African Journal of Pure and Applied Science Education Volume 18, Number 1, pp 190 – 204, July 2020 www.ajopase.com; [email protected]ISSN 11187670 Umar, I, Ohwofasa, O & Janga, A. A AJOPASE, Vol. 18, No. 1, July 2020 pg. 190 INVESTIGATION INTO THE EFFECT OF BUILD PARAMETERS AND BUILD ANGLE ON THE DOWN SKIN SURFACES FOR STAINLESS STEEL LASER MELTED PARTS 1 Umar, I, 2 Ohwofasa, O, 3 Janga, A. A 1 Mechananical Engineering Department, Niger State Polytechnic, Zungeru, Niger State 2 Electrical Electronics Department, Federal College of Education Technical Akoka lagos 3 Mechananical Engineering Department, Federal Polytechnic, Damaturu, Yobe State [email protected][email protected][email protected]Abstract In the additive manufacturing [AM] technologies, several powder fusion technologies for obtaining metal parts can be adopted. The selective laser sintering technology was used in this experiment to investigate the effect of build parameters and build angle on the down skin surface for stainless steel laser melted parts. Some input parameters, such as laser power, scan speed, and hatching distance were selected for the investigation. The result shows that the surface roughness and surface parameters Ra average value at 45 o comparing it with all the other values, at the standard parameters settings, the minimum angle values for overhanging surfaces that can be considered acceptable for SLM process without the use of supports were ranging between 39⁰-45⁰.However, for overhanging surfaces with an angle below 36⁰ will require support structures are needed. The orientation of the part must be considered in the design stage in order to reduce the number of supports and avoid damaging the quality of the surface after their removal. Keywords: Selective Laser Sintering [SLM], Stainless Steel, Surface Roughness [Ra], Additive Manufacturing [AM] Introduction In the Additive Manufacturing (AM) industry several technologies have been developed, powder bed fusion being the leading technology for obtaining metal parts. Some of powder bed fusion processes are alternately known as selective laser sintering, selective laser melting, direct metal laser sintering, direct metal laser melting, and electron beam melting. All powder bed fusion processes have a similar basic operating principle. The main differences between processes are in the way layers are deposited to create parts and in the materials that are used (King et al., 2015). The design stage of the process starts by creating 3D CAD model of the desired object. Using a pre-defined slicing program, the 3D CAD file is converted into a series of thin parallel layers that fully describe the geometry of the desired object creating a 2D image of each layer (Direct Laser Metal Sintering, 2015). The data obtained is transferred to a computer controlled laser device. Depending on the equipment and the method used, thin layers of powder are spread with a recoating system onto a platform and a laser or electron beam is used to
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African Journal of Pure and Applied Science Education Volume 18, Number 1, pp 190 – 204, July 2020 www.ajopase.com; [email protected] ISSN 11187670
Umar, I, Ohwofasa, O & Janga, A. A AJOPASE, Vol. 18, No. 1, July 2020 pg. 190
INVESTIGATION INTO THE EFFECT OF BUILD PARAMETERS AND BUILD ANGLE ON THE DOWN SKIN SURFACES FOR STAINLESS STEEL LASER MELTED PARTS
1Umar, I, 2Ohwofasa, O, 3Janga, A. A 1Mechananical Engineering Department, Niger State Polytechnic, Zungeru, Niger State 2Electrical Electronics Department, Federal College of Education Technical Akoka lagos
Abstract In the additive manufacturing [AM] technologies, several powder fusion technologies for obtaining metal parts can be adopted. The selective laser sintering technology was used in this experiment to investigate the effect of build parameters and build angle on the down skin surface for stainless steel laser melted parts. Some input parameters, such as laser power, scan speed, and hatching distance were selected for the investigation. The result shows that the surface roughness and surface parameters Ra average value at 45o comparing it with all the other values, at the standard parameters settings, the minimum angle values for overhanging surfaces that can be considered acceptable for SLM process without the use of supports were ranging between 39⁰-45⁰.However, for overhanging surfaces with an angle below 36⁰ will require support structures are needed. The orientation of the part must be considered in the design stage in order to reduce the number of supports and avoid damaging the quality of the surface after their removal. Keywords: Selective Laser Sintering [SLM], Stainless Steel, Surface Roughness [Ra], Additive Manufacturing [AM]
Introduction In the Additive Manufacturing (AM) industry several technologies have been developed, powder bed
fusion being the leading technology for obtaining metal parts. Some of powder bed fusion processes are
alternately known as selective laser sintering, selective laser melting, direct metal laser sintering, direct
metal laser melting, and electron beam melting. All powder bed fusion processes have a similar basic
operating principle. The main differences between processes are in the way layers are deposited to
create parts and in the materials that are used (King et al., 2015). The design stage of the process starts
by creating 3D CAD model of the desired object. Using a pre-defined slicing program, the 3D CAD file is
converted into a series of thin parallel layers that fully describe the geometry of the desired object
creating a 2D image of each layer (Direct Laser Metal Sintering, 2015). The data obtained is transferred
to a computer controlled laser device. Depending on the equipment and the method used, thin layers
of powder are spread with a recoating system onto a platform and a laser or electron beam is used to
African Journal of Pure and Applied Science Education Volume 18, Number 1, pp 190 – 204, July 2020 www.ajopase.com; [email protected] ISSN 11187670
Umar, I, Ohwofasa, O & Janga, A. A AJOPASE, Vol. 18, No. 1, July 2020 pg. 203
Conclusion
An investigation into the effect of build angle and downskin condition obtained in SLM using Stainless
Steel has been presented to further the understanding of the relationship between surface roughness
and process parameters. It was found that for Stainless Steel, considering ideal the Ra average value
obtained at 45⁰, and comparing it with all the other values, at the standard parameters settings, the
minimum angle values for overhanging surfaces that can be considered acceptable for SLM process
without the use of supports are ranging between 39⁰- 45⁰. When the process parameters ware
modified, the minimum angle values for overhanging surfaces are ranging between 36⁰-45⁰.To
conclude, for overhanging surfaces with an angle below 36⁰ support structures are needed. The
orientation of the part must be considered in the design stage in order to reduce the number of supports
and avoid damaging the quality of the surface after their removal.
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African Journal of Pure and Applied Science Education Volume 18, Number 1, pp 190 – 204, July 2020 www.ajopase.com; [email protected] ISSN 11187670
Umar, I, Ohwofasa, O & Janga, A. A AJOPASE, Vol. 18, No. 1, July 2020 pg. 204
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