4v Alloy ◽  
Direct Metal Laser Sintering ◽  
Static Tests ◽  
Rolling Method ◽  
Manufacturing Techniques ◽  
Materials Used

The most commonly used technology among the additive manufacturing is Direct Metal Laser Sintering (DMLS). This process is based on selective laser sintering (SLS). The method gained its popularity due to the possibility of producing metal parts of any geometry, which would be difficult or impossible to obtain by the use of conventional manufacturing techniques. Materials used in the elements manufacturing process are: titanium alloys (e.g. Ti6Al4V), aluminium alloy AlSi10Mg, etc. Elements printed from Ti6Al4V titanium alloy find their application in many industries. Details produced by additive technology are often used in medicine as skeletal, and dental implants. Another example of the DMLS elements use is the aerospace industry. In this area, the additive manufacturing technology produces, i.a. parts of turbines. In addition to the aerospace and medical industries, DMLS technology is also used in motorsport for exhaust pipes or the gearbox parts. The research objects are samples for static tests. These samples were made of Ti6Al4V alloy by the DMLS method and the rolling method from a drawn rod. The aim of the paper is the mechanical properties comparative analysis of the Ti6Al4V alloy produced by the DMLS method under static loading conditions and microstructure analysis of this material.

Material Analysis of Titanium Alloy Produced by Direct Metal Laser Sintering

2013 ◽  
Vol 7 (2) ◽  
pp. 43-50 ◽  
Author(s):  
J. Sedlák ◽  
M. Ptáčková ◽  
J. Nejedlý ◽  
M. Madaj ◽  
J. Dvořáček ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Laser Sintering ◽  
Direct Metal Laser Sintering ◽  
Material Analysis

scholarly journals Effect of Cutting Conditions on the Residual Stresses Induced by Milling of AISI 1045 Steel

2019 ◽  
Vol 8 (2) ◽  
pp. 1462-1465 ◽  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Diffraction Method ◽  
Cutting Conditions ◽  
Depth Of Cut ◽  
Machining Processes ◽  
Machined Surface ◽  
Aisi 1045 Steel ◽  
Aisi 1045 ◽  
1045 Steel

The nature of residual stresses caused by machining processes has been relevant to the study of component performance for decades. The concept that cutting parameters affect the magnitude and nature of residual stress is well known. In order to reduce the residual stresses on a machined surface, it is important to identify the extent of the effect of cutting conditions. This paper presents the effect of depth of cut and tool speed on milling induced residual stresses. Speed and depth of cut were varied when milling several AISI 1045 Steel specimens. Stresses were measured with the X-ray diffraction method and corroborated with mathematical modelling on an FEA software. A relationship between tool speed and residual stress, and depth of cut and residual stress was thus obtained.

scholarly journals Digital Modeling Accuracy of Direct Metal Laser Sintering Process

2020 ◽  
Vol 22 (2) ◽  
pp. 123
Author(s):  
T. Dmitriyev ◽  
S. Manakov
Keyword(s):  
Additive Manufacturing ◽  
Main Idea ◽  
Strength Properties ◽  
Laser Sintering ◽  
Direct Metal Laser Sintering ◽  
Real Model ◽  
Digital Modeling ◽  
Critical Issues ◽  
Metal 3D Printing ◽  
The Cost

Products obtained by metal additive manufacturing have exceptional strength properties that can be compared with forged parts, and in some cases, even surpass them. Also, the cost and time of parts manufacture are reduced by two or even three times. Because of this, today’s leading corporations in the field of aerospace industry introducing this technology to its production. To avoid loss of funds and time, the processes of additive manufacturing should be predictable. Simufact Additive is specialized software for additive manufacturing process simulation is dedicated to solving critical issues with metal 3D printing, including significantly reducing distortion; minimize residual stress to avoid failures; optimize the build-up orientation and the support structures. It also enables us to compare simulated parts with the printed sample or measure it as a reference. In other words, the simulated deformations can be estimated concerning the reference geometry. The current work aims to study the deformation of the sample during the Direct Metal Laser Sintering (DMLS) process made from Maraging Steel MS1. Simufact Additive software was used to simulate the printing process. The main idea is to compare the results of the simulation and the real model. EOS M290 metal 3D printer was used to make a test specimen.

