簡易檢索 / 詳目顯示

回結果列表
研究生： Hasan Syafik Maulana
Hasan Syafik Maulana
論文名稱： 以數值模擬探討熔融沉積成型式3D列印機內之速度﹑溫度與濃度場
A Numerical Study of the Velocity, Temperature, and Concentration Fields in a Fused Deposition Modeling 3D Printer
指導教授： 田維欣
Wei-Hsin Tien
口試委員: 田維欣
Wei-Hsin Tien
林怡均
Yi-Jiun Peter LIN
鄭逸琳
Yih-Lin Cheng
周振嘉
Chen-Chia Chou
學位類別： 碩士
Master
系所名稱： 工程學院 - 機械工程系
Department of Mechanical Engineering
論文出版年： 2018
畢業學年度： 106
語文別： 英文
論文頁數： 140
中文關鍵詞： 計算流體力學 、3D列印機 、熔融沉積成型 、微粒排放
外文關鍵詞： Computational fluid dynamic, 3D Printer, Fused Deposition Modeling, particle emission
相關次數： 點閱：391  下載：31 
分享至:
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報

    • 熔融沉積成型(Fused Deposition Modeling, FDM)式3D列印機是目前最受歡迎的積層製造技術之一。在列印過程中，FDM 3D列印機會釋放出高量之超微顆粒(ultrafine particle, UFP)與揮發性有機物(volatile organic compounds, VOCs)。這些物質來自於列印之線材，通常為熱塑性材料如ABS或PLA。兩種常用材料均有報告指出會在加熱列印過程中排放有害人體之物質，造成健康風險。在本研究中以有限體積法用標準紊流? – ?模型建構了一個市售FDM 3D 列印機之數值模型，探討機台內部之流場與熱質傳現象。在機台內部之兩加熱器分別位於噴頭與加熱底板，溫度維持在200 ℃ and 100 ℃，而噴頭冷卻模組之散熱風扇流量維持在0.0028 m^3/s。研究中探討了加熱器開關、加熱底板高度、噴嘴位置之影響。模擬結果顯示，來自於冷卻風扇之空氣流動對FDM 3D列印機內之流場影響甚鉅，經過冷卻熱沉造成側向噴流狀流動，最高速度達到 7 m/s。此流動影響了機內氣流之溫度分布並顯示其受強制對流之影響。為求進一步控制機台內部之汙染物排放，研究中提出使用推拉式氣簾系統，並以此數值模型進行初步驗證。驗證探討項目包括氣簾系統之效能受氣簾吹出之傾角、加熱底板高度與噴嘴移動位置之影響。此部分模擬結果顯示氣簾有傾角對控制微粒汙染之擴散有幫助，使得平均相對濃度由垂直氣簾之0.019降至傾斜氣簾之0.0016。而氣簾傾角維持在45°有最佳效果，機台前方監測點之濃度變化在0.0103 to 0.0326之間，大於45°時之汙染排放濃度則無明顯改善。氣簾在噴嘴模組移動時有較差之效能，因為其推與拉之氣簾流動整體性遭噴嘴之冷卻風扇噴流所破壞。

    Fused Deposition Modeling (FDM) 3D printer is one of the most popular additive manufacturing techniques. During the operation of a FDM 3D printer, it may emit high rate of ultrafine particle (UFP) and volatile organic compounds (VOCs). The UFP emission comes from ABS or PLA, the feedstock and product materials of FDM 3D printer. Both materials are confirmed to have health risk for the human body. In this study, a numerical model based on finite volume method and standard ? − ? turbulent model is established to investigate the flow, heat, and mass transfer inside the FDM 3D printers. The two heaters in the 3D printer are located at the nozzle unit and on the base plate, which are maintained at 200 ℃ and 100 ℃, respectively. The flow rate of the cooling fan is 0.0028 m^3/s. The effects of the heater and nozzle head conditions, the positions of the heater plate and printer head are investigated in this study. The simulation results show that the airflow from the cooling fan greatly influences the flow direction of the FDM 3D printer, causing a jet effect towards the side of the fin channel with maximum velocity about 7 m/s. The flow from cooling fan also influences the temperature distribution inside the FDM 3D printer, which indicates that the flow is dominated by forced convection. To further contain particle emissions, a push and pull air curtain system is proposed and evaluated with the numerical model. The effects of the push and pull system design, variation of inclined jet angle, and the positions of heater plate and printer head are investigated to understand the performance of the proposed push and pull air curtain system. The simulation results show that the push and pull system with inclined jets performs better than the straight one with regard to the movement of the printer head, with average concentration value up to 0.0119 kg/kg for straight curtain design and 0.0016 kg/kg for the inclined curtain design. The inclined angles of the push jets greater than 45° do not show significant improvements in terms of controlling particle emissions and the ones smaller than 45° have higher nominal concentration values in front of the heater plate, ranging from 0.0103 to 0.0326 kg/kg. The connectivity of the push and pull system is broken by the flow from cooling fan when the printer head passing through, which lowers the performance of the push and pull system.

