Rapid Manufacturing with Direct Metal Laser Sintering

2002 ◽  
Vol 758 ◽  
Author(s):  
J-E. Lind ◽  
J. Hanninen ◽  
J. Kotila ◽  
O. Nyrhila ◽  
T. Syvanen
Keyword(s):  
Surface Roughness ◽  
Layer Thickness ◽  
Process Development ◽  
Die Casting ◽  
Laser Sintering ◽  
Thin Layers ◽  
Rapid Manufacturing ◽  
Manufacturing Processes ◽  
Direct Metal Laser Sintering ◽  
Process Work

ABSTRACTThe term Rapid Manufacturing is today very often used as a substitute for Rapid Prototyping, because the manufacturing processes and materials have developed so much that the parts produced with the machines can even be used as functional production parts. For Direct Metal Laser Sintering (DMLS) this was enabled by the introduction of the powders for 20 micron layer thickness; steel-based powder in 2001 and bronze-based powder in 2002. Successful rapid manufacturing with DMLS does not only mean the reduction of layer thickness, but it is a sum of many factors that had to be optimized in order to make the process work with the 20 micron layer thickness: the metal powder behavior in very thin layers is not the same as with thicker layers, the demands for the support structures are higher and the possibility of using multiples of the layer thickness gives additional freedom. By optimizing the process parameters the UTS values for the steel-based powder increased up to 600 MPa and for the bronze-based powder up to 400 MPa. At the same time the surface roughness (Ra) values after shot peening were 3 microns and 2 microns, respectively. Although using thinner layers also increases the building time the advantage is gained in drastically reduced finishing times due to increased surface quality and detail resolution. Typical geometries produced by DMLS are difficult-to-manufacture components and components typically produced by P/M or even by die-casting. The paper covers the development aspects in both material and process development and also presents some realized case studies.

Surface Roughness Improvement Using Laser-Polishing Techniques

2006 ◽  
Vol 526 ◽  
pp. 217-222 ◽  
Author(s):  
Aitzol Lamikiz ◽  
Jose Antonio Sánchez ◽  
Luis Norberto López de Lacalle ◽  
D. del Pozo ◽  
J.M. Etayo
Keyword(s):  
Surface Roughness ◽  
Selective Laser Sintering ◽  
Roughness Parameter ◽  
Laser Sintering ◽  
Rapid Manufacturing ◽  
Manufacturing Processes ◽  
Roughness Parameters ◽  
Metallic Surfaces ◽  
Laser Polishing ◽  
Geometric Deviations

A laser polishing method applied on metallic surfaces is presented in this work. One of the most important applications of this technique is the small-medium injection mould polishing manufactured by rapid manufacturing processes (RM) such as selective laser sintering. The polishing method has been applied to different surfaces including a laser-sintered part. Topography and roughness parameters measurements show that laser polishing can achieve surface improvements up to three times in mean roughness parameter with no macro-geometric deviations.

Mass Finishing of Parts Produced by Direct Metal Laser Sintering

Volume 3 ◽  
2004 ◽  
Author(s):  
A. Boschetto ◽  
F. Veniali ◽  
F. Miani
Keyword(s):  
Surface Roughness ◽  
Industrial Process ◽  
Mechanical Action ◽  
Laser Sintering ◽  
Main Process ◽  
Direct Metal Laser Sintering ◽  
Complicated Shape ◽  
Mass Finishing ◽  
Barrel Finishing ◽  
Established Technique

This paper presents some practical considerations on finishing of parts made by direct metal laser sintering (DMLS). The main process capabilities limitations of this promising rapid tooling technique are in fact in the surface roughness of the produced parts. This fact hinders the introduction of DMLS as a widely employed industrial process, especially for what concerns the production of moulds and inserts and allows their use only as preseries tools in injection moulding of plastics, since the requirements for preseries tools are worse than those needed during the process. Barrel finishing, in turn, is a well established technique to improve the roughness of parts of complicated shape by means of a soft mechanical action over the surface. The results herewith presented show that it is possible to achieve roughness of the order of 1 μm Ra even when starting from initial roughness of the order of 15 μm Ra, i.e. those typically attained by DMLS.

scholarly journals An Analysis of the Surface Geometric Structure and Geometric Accuracy of Cylindrical Gear Teeth Manufactured with the Direct Metal Laser Sintering (DMLS) Method

2019 ◽  
Author(s):  
Jadwiga Małgorzata Pisula ◽  
Grzegorz Budzik ◽  
Łukasz Przeszłowski
Keyword(s):  
Surface Roughness ◽  
Geometric Structure ◽  
Gear Tooth ◽  
Spur Gear ◽  
Laser Sintering ◽  
Tooth Surface ◽  
Direct Metal Laser Sintering ◽  
Cylindrical Gear ◽  
Sand Blasting ◽  
Gear Teeth

This paper presents findings concerning the accuracy of the geometry of cylindrical spur gear teeth manufactured with the direct metal laser sintering (DMLS) method. In addition, the results of the evaluation of the tooth surface geometric structure are presented in the form of selected two-dimensional and three-dimensional surface roughness parameters. An analysis of the accuracy of the fabricated gear teeth was performed after gear sand-blasting and gear tooth milling processes. Surface roughness was measured before and after sand-blasting and gear tooth milling. The test gear wheel was manufactured from GP1 high-chromium stainless steel on an EOS M270 machine.

Surface roughness and densification correlation for direct metal laser sintering

2020 ◽  
Vol 107 (5-6) ◽  
pp. 2833-2842 ◽  
Author(s):  
Faridreza Attarzadeh ◽  
Behzad Fotovvati ◽  
Michael Fitzmire ◽  
Ebrahim Asadi
Keyword(s):  
Surface Roughness ◽  
Laser Sintering ◽  
Direct Metal Laser Sintering

Influence of Process Parameters on Surface Finish in Customized Bone Implant Using Selective Laser Sintering

2013 ◽  
Vol 845 ◽  
pp. 862-867 ◽  
Author(s):  
K. Swarna Lakshmi ◽  
G. Arumaikkannu
Keyword(s):  
Surface Roughness ◽  
Layer Thickness ◽  
Surface Finish ◽  
Signal To Noise Ratio ◽  
Statistical Significance ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Influence Of Process Parameters ◽  
Bone Implant ◽  
Computer Tomography Scan

Selective Laser Sintering(SLS) is a powder-based Additive Manufacturing process in which parts are built by sintering of selected areas of layers of Polyamide (PA12) powder using CO2 laser. The purpose of this work is to study experimentally the effect of orientation of the component, fill scan spacing and layer thickness on the surface roughness (Ra) of the customized bone implant fabricated through SLS technique. For this study computer tomography scan data was taken and converted to standard triangulation file (.stl) format using mimics software. Taguchis Design of Experiment approach was used for this study. An L27 Orthogonal Array (OA) of Taguchi design was used. Analysis of Variance (ANOVA) was then performed on S/N (Signal-to-Noise ratio) to determine the statistical significance and contribution of each factor on the surface roughness. The results indicated that orientation and layer thickness are significant parameters to cause appreciable improvement in surface finish.

Experimental Study of Direct Metal Laser Sintering: High Cycle Fatigue Life and Process Parameters

2020 ◽  
Author(s):  
Riley Seyffert ◽  
Sudhir Kaul
Keyword(s):  
Fatigue Life ◽  
Layer Thickness ◽  
Process Parameters ◽  
High Cycle Fatigue ◽  
Laser Sintering ◽  
Bending Test ◽  
Cycle Fatigue ◽  
Direct Metal Laser Sintering ◽  
Build Time ◽  
Scan Speed

Abstract Direct Metal Laser Sintering (DMLS) is a relatively new manufacturing process in additive manufacturing (AM) that fuses powdered metal by using a high-powered laser. Although this process allows manufacturing prototypes without requiring specific tooling, it is challenging to use this process for manufacturing high volume production parts since complex shapes can take a significant amount of build time. Furthermore, manufactured parts also need some amount of post-processing to remove the support material that may be required due to the layer-by-layer build process. This study investigates three process parameters that could be optimized to substantially reduce production time. These three parameters are as follows: build layer thickness, laser scan speed, and laser hatch distance. In order to evaluate the influence of these parameters, manufactured parts made of AISI 316L Stainless Steel are tested for fatigue life and static strength. A three-point bending test is used as per ASTM E466. While none of the three parameters is seen to significantly influence ultimate tensile strength, results indicate that build layer thickness is a significant process parameter that directly affects fatigue life. Furthermore, the interaction between build layer thickness and laser scan speed is found to be statistically significant for high cycle fatigue. However, laser scan speed and laser hatch distance are seen to be statistically insignificant for fatigue life. The initial results of this study indicate that process parameters of DMLS need to be selected judiciously in order to minimize build time while maintaining structural integrity.

scholarly journals Effect of plasma nitriding of austenitic stainless steel produced by direct metal laser sintering

2021 ◽  
Vol 27 (4) ◽  
pp. 190-194
Author(s):  
Dorina Kovács ◽  
Dávid Miklós Kemény
Keyword(s):  
Surface Roughness ◽  
Raw Materials ◽  
Plasma Nitriding ◽  
Austenitic Stainless Steels ◽  
Laser Sintering ◽  
Direct Metal Laser Sintering ◽  
Direct Current Plasma ◽  
Wide Range ◽  
Optical Electron

A special additive manufacturing (AM), called as Direct Metal Laser Sintering (DMLS), is a technology that produces 3D workpieces using a wide range of different metals as raw materials. The aim of current research is to investigate the plasma nitriding effect on the DMLS produced samples. The direct current plasma nitriding treatment was achieved at 440 °C for 4 hours with 75%N2 – 25%H2 gas mixture. Before the treatment, the 316L austenitic stainless steels samples were ground with different methods to modify the surface roughness. Scanning electron microscope (SEM), X-ray diffractometer, glow discharge optical electron spectroscopy, Vickers microhardness tester and potentiodynamic corrosion test were used for the characterization of surface properties. The results demonstrated that the surface roughness did not affect the outcome of the plasma nitriding, but the corrosion resistance increases with the decrease of the surface roughness compared to the untreated 3D sample.

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