Effect of Build Direction in Direct Metal Laser Sintering (DMLS) of Inconel 718 on Microstructure and Mechanical Behavior

2019 ◽  
Author(s):  
Sachin Alya ◽  
Chaitanya Vundru ◽  
Ramesh Singh ◽  
Khushahal Thool ◽  
Indradev Samajdar ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Behavior ◽  
Inconel 718 ◽  
Laser Sintering ◽  
Thermal Gradients ◽  
Layer By Layer ◽  
Direct Metal Laser Sintering ◽  
Powder Bed ◽  
Grain Orientations ◽  
End Use

Abstract Additive manufacturing (AM) technology is gaining enormous popularity in the manufacturing industries. The continuous improvements made in the AM processes features development of 3D metallic prototypes as well as fully functional end-use components. Direct Metal Laser Sintering (DMLS) is a pre-placed powder bed based technique, in which a thin layer of powder is place over the build tray and the areas need to be sintered are exposed to the laser. In the current work the microstructural and mechanical behavior of Inconel 718 parts produced by DMLS are investigated. As the DMLS produces parts in a layer by layer fashion, the orientation of parts with respect to the build direction is an important criterion. Microstructure and mechanical properties of the produce differs depending upon the orientation. This paper emphasize on the variation of grain sizes and grain orientations developed in the components built with different orientations. Another common issue with the additive manufacturing is the development of the residual stresses in the components arising due to the differential thermal gradients experienced during processing. The variation of the residual stress generated in the produced parts has also been characterized and modeled.

Game Theoretic Modelling Approach for Optimizing Direct Metal Laser Sintering Process Parameters Using Artificial Neural Network

2020 ◽  
Author(s):  
Suchana Jahan ◽  
Hazim El-Mounayri
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Additive Manufacturing ◽  
Process Parameters ◽  
Laser Sintering ◽  
Optimization Techniques ◽  
Direct Metal Laser Sintering ◽  
Game Theoretic ◽  
Artificial Neural ◽  
Modelling Approach

Abstract Additive Manufacturing, also known as Rapid Prototyping and 3D Printing is a three-dimensional fabrication process, executed by adding materials in layers. Among many different classes of AM processes, Direct Metal Laser Sintering is a widely used metal part manufacturing method. The design, planning and implementation of overall DMLS process and its process parameters are yet to be optimized. To be able to render minimum defects as well as higher quantity of production, it is essential to apply ever developing computer technologies, data storage capabilities and optimization techniques. Typically, the defects on any 3D printed part can alter mechanical properties and shorten its durability. To minimize the defects and produce good quality parts at a mass level, has been a challenge in additive manufacturing industry. In this paper, a framework is presented to utilize game theoretic modelling approach to optimize DMLS process parameters. Online monitoring of DMLS process can identify defects of printed layers and correlate them with temperature signatures. An Artificial Neural Network is trained to predict printing defects and process parameters. predicted model can be further used in a game theoretic playoff matrix to identify the most optimal combination or configuration of DMLS process parameters to minimize defects and maximize the production quantity. The proposed method can also be applied in different domains of additive and advanced manufacturing.

X-Ray Residual Stress Measurement of Ground Tungsten Carbides with Various Cobalt Contents

1995 ◽  
Vol 39 ◽  
pp. 311-318
Author(s):  
Masaharu Miyano ◽  
Yukio Hirose
Keyword(s):  
Residual Stresses ◽  
Stress Measurement ◽  
Diffraction Method ◽  
Diamond Wheel ◽  
Tungsten Carbides ◽  
X Ray ◽  
Three Point Bending ◽  
Grinding Conditions ◽  
Co Addition ◽  
Straight Lines

The X-ray diffraction method was applied to the measurement of residual stresses on the ground or polished surfaces of WC-Co alloys with various Co contents. The X-ray diffractions of WC 211 by Cu K α radiation were used for the stress measurement. The residual stresses on the ground or polished surfaces were all compression. For the same Co content, the compressive value increased with increasing surface roughness. The maximum residua) stress, which was -2.13 GPa, was observed in WC-5.5wt%Co ground with a #140 diamond wheel.The bending strengths of each alloys were obtained by three point bending tests. The bending strengths were influenced by grinding conditions and Co contents. The maximum value of 3.6 GPa was obtained in WC-16.0wt%Co ground with a #140 diamond wheel.For the same Co addition, the bending strengths were closely related to the residual stresses, These relations were approximated by straight lines.

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