國立台灣科技大學 機械工程系 博士學位論文 學號：D9803807 Research on Surface Finish Improvement Using Abrasive Jet Polishing, Annealing, and Air-Driving Fluid Jet Polishing Processes 研 究 生 ：Pham Huu Loc 指導教授：修芳仲 博士 中華民國 101 年 12 月 14 日 Research on Surface Finish Improvement Using Abrasive Jet Polishing, Annealing, and Air-Driving Fluid Jet Polishing Processes by Pham Huu Loc Department of Mechanical Engineering National Taiwan University of Science and Technology ABSTRACT Surface finish plays an important role in product quality due to its direct effects on product appearance. Hence, improvement of the surface finish is an essential requirement in industrial products. In an attempt to improve the surface finish of bulk metallic glass (BMG) material, some common methods have been used, such as milling, grinding, and lapping. However, the BMG surface finish has not yet been significantly improved by using these methods.
Therefore, this thesis proposes sequential abrasive jet polishing (AJP) and annealing processes that can considerably improve the BMG surface finish. In addition, this thesis also takes into account optimal parameters for both the AJP and annealing processes based on the Taguchi’s L18 and L8 orthogonal array experimental results, respectively. The experimental results show that using the optimal AJP parameters, the surface roughness (Ra) of the ground BMG can be significantly improved from 0. After the AJP process, the surface roughness (Ra) of the polished BMG can be further improved from 5.7 to 2 nm within an area of 5×5 µm by using the optimal annealing parameters.
i Furthermore, this thesis also proposes both air-driving fluid jet polishing (FJP) and AJP process that can improve the surface roughness of N-BK7 optical glass. In addition, this thesis also investigates optimal parameters for air-driving FJP and AJP processes based on the Taguchi’s L18 orthogonal array experimental results. The surface roughness (Ra) of ground N-BK7 optical glass can be improved from 0.032 µm by using the optimal air-driving FJP parameters and improved from 0.018 µm by using the optimal AJP parameters. Finally, the determined optimal plane parameters for the air- driving FJP and the AJP are applied to the freeform surface finish of an N-BK7 spherical lens, and the surface roughness (Ra) of the spherical lens can be improved from 0.202 µm within an area of 283.6×200 µm by using the optimal plane air-driving FJP parameters and improved from 0.232 µm within an area of 283.6×200 µm by using the optimal plane AJP parameters.
Keywords: Abrasive jet polishing; Air-driving fluid jet polishing; Bulk metallic glass; Optical glass; Taguchi’s method; Annealing; Surface roughness. ii ACKNOWLEDGEMENTS First, I would like to express my sincerest gratitude to my advisor, Fang-Jung Shiou, Professor, Mechanical Engineering Department Chair, Director of Opto-Mechatronics Technology Center in National Taiwan University of Science and Technology, who has supported me throughout my thesis with his patience and knowledge. Besides my advisor, I would also like to thank the rest of my thesis committee for the valuable comments. In addition, I would also like to thank Professor Jason S.
Jang of National Central University and Professor Jinn P. Chu of National Taiwan University of Science and Technology for providing samples of BMG material used in this study. Furthermore, I am also grateful to Dr. Arif and teacher Sun-Peng Lin, who guided me in operating the CNC machining center in the workshop.
In addition, I would also like to express my appreciation and thank Mr. Assefa and Mr. Dang who helped me in all the time of research and writing of this thesis. Their assistance and guidance have been of great value in this study.
I would also like to express my appreciation to the Instrument Technology Research Center (ITRC), National Applied Research Laboratories, Hsinchu Science Park for providing the financially support and thank Dr. Wei-Yao Hsu, Mr. Zong-Ru Yu and ITRC staffs for helping me during my studying time. In my daily work, I am indebted to many of my other lab mates to provide me a happy and peaceful environment.
I would also like to thank the Library staffs who helped me in gathering a lot of information for this study. I am also very appreciative of the NTUST for providing the financial support from Sept., 2009 to August, 2012 during iii Ph. I offer my regards to all of those who supported me in any respect during my studying time. Finally, I would also like to thank my family for everything they have done for me.
Without their love, this thesis would not be finished. iv TABLE OF CONTENTS ABSTRACT. iii TABLE OF CONTENTS. v LIST OF FIGURES.
ix LIST OF TABLES. xiii CHAPTER 1 INTRODUCTION .1 Background about the development and application of BMG .1 The properties and machining ability of BMG.2 The properties and machining ability of optical glass .3 Abrasive jet polishing and air-driving fluid jet polishing process .3 Research motivation and thesis objectives .4 Outline of thesis. 7 CHAPTER 2 BASIC PRINCIPLE .1 Production of bulk metallic glass .4 Abrasive jet polishing process .2 AJP process Parameters .5 Air-driving fluid jet polishing process .2 Control factors and noise factors .4 Analysis of variance (ANOVA) and S/N ratio analysis. 30 CHAPTER 3 DEVELOPMENT OF AN AJP AND AN AIR-DRIVING FJP SYSTEM .1 Abrasive jet polishing system.2 Air-driving FJP polishing system .3 Velocity measurement system in AJP process .4 Velocity measurement system in air-driving FJP process.
44 CHAPTER 4 EXPERIMENTAL WORK .1 Material of the test specimens .1 Experimental setup of the AJP process .2 Experimental setup of the air-driving FJP process. Configuration of Taguchi’s orthogonal array .1 AJP process on BMG material .2 Annealing process on BMG material .3 Air-driving FJP process on N-BK7 optical glass .4 AJP process on N-BK7 optical glass. 68 CHAPTER 5 EXPERIMENTAL RESULTS AND DISCUSSION .1 Experimental results for the AJP process on ground BMG .1 Combination of the optimal level for each factor. Analysis of variance .4 Influence of pressure on the surface roughness .5 Influence of impact angle on the surface roughness .6 Influence of particle size on the surface roughness .7 Influence of polishing time on the surface roughness .8 Influence of abrasive material type on the surface roughness .9 Influence of standoff distance on the surface roughness .2 Experimental results of the annealing process on polished BMG .1 Combination of the optimal level for each factor .3 Experimental results for the air-driving FJP process on ground N-BK7 optical glass .1 Combination of the optimal level for each factor .3 Analysis of variance .4 Influence of air pressure on the surface roughness .5 Influence of polishing time on the surface roughness .6 Influence of impact angle on the surface roughness .4 Experimental results for the AJP process on ground N-BK7 .1 Combination of the optimal level for each factor .3 Analysis of variance .4 Influence of abrasive concentration on the surface roughness .5 Influence of impact angle on the surface roughness .6 Influence of pressure on the surface roughness.
99 vii CHAPTER 6 APPLICATION AND COMPARISON OF AIR-DRIVING FJP AND AJP FOR THE SURFACE FINISH OF N-BK7 OPTICAL GLASS .1 Comparison of the air-driving FJP and the AJP for the surface finish of N-BK7 optical glass .2 Application of the air-driving FJP and AJP .1 Application of the air-driving FJP .1 Application of AJP. 106 CHAPTER 7 CONCLUSIONS AND FUTURE WORK. 125 viii LIST OF FIGURES Fig.a Schematic illustration of the melt spinning process [4] .b Schematic diagram of the high-pressure die casting equipment designed and used by Inoue [4] .a Surface grinding machine [25] .b Principle of the grinding process [26] .3 Single Sided Lapping Set-Up [28].4 Variables in AJP technology [12] .5 Schematic diagram of AJP technology .7 The process of material removal in brittle material mode [29] .8 The process of material removal in ductile material mode [30] .9 Schematic diagram of the air-driving FJP .10 Steps of Taguchi’s method to determinate the optimal parameters.11 The illustration of the control and noise factors .1 Schematic illustration of AJP system .2 The tank, stirring device in (a) rest state (b) in process .3 The inverter control pump .4 Photo of the developed components of the AJP tool head .5 The container with some of outlets.6 Slurry within the tank (a) without mixed hydraulic oil and (b) with mixed hydraulic oil after 2 hours of the AJP process .7 Photo of the used 3-axis machining center, type MV-3A .8 Schematic illustration of the air-driving FJP system [20] .9 Photo of the tank .10 Photo of the air pressure regulator .11 Photo of the atomizer and nozzle .12 Cross section drawing of the nozzle .13 Photo of the developed air-driving FJP tool head .14 Photo of the air compressor, type Unoair .15 Schematic diagram of experimental setup for measuring the flow rate of slurry .16 Plot of slurry velocity as function of pressure. The best fit equation is v = 4.17 Plot of slurry velocity as function of pressure.
The best fit equation is v = 17.18 Photo of the experimental setup for measuring slurry flow rate in air-driving FJP .19 Photo of the experimental setup for measuring air flow rate in air-driving FJP 45 Fig.20 Plot of air velocity as function of pressure. The best fit equation is v = 2.21 Plot of slurry velocity as function of pressure. The best fit equation is v = 0.22 Plots of air flow rate. The best fit equation is Q = 0.23 Plots of slurry flow rate.
The best fit equation is Q = 0.1 The procedure to determine optimal parameters of AJP, air-driving FJP, and annealing processes .2 Photo of the Zr-based BMG .3 Photo of the N-BK7 .4 DSC plots of (Zr48Cu36Al8Ag8)99.75 amorphous alloy with heating rate of 40 °C/min .5 Photo of the fixture for N-BK7.6 Experimental setup for AJP .7 Experimental setup for air-driving FJP .8 Relationship between the material removal and the impact angle [10] .9 Tool path for polishing area of each trial .10 Investigation of slurry concentration on N-BK7 [21] .11 Investigation of standoff distance on N-BK7 [21] .12 The relationship between material removal and pressure .13 Tool path for polishing area of each trial .1 The plots of the control factor effects in the AJP process .2 Measured polishing force under the optimal AJP parameters .3 SEM images of a a ground surface and b a polished surface after using optimal AJP parameters .4 AFM analysis of a ground surface within an area of 50×50 µm: a 3D Profile and b surface roughness .5 AFM analysis of a polished surface within an area of 50×50 µm using optimal AJP parameters: a 3D Profile and b surface roughness .6 Influence of SiC abrasive particle size on the polished surface roughness .7 Influence of standoff distance on the polished surface roughness .8 The plots of the control factor effects in the annealing process .9 AFM images of: a a polished surface and b an annealed surface after using optimal annealing parameters within an area of 5×5 µm .10 The plots of the control factor effects in the air-driving FJP.11 Color 3D laser scanning microscope images of: a a ground surface and b a polished surface .12 Influence of air pressure on the polished surface roughness .13 Influence of polishing time on the polished surface roughness.14 Influence of impact angle on the polished surface roughness .15 The plots of the control factor effects in the AJP .16 A 3-D surface roughness topography of an NBK-7ground surface .17 A 3-D surface roughness topography of an N-BK7 polished surface .18 Influence of abrasive concentration on the polished surface roughness .19 Influence of impact angle on the polished surface roughness .20 Influence of pressure on the polished surface roughness .1 The spherical lens model with radius of curvature R=400 mm .2 Photo of a ground surface and polished surface on the N-BK7 spherical lens using the air-driving FJP .3 A 3-D surface roughness topography of a ground surface .4 A 3-D surface roughness topography of a polished surface using .