Analysis and Optimization of Compression Glass Molds: Tumbler A Thesis Presented to The Faculty of the Fritz J. and Dolores H. Russ College of Engineering and Technology Ohio University In Partial Fulfillment of the Requirement for the Degree Master of Science by Edgardo E. Amable March, 1997 ACKNOWLEDGMENTS Thanks to Dr. Bhavin Mehta, my advisor, for his constant encouragement, advice, and recommendation in performing not only this project but also my academic life. Thanks to Dr. M.K. Alam, Professor of Mechanical Engineering for his effort in being part of the committee. '41~0I want to thank Dr. James Fales, chairman of the Department of Industrial 'Technology for his support, helpful encouragement and for all that I learned as a member of the Center for Automatic Identification. I want to dedicate this project to my parents and brothers in gratitude for their constant support during my academic life. Finally, I want to thank Anamaria for her understanding and caring, and for showing me that love is something that goes beyond the simple physical contact. Gracias! TABLE OF CONTENTS 1. INTRODUCTION AND STATEMENT OF THE PROBLEM .................................. 1 1.1. General introduction ..................................................................................... 1 1.2. Objective ....................................................................................................... 2 1.3. Glass .............................................................................................................2 1.3.1. What is glass ..................................................................................2 1.3.2. Flow at high temperatures .............................. ..........................4 1.3.3. Glass manufacturing ......................................................................7 1.3.4. General glass manufacturing methods ........................................... 9 1.3.5. Compression glass molding .......................................................... 9 1.3.5.1 . What is compression glass molding ............................... 9 1.4. Statement of the problem ............................................................................15 2 . BACKGROUND .......................................................................................................16 2.1 . Factors affecting mold design ..................................................................... 16 2.2. Thermal stresses on compression glass molds ........................................... 21 2.3. Previous studies for establishing optimal mold design .............................25 2.4. The finite element method ...................... .................................................34 3 . METHODOLOGY ...................................................................................................46 3.1. Description of the tumbler 176 ................................................................... 48 3.1.1. Soda-lime glasses ........................................................................ 48 3.2. 3-D solid modeling ..................................................................................... 49 3.2.1. Geometric modeling technique .................................................... 49 3.2.2. 3-D solid modeling of the tumbler- 176 molding equipment ....... 50 3.3 . Thermal stress analysis of the mold bottom and the plunger using Finite Element Method ...................................................................53 3.3.1. Application of the Finite Element Method .................................. 53 3.3.2. Preprocessing ...............................................................................54 3.3.3. The boundary conditions .............................................................56 3.3.4. Analysis runs. postprocessing. and optimization ........................57 4 . ANALYSIS OF RESULTS .......................................................................................58 4.1. Mold insert .................................................................................................58 4.2. Plunger ........................................................................................................60 5 . CONCLUSIONS AND RECOