scholarly journals Process Optimization Variables for Direct Metal Laser Sintering

2015 ◽  
Vol 15 (4) ◽  
pp. 38-51 ◽  
Author(s):  
Ż. A. Mierzejewska
Keyword(s):  
Selective Laser Sintering ◽  
Minimum Energy ◽  
Systems Design ◽  
Laser Sintering ◽  
Physical Models ◽  
Cad Model ◽  
Direct Metal Laser Sintering ◽  
3D Cad ◽  
Short Period ◽  
Wide Range

AbstractManufacturing is crucial to creation of wealth and provision of quality of life. Manufacturing covers numerous aspects from systems design and organization, technology and logistics, operational planning and control. The study of manufacturing technology is usually classified into conventional and non-conventional processes. As it is well known, the term "rapid prototyping" refers to a number of different but related technologies that can be used for building very complex physical models and prototype parts directly from 3D CAD model. Among these technologies are selective laser sintering (SLS) and direct metal laser sintering (DMLS). RP technologies can use wide range of materials which gives possibility for their application in different fields. RP has primary been developed for manufacturing industry in order to speed up the development of new products (prototypes, concept models, form, fit, and function testing, tooling patterns, final products - direct parts). Sintering is a term in the field of powder metallurgy and describes a process which takes place under a certain pressure and temperature over a period of time. During sintering particles of a powder material are bound together in a mold to a solid part. In selective laser sintering the crucial elements pressure and time are obsolete and the powder particles are only heated for a short period of time. SLS uses the fact that every physical system tends to achieve a condition of minimum energy. In the case of powder the partially melted particles aim to minimize their in comparison to a solid block of material enormous surface area through fusing their outer skins. Like all generative manufacturing processes laser sintering gains the geometrical information out of a 3D CAD model. This model is subdivided into slices or layers of a certain layer thickness. Following this is a revolving process which consists of three basic process steps: recoating, exposure, and lowering of the build platform until the part is finished completely.

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.

Laser Sinterization Aspects of PA2200 Biocompatible Powder - Spinal Cage Application

2015 ◽  
Vol 638 ◽  
pp. 352-356
Author(s):  
Dan Ioan Stoia ◽  
Cosmina Vigaru ◽  
Lucian Rusu
Keyword(s):  
Geometric Model ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Cad Model ◽  
Scaling Factors ◽  
Building Plane ◽  
Digital Caliper ◽  
Nominal Dimension

The paper presents the dimensional aspects of a generic spinal cage build up from PA2200 powder. The cage was manufactured by means of selective laser sintering (SLS) technology, on Formiga P100 machine. The geometric model of spinal cage was designed in SolidWorks by taking into account the requirements that have to be fulfilled by such an implant. The dimensional aspects refer to geometric dimensions along X, Y and Z axes measured on sample parts, when these were placed on a 4x4 matrix on the building plane. The measurements were conducted using a digital caliper having a precision of 0.01, and were presented together with the nominal dimension of the CAD model. In conclusion, some qualitative aspects regarding the setting of the scaling factors were underlined.

scholarly journals Fabrication of Porous SiC by Direct Selective Laser Sintering Effect of Boron Carbide

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 737
Author(s):  
Rongzhen Liu ◽  
Gong Chen ◽  
Yudi Qiu ◽  
Peng Chen ◽  
Yusheng Shi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Selective Laser Sintering ◽  
Minimum Energy ◽  
Laser Sintering ◽  
Extreme Conditions ◽  
Sintering Process ◽  
Application Performance ◽  
Chemical Corrosion ◽  
Porous Sic ◽  
Sintered Silicon

Additive manufactured porous SiC is a promising material applied in extreme conditions characterised by high temperatures, chemical corrosion, and irradiation etc. However, residual Si’s existence deteriorates its performance and limits its application in harsh environments. In this study, B4C was introduced into the selective laser sintering process of SiC, and its effects on forming ability, pore parameters, microstructure, and phases were investigated. The results showed that when B4C was added, the processing window was enlarged. The minimum energy density was reduced from 457 J/cm2 to 214 J/cm2 when the content of B4C reached 15 wt%. Microstructure orientation was enhanced, and the residual silicon content was decreased from 38 at.% to about 8 at.%. Small pores were turned into large pores with the increase of B4C addition. The findings indicate that the addition of B4C increases the amount of liquid phase during the laser sintering process of silicon carbide, improving the SiC struts’ density and reducing the residual silicon by reacting with it. Therefore, the addition of B4C will help improve the application performance of selected laser-sintered silicon carbide under extreme conditions.

