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.

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.

A Study on Topology of Lateral Surface of Components Manufactured by Selective Laser Sintering

2012 ◽  
Vol 584 ◽  
pp. 357-360
Author(s):  
C.D. Naiju ◽  
M. Adithan ◽  
P. Radhakrishnan ◽  
K. Annamalai
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Lateral Surface ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Surface Topology ◽  
Main Process ◽  
Slice Thickness ◽  
Developed Surface ◽  
Main Process Parameter

This work presents the results of a study carried out to determine the topology of lateral surface and its effect on the process parameters of components manufactured by selective laser sintering (SLS). Using Taguchi’s experimental technique, an orthogonal array of L4 had been developed. Surface roughness was measured along built direction and analysis of variance (ANOVA) technique was used to investigate the effect of process parameters and to identify main process parameter that influences surface roughness on SLS components. It has been found that slice thickness and scan spacing have more significant influence than the laser power. Microstructure of the sintered specimen along the build direction was studied using Scanning Electron Microscope (SEM). It was observed that variations in slice thickness affect surface topology of SLS components.

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

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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