    摘要 i ABSTRACT iii ACKNOWLEDGEMENTS v CONTENT vi NOMENCLATURES ix LIST OF TABLES xii LIST OF FIGURES xiii INTRODUCTION 1 1.1 Motivation 1 1.2 Literature Review 3 1.2.1 Emission of Ultrafine Particle by FDM 3D Printer 3 1.2.2 Computational Fluid Dynamic (CFD) Predictive of Flow, Heat, and Mass Transfer 6 1.2.3 Push and Pull Air Curtain System 7 1.3 Objective 9 1.4 Structure of Thesis 9 MATHEMATICAL FORMULAE AND NUMERICAL METHOD 11 2.1 Governing Equations 11 2.2 Eddy Viscosity Turbulence Model 12 2.3 Standard High Reynold Number k-ε Model 14 2.4 Simulation Software 17 2.5 Problem Descriptions 18 2.6 Grid Generation 20 RESULTS AND DISCUSSION 21 3.1 Flow and Heat Transfer Inside Fused Deposition Modeling (FDM) 3D Printer 21 3.1.1 Effect of Heat Source and Cooling Fan 22 3.1.2 Effect of The Height of the Heater Plate 25 3.1.3 Effect of Variation Nozzle Head Position 27 3.2 Flow and Mass Transfer Inside Fused Deposition Modeling (FDM) 3D Printer with Push and Pull System 30 3.2.1 Effect of Push and Pull System Model in Air Curtain System 31 3.2.2 Effect of Push System Angle in Air Curtain System 35 3.2.3 Effect of Heights of the Heater Plate in Air Curtain System 38 3.2.4 Effect of Printer Head Position in Air Curtain System 40 3.3 Discussions 42 3.3.1 Parameters That Affect the System Performance and Their Interactions 42 3.3.2 Limitations of This Study 43 CONCLUSIONS AND FUTURE WORKS 45 4.1 Conclusions 45 4.2 Future Work 47 BIBLIOGRAPHY 49 CURRICULUM VITAE 139