scholarly journals Additive Manufacturing: A next gen fabrication

2018 ◽  
Vol 8 (01) ◽  
Author(s):  
Prajakta Subhedar
Keyword(s):  
Rapid Prototyping ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Consumer Products ◽  
Cad Model ◽  
Final Model ◽  
Fused Deposition ◽  
Layer Manufacturing ◽  
Deposition Modeling

A class of technologies referring to Rapid Prototyping (RP) or Additive or Layer Manufacturing or 3D Printing allows designers to quickly create tangible prototype instead of using two dimensional pictures. This technology produces models and prototype parts from 3D CAD model data created from 3D object digitizing systems. Rapid Prototyping forms parts by joining together liquid, powder or sheet materials. Physical models are built using three basic stages: pre-processing, building, post-processing. Pre-processing consists of generation of CAD model, convert into STL format and slice the STL files into cross sectional layers. In building process, construction of model takes place one layer atop another. Post process consists of cleaning and finishing the final model. Common types of Rapid Prototyping technologies popular in industry are: Steriolithography, Fused Deposition Modeling, Selective Laser Sintering, Laminated Object Manufacturing,3 D Printing. The selection of the processes depends upon the material to be cured to build the final model. Rapid Prototyping technologies are used in various industries like Automobiles, Consumer products, Medical, Academics, Aerospace, Government and Military. This poster talks about few challenges to be considered in Rapid Prototyping like shrinkage and distortion of final model, mechanical performance of RP model and limitations to mass quantity. : Layer Manufacturing, CAD Model, STL format, Steriolithography, Fused Deposition Modeling, Selective Laser Sintering.

scholarly journals МЕТОД СОЗДАНИЯ МОДЕЛЕЙ САМОЛЕТОВ С ПОМОЩЬЮ СИСТЕМ CAD/CAM/CAE И АДДИТИВНЫХ ТЕХНОЛОГИЙ

2018 ◽  
pp. 24-34
Author(s):  
Ю. Б. Витязев ◽  
А. Г. Гребеников ◽  
А. М. Гуменный ◽  
А. М. Ивасенко ◽  
А. А. Соболев
Keyword(s):  
Additive Manufacturing ◽  
Fused Deposition Modeling ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Additive Technologies ◽  
Direct Metal Laser Sintering ◽  
Fused Deposition ◽  
Cad Cam ◽  
Deposition Modeling ◽  
Laser Stereolithography

The analysis of the most applicable in mechanical engineering additive technologies (fused deposition modeling, selective laser sintering, laser stereolithography, direct metal laser sintering) have been performed. Method of creating airplane models using CAD/CAM/CAE systems and additive manufacturing is presented. The results of the application of selective laser sintering and fused deposition modeling for the manufacture of training aircraft models are considered.

Selective Laser Sintering of Biomaterials and Composites State of the Art and Perspectives

2020 ◽  
Vol 1012 ◽  
pp. 278-283
Author(s):  
Henrique Schappo ◽  
Lya Piaia ◽  
Dachamir Hotza ◽  
Gean Vitor Salmoria
Keyword(s):  
Review Paper ◽  
Complex Geometry ◽  
State Of The Art ◽  
Complex Structure ◽  
Selective Laser Sintering ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Manufacturing Processes ◽  
Bone Scaffolds ◽  
Wide Range

Human bone has a complex geometry, varying its structure and composition. Additive manufacturing processes, such as selective laser sintering (SLS), can produce bone scaffolds with a wide range of biomaterials. Through SLS a complex structure with highly interconnected porous can be fabricated from a combination of materials. Composites made from biopolymers and bioceramics have shown promising results for bone regeneration, although some properties still must be enhanced. Finding suitable processing parameters is mandatory to achieve required final properties. This review paper is focused on polymer/ceramics using SLS machines in the last 10 years.

