PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling

Despite advantages of selective laser sintering (SLS) to print complex and highvolume products, major concern in SLS process are exposures during handling especially during pre-processing. This study aims to formulate percentage of refresh rate with powder handling settings with the introduction...

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Main Author:	Muhamad Damanhuri, Amir Abdullah
Format:	Thesis
Language:	English English English
Published:	2021
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://eprints.uthm.edu.my/8397/1/24p%20AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI.pdf http://eprints.uthm.edu.my/8397/2/AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/8397/3/AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI%20WATERMARK.pdf
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spelling	my-uthm-ep.83972023-02-26T02:48:47Z PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling 2021-11 Muhamad Damanhuri, Amir Abdullah TJ Mechanical engineering and machinery Despite advantages of selective laser sintering (SLS) to print complex and highvolume products, major concern in SLS process are exposures during handling especially during pre-processing. This study aims to formulate percentage of refresh rate with powder handling settings with the introduction of enclosure during preprocessing stages to reduces dust exposures using response surface methodology (RSM) of central composites design (CCD) techniques. This research divides into three phases, as the first phase involves a pilot study to select pre-processing as the main contribution of emission. Analysis of variance and 95% confidence interval were used to identify factors and responses that significantly contributed to the IAQ in SLS workplaces involving 56 set of screening experiments using factorial design. Next, second phase involves series of experiments to formulate refresh rate, collecting powder from mixing machines and transferring activities due to enclosures settings using RSM techniques. Finally, the third phase involves assessing gravimetric based on personal sampling (based on NIOSH 0500 and 0600) for using enhanced model suggested by the RSM. Through screening analysis, it was obtained that refresh rate give significant percentage of contribution (72.73%) to the emission followed by collecting powder from mixing machine and transferring activity. From CCD analysis with 0.816 desirability suggested 100% refresh rate, 32.8% enclosure for collecting powder from mixing machine, and full enclosure for transferring process to reduce PM2.5, PM10, UFP and TSP. The confirmation experiment was also conducted to verify the prediction result using percentage of absolute error (%) with 4.33,3.57, 4.56 and 2.38 for PM2.5, PM10, UFP and TSP. Based on the enhanced model from RSM, performance experiments show acceptable percentage of reduction for 40.6 and 28.8 % of reduction for NIOSH 0500, and 22.7 and 27.3% for NIOSH 0600, respectively. The mathematical model from RSM shows promising strategy in term of control measures in protecting operators in SLS manufacturing industry from occupational exposures. 2021-11 Thesis http://eprints.uthm.edu.my/8397/ http://eprints.uthm.edu.my/8397/1/24p%20AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI.pdf text en public http://eprints.uthm.edu.my/8397/2/AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI%20COPYRIGHT%20DECLARATION.pdf text en staffonly http://eprints.uthm.edu.my/8397/3/AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI%20WATERMARK.pdf text en validuser phd doctoral Universiti Tun Hussein Onn Malaysia Fakulti Kejuruteraan Mekanikal dan Pembuatan
institution	Universiti Tun Hussein Onn Malaysia
collection	UTHM Institutional Repository
language	English English English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Muhamad Damanhuri, Amir Abdullah PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
description	Despite advantages of selective laser sintering (SLS) to print complex and highvolume products, major concern in SLS process are exposures during handling especially during pre-processing. This study aims to formulate percentage of refresh rate with powder handling settings with the introduction of enclosure during preprocessing stages to reduces dust exposures using response surface methodology (RSM) of central composites design (CCD) techniques. This research divides into three phases, as the first phase involves a pilot study to select pre-processing as the main contribution of emission. Analysis of variance and 95% confidence interval were used to identify factors and responses that significantly contributed to the IAQ in SLS workplaces involving 56 set of screening experiments using factorial design. Next, second phase involves series of experiments to formulate refresh rate, collecting powder from mixing machines and transferring activities due to enclosures settings using RSM techniques. Finally, the third phase involves assessing gravimetric based on personal sampling (based on NIOSH 0500 and 0600) for using enhanced model suggested by the RSM. Through screening analysis, it was obtained that refresh rate give significant percentage of contribution (72.73%) to the emission followed by collecting powder from mixing machine and transferring activity. From CCD analysis with 0.816 desirability suggested 100% refresh rate, 32.8% enclosure for collecting powder from mixing machine, and full enclosure for transferring process to reduce PM2.5, PM10, UFP and TSP. The confirmation experiment was also conducted to verify the prediction result using percentage of absolute error (%) with 4.33,3.57, 4.56 and 2.38 for PM2.5, PM10, UFP and TSP. Based on the enhanced model from RSM, performance experiments show acceptable percentage of reduction for 40.6 and 28.8 % of reduction for NIOSH 0500, and 22.7 and 27.3% for NIOSH 0600, respectively. The mathematical model from RSM shows promising strategy in term of control measures in protecting operators in SLS manufacturing industry from occupational exposures.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Muhamad Damanhuri, Amir Abdullah
author_facet	Muhamad Damanhuri, Amir Abdullah
author_sort	Muhamad Damanhuri, Amir Abdullah
title	PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
title_short	PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
title_full	PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
title_fullStr	PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
title_full_unstemmed	PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
title_sort	pa12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling
granting_institution	Universiti Tun Hussein Onn Malaysia
granting_department	Fakulti Kejuruteraan Mekanikal dan Pembuatan
publishDate	2021
url	http://eprints.uthm.edu.my/8397/1/24p%20AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI.pdf http://eprints.uthm.edu.my/8397/2/AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI%20COPYRIGHT%20DECLARATION.pdf http://eprints.uthm.edu.my/8397/3/AMIR%20ABDULLAH%20MUHAMAD%20DAMANHURI%20WATERMARK.pdf
_version_	1776103335999307776

PA12 nylon dust reduction of selective laser sintering reprocessing by optimization of refresh rate and powder handling

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