    1. marketsandmarkets.com. 3D Printing Market by Printer Type, Material Type (Metals, Plastics, Ceramics & Others), Material Form (Powder, Liquid, Filament), Process, Technology, Software, Service, Application, Vertical and Geography - Global Forecast to 2022. 2016 April 2016 [cited 2016 April]; Available from: http://www.marketsandmarkets.com/Market-Reports/3d-printing-market-1276.html.
    2. ISO/ASTM 52900:2015(E), Standard Terminology for Additive Manufacturing – General Principles –Terminology.
    3. J. Unwin, M. R. Coldwell, C. Keen, and J. J. McAlinden, Airborne emissions of carcinogens and respiratory sensitizers during thermal processing of plastics. Ann Occup Hyg, 2013. 57(3): p. 399-406.
    4. http://data.europa.eu/eli/reg/2008/1272/oj, European Commission (EC) Regulation No. 1272/2008 of the European Parliament and of the Council on classification, labelling and packaging of substances and mixtures. 2008.
    5. http://monographs.iarc.fr/ENG/Classification/latest_classif.php, International Agency for Research on Cancer (IARC) Monographs on the Evaluation of Carcinogenic Risk to Humans. 2017.
    6. B. Stephens, P. Azimi, Z. El Orch, and T. Ramos, Ultrafine particle emissions from desktop 3D printers. Atmospheric Environment, 2013. 79(1): p. 334-339.
    7. Yu Zhou, Xiangri Kong, Ailu Chen, and Shijie Cao, Investigation of Ultrafine Particle Emissions of Desktop 3D Printers in the Clean Room. Procedia Engineering, 2015. 121(1): p. 506-512.
    8. Y. Kim, C. Yoon, S. Ham, J. Park, S. Kim, O. Kwon, and P. J. Tsai, Emissions of Nanoparticles and Gaseous Material from 3D Printer Operation. Environ Sci Technol, 2015. 49(20): p. 12044-53.
    9. Y. L. Deng, S. J. Cao, A. L. Chen, and Y. S. Guo, The impact of manufacturing parameters on submicron particle emissions from a desktop 3D printer in the perspective of emission reduction. Building and Environment, 2016. 104: p. 311-319.
    10. P. Azimi, D. Zhao, C. Pouzet, N. E. Crain, and B. Stephens, Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments. Environ Sci Technol, 2016. 50(3): p. 1260-8.
    11. N. A. Mohajer, C. Y. Wu, T. Ladun, D. A. Rajon, and Y. Huang, Characterization of particulate matters and total VOC emissions from a binder jetting 3D printer. Building and Environment, 2015. 93(2): p. 293-301.
    12. Naoki Kagi, Shuji Fujii, Youhei Horiba, Norikazu Namiki, Yoshio Ohtani, Hitoshi Emi, Hajime Tamura, and Yong Shik Kim, Indoor air quality for chemical and ultrafine particle contaminants from printers. Building and Environment, 2007. 42(5): p. 1949-1954.
    13. J. Gao, Y. T. Jian, C. S. Cao, L. Chen, and X. Zhang, Indoor emission, dispersion and exposure of total particle-bound polycyclic aromatic hydrocarbons during cooking. Atmospheric Environment, 2015. 120(1): p. 191-199.
    14. L. Wallace, F. Wang, C. Howard-Reed, and A. Persily, Contribution of Gas and Electric Stoves to Residential Ultrafine Particle Concentrations between 2 and 64 nm: Size Distributions and Emission and Coagulation Rates. Environmental Science & Technology, 2008. 42(23): p. 8641-8647.
    15. B. Zamora and G. Sancho, Effects of heating intensity on the transient natural convection flows in open cavities. International Journal of Heat and Mass Transfer, 2016. 100: p. 861-875.
    16. I. V. Miroshnichenko, M. A. Sheremet, and A. A. Mohamad, Numerical simulation of a conjugate turbulent natural convection combined with surface thermal radiation in an enclosure with a heat source. International Journal of Thermal Sciences, 2016. 109: p. 172-181.
    17. M. J. Chern and W. Y. Cheng, Numerical investigation of turbulent diffusion in push-pull and exhaust fume cupboards. Ann Occup Hyg, 2007. 51(6): p. 517-31.
    18. R. F. Huang, S. Y. Lin, S. Y. Jan, R. H. Hsieh, Y. K. Chen, C. W. Chen, W. Y. Yeh, C. P. Chang, T. S. Shih, and C. C. Chen, Aerodynamic characteristics and design guidelines of push-pull ventilation systems. Ann Occup Hyg, 2005. 49(1): p. 1-15.
    19. R. F. Huang, Y. D. Wu, H. D. Chen, C. C. Chen, C. W. Chen, C. P. Chang, and T. S. Shih, Development and evaluation of an air-curtain fume cabinet with considerations of its aerodynamics. Ann Occup Hyg, 2007. 51(2): p. 189-206.
    20. Jia-Kun Chen, Rong Fung Huang, Pei-Yi Hsin, Ching Min Hsu, and Chun-Wann Chen, Flow and Containment Characteristics of an Air-curtain Fume Hood Operated at High Temperatures. Industrial Health, 2012. 50(2): p. 103-114.
    21. R. F. Huang and C. I. Chou, Flow and performance of an air-curtain biological safety cabinet. Ann Occup Hyg, 2009. 53(4): p. 425-40.
    22. Richard H. Kruse, William H. Puckett, and John H. Richardson, Biological safety cabinetry. Clinical Microbiology Reviews, 1991. 4(2): p. 207-241.
    23. S. C. Hu, A. Shiue, J. X. Tu, H. Y. Liu, and R. B. Chiu, Validation of cross-contamination control in biological safety cabinet for biotech/pharmaceutical manufacturing process. Environ Sci Pollut Res Int, 2015. 22(23): p. 19264-72.
    24. B. E. Launder and D. B. Spalding, The numerical computation of turbulent flows. Computer Methods in Applied Mechanics and Engineering, 1974. 3(2): p. 269-289.
    25. Mentor Graphics, FloVENT Background Theory Reference Guide, Software Version 11.2. 2016, Mentor Graphics Corporation.
    26. Jeff Kerns, 3D Printing Tips and Tech: Get to Know Those Acronyms. 2015, http://www.machinedesign.com.
    27. Markelapellaniz, Extrusion deposition: Fused Deposition Modeling (FDM). 2016, www.additive3d.com.

    QR CODE