Study on the Dimensional Precision of the Polymer SLS Prototype

2005 ◽  
Vol 291-292 ◽  
pp. 597-602 ◽  
Author(s):  
H.J. Liu ◽  
Y.M. Li ◽  
Yuan Hao ◽  
N.Y. Huang ◽  
Yu Sheng Shi
Keyword(s):  
Influencing Factors ◽  
Manufacturing System ◽  
Selective Laser Sintering ◽  
Cad Model ◽  
Sintering Process ◽  
Dimensional Changes ◽  
Dimensional Precision ◽  
Wide Range ◽  
Dimension Precision ◽  
Sintering Shrinkage

Selective Laser Sintering (SLS) has many advantages such as fast building speed, wide range of materials, complicate shape of prototype and simple post-treatment. However, the shrinkage and mechanical stresses result in lost of the accuracy. This paper investigates the dimension precision of polymer SLS prototypes and proposes methods to control dimensions in suitable degree. The influencing factors of dimensional precision in the file preparation of CAD model, manufacturing system of SLS prototype and sintering process are analyzed. It indicates that the sintering shrinkage in sintering process is the main reason of dimensional changes. To improve the dimensional precision, the measures are proposed to diminish the shrinkage: improving material of prototype, optimizing the sintering process and compensating the lost of dimension. After analysis the experimental results, the rule of error changes is summarized by fitting equations and feedback to controlling software of SLS system to improve the dimensional precision effectively. The SLS prototype could be controlled in 100±0.20mm through compensation.

Study on Dimension Change Law from CAD Model to Prototype of Rapid Investment Casting Based on Selective Laser Sintering

2013 ◽  
Vol 774-776 ◽  
pp. 1046-1050
Author(s):  
Gang Lu ◽  
Shuai Xu ◽  
Qing Song Yan ◽  
Xu Xiong ◽  
Huan Yu
Keyword(s):  
Investment Casting ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Cad Model ◽  
Injection Process ◽  
Staircase Effect ◽  
Dimension Change ◽  
Length Width ◽  
Model Size ◽  
The Cost

Rapid Investment Casting can overcome the cost involved in designing and fabrication of metal tooling for wax injection process. The present investigation is aimed to determine the effects of CAD model placement degree and size on the dimension error of prototype base on Selective Laser Sintering. The experimental results show that the dimension change law of length, width and height is different from each other, it mainly due to the intersection angle between important edge and forming plane. When the angle is 0° and 90°, staircase effect is smaller and dimension accuracy is higher, when the angle is 45°, the staircase effect is biggest and dimension accuracy is lowest. The CAD model size has significantly influence on dimension accuracy because of secondary sintering, when the model size is 86mm, the secondary sintering reduces to minimum, the dimension error is 0, the secondary sintering is more obvious with the decrease of CAD model dimension.

scholarly journals Effects of Fabrication Parameters on the Properties of Parts Manufactured with Selective Laser Sintering: Application on Cement-Filled PA12

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Abdelrasoul M. Gadelmoula ◽  
Saleh A. Aldahash
Keyword(s):  
Laser Power ◽  
Laser Energy ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Morphological Properties ◽  
Vector Length ◽  
Incident Laser Power ◽  
White Cement ◽  
Wide Range ◽  
Fabrication Parameters

Selective laser sintering (SLS) becomes a promising technology for manufacturing complicated objects with small to moderate numbers from a wide range of polymeric and metallic powders. However, the fabrication parameters in the SLS process need to be tailored for each end-use fabricated product. Hence, it becomes extremely important to investigate the effects of fabrication parameters on the mechanical and morphological properties of SLS parts. For this purpose, the present experimental work is devoted to evaluating the effects of some important fabrication parameters, that have not received proper attention in the published literature, on the properties of cement-filled polyamide 12 (PA12) parts manufactured with the SLS technique. The effect of scanning vector length on the tensile, compressive, and flexural strength of manufactured PA12/white cement parts is investigated. Also, the end-of-vector (EOV) effect on the edge geometry of manufactured parts is studied. Moreover, the effect of incident laser power (LP) on the surface quality of fabricated SLS PA12/white cement parts is qualitatively evaluated. The results from this work revealed that the scanning vector length significantly affects the mechanical properties of SLS parts provided that the load is applied along the scanning vector direction. Also, it is noticed that excessive exposure to laser energy at layer edges can deteriorate the part’s edge and in some cases can cause localized heating and burning of the part’s edge and, eventually, can result in surface microcracks. Finally, the experiments confirmed that increasing the laser power can enhance the surface roughness of manufactured parts; however, excessive increase in laser power causes localized burning and initiation of surface microcracks.

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