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Understanding Melting in Fused Filament Fabrication Process.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Understanding Melting in Fused Filament Fabrication Process./
作者:	Colon Quintana, Jose Luis.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	154 p.
附註:	Source: Dissertations Abstracts International, Volume: 83-03, Section: B.
Contained By:	Dissertations Abstracts International83-03B.
標題:	Mechanical engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28717696
ISBN:	9798535599779

Understanding Melting in Fused Filament Fabrication Process.
Colon Quintana, Jose Luis.

Understanding Melting in Fused Filament Fabrication Process. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 154 p.

Source: Dissertations Abstracts International, Volume: 83-03, Section: B.

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2021.

This item must not be sold to any third party vendors.

During the fused filament fabrication (FFF) process, understanding the melting mechanism is essential to model and predict the efficiency rate during extrusion. The efficiency rate is achieved when printing at the highest printing velocity possible without having any defect. Current FFF processes use low printing speeds to avoid under-extrusion and subsequently producing a faulty part. It is crucial to predict the feeding rate based on the material properties and its force to print at higher velocities successfully. The work presented here allows understanding the melting mechanisms during an FFF process and improves an existing model based on the results.The second chapter of the manuscript summarizes and discusses the state-of-the-art in the field of the FFF process. In particular, it discusses previous models analyzing the melting process and the prediction of filament velocity. For decades, a significant challenge in this process has been understanding and forecasting the printing speed of these machines. Hence, a fundamental part of this work proposal involves improving the melting models available in the present. In particular, the FFF melting model proposed by Osswald et al. [1] uses the concept of the pressure-induced melt removal process as its core.The third chapter, a theoretical background, provides the basic knowledge necessary to understand the work presented here.The fourth chapter focuses on understanding the base assumption of the pressured-induced melt removal process, backbone of the Osswald et al. model [1]. Experimental results were acquired and compared with analytical solutions and numerical simulations. Computed tomography technology was employed to visualize the melt film formation. An understanding of the melting temperature for amorphous materials was achieved. A distinguished transition on viscosity was observed for the amorphous materials suggesting that the melting temperature equals the glass transition temperature. Good prediction between all the methods was achieved. Results give insights into the melting phenomena of materials during the fused filament fabrication process.The fifth chapter shows an improvement performed to the Osswald et al. model [1]. The model is improved by taking into account the shear-thinning behavior of the polymer material by including the power-law model as the viscosity model. Equations, model as- sumptions, and considerations are explained in detail. The model shows good agreement with experimental results assuming that the melting temperature of both amorphous and semi-crystalline materials equal the glass transition temperature. For the semi-crystalline material, a comparison was made using the glass transition temperature and melting temperature. Moreover, a radiation heat transfer analysis was performed to account for the heating from the heated walls to the filament material.The sixth chapter studies radiation heat transfer and nozzle diameter on a range of melting models. The radiation heat transfer was implemented to both the Osswald et al. model and the improved Osswald et al. model. The radiation approach calculates the initial temperature of the filament as a function of filament velocity. Later, the melt film thickness is calculated and input into both melting models. The models are compared with experimental data obtained from a customized FFF machine. The data processed allowing the understanding of the critical force where slippage occurs. It was shown that the slippage would be dependent on the material properties and not the printing parameters. A good prediction was made when calculating the theoretical, critical force. It was shown that the improved Osswald et al. model approximates best the ABS data. However, this is not true when predicting the PLA data under the assumption of using the actual melting temperature (not the glass transition temperature). The results give insight into what models best describe the FFF process for a range of materials, nozzle diameters, and process temperature.Based on the measurements, concepts, and results, future work is proposed in Chapter 7. A suggested setup is presented to visualize the density difference between solid and melted material on a FFF machine during extrusion. It is proposed to use a different boundary condition on the Osswald et al. model and improved Osswald et al. model, which considers the velocity component in the r-direction. Also, it is suggested that experiments should be done to determine the contact area between the feeding mechanism and filament velocity for a range of FFF machines.

ISBN: 9798535599779Subjects--Topical Terms:

649730
Mechanical engineering.
Subjects--Index Terms:

Characterization

Understanding Melting in Fused Filament Fabrication Process.
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100 1 $a Colon Quintana, Jose Luis. $3 3681834
245 1 0 $a Understanding Melting in Fused Filament Fabrication Process.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2021
300 $a 154 p.
500 $a Source: Dissertations Abstracts International, Volume: 83-03, Section: B.
500 $a Advisor: Osswald, Tim.
502 $a Thesis (Ph.D.)--The University of Wisconsin - Madison, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a During the fused filament fabrication (FFF) process, understanding the melting mechanism is essential to model and predict the efficiency rate during extrusion. The efficiency rate is achieved when printing at the highest printing velocity possible without having any defect. Current FFF processes use low printing speeds to avoid under-extrusion and subsequently producing a faulty part. It is crucial to predict the feeding rate based on the material properties and its force to print at higher velocities successfully. The work presented here allows understanding the melting mechanisms during an FFF process and improves an existing model based on the results.The second chapter of the manuscript summarizes and discusses the state-of-the-art in the field of the FFF process. In particular, it discusses previous models analyzing the melting process and the prediction of filament velocity. For decades, a significant challenge in this process has been understanding and forecasting the printing speed of these machines. Hence, a fundamental part of this work proposal involves improving the melting models available in the present. In particular, the FFF melting model proposed by Osswald et al. [1] uses the concept of the pressure-induced melt removal process as its core.The third chapter, a theoretical background, provides the basic knowledge necessary to understand the work presented here.The fourth chapter focuses on understanding the base assumption of the pressured-induced melt removal process, backbone of the Osswald et al. model [1]. Experimental results were acquired and compared with analytical solutions and numerical simulations. Computed tomography technology was employed to visualize the melt film formation. An understanding of the melting temperature for amorphous materials was achieved. A distinguished transition on viscosity was observed for the amorphous materials suggesting that the melting temperature equals the glass transition temperature. Good prediction between all the methods was achieved. Results give insights into the melting phenomena of materials during the fused filament fabrication process.The fifth chapter shows an improvement performed to the Osswald et al. model [1]. The model is improved by taking into account the shear-thinning behavior of the polymer material by including the power-law model as the viscosity model. Equations, model as- sumptions, and considerations are explained in detail. The model shows good agreement with experimental results assuming that the melting temperature of both amorphous and semi-crystalline materials equal the glass transition temperature. For the semi-crystalline material, a comparison was made using the glass transition temperature and melting temperature. Moreover, a radiation heat transfer analysis was performed to account for the heating from the heated walls to the filament material.The sixth chapter studies radiation heat transfer and nozzle diameter on a range of melting models. The radiation heat transfer was implemented to both the Osswald et al. model and the improved Osswald et al. model. The radiation approach calculates the initial temperature of the filament as a function of filament velocity. Later, the melt film thickness is calculated and input into both melting models. The models are compared with experimental data obtained from a customized FFF machine. The data processed allowing the understanding of the critical force where slippage occurs. It was shown that the slippage would be dependent on the material properties and not the printing parameters. A good prediction was made when calculating the theoretical, critical force. It was shown that the improved Osswald et al. model approximates best the ABS data. However, this is not true when predicting the PLA data under the assumption of using the actual melting temperature (not the glass transition temperature). The results give insight into what models best describe the FFF process for a range of materials, nozzle diameters, and process temperature.Based on the measurements, concepts, and results, future work is proposed in Chapter 7. A suggested setup is presented to visualize the density difference between solid and melted material on a FFF machine during extrusion. It is proposed to use a different boundary condition on the Osswald et al. model and improved Osswald et al. model, which considers the velocity component in the r-direction. Also, it is suggested that experiments should be done to determine the contact area between the feeding mechanism and filament velocity for a range of FFF machines.
590 $a School code: 0262.
650 4 $a Mechanical engineering. $3 649730
650 4 $a Mechanical properties. $3 3549505
650 4 $a Polymers. $3 535398
650 4 $a Polyvinyl chloride. $3 686187
650 4 $a Simulation. $3 644748
650 4 $a Velocity. $3 3560495
650 4 $a Shear tests. $3 3681835
650 4 $a Viscosity. $3 1050706
650 4 $a Nozzle geometry. $3 3681836
650 4 $a Rheology. $3 570780
650 4 $a Temperature. $3 711968
650 4 $a Thermogravimetric analysis. $3 3681837
650 4 $a Heat conductivity. $3 3681489
650 4 $a Boundary conditions. $3 3560411
650 4 $a Shear strength. $3 3680813
650 4 $a Radiation. $3 673904
650 4 $a Shear stress. $3 3681838
653 $a Characterization
653 $a Fused filament fabrication
653 $a Force sensor and encoder
653 $a Melting model
653 $a Rheology
653 $a Slippage
690 $a 0548
710 2 $a The University of Wisconsin - Madison. $b Mechanical Engineering. $3 2094221
773 0 $t Dissertations Abstracts International $g 83-03B.
790 $a 0262
791 $a Ph.D.
792 $a 2021
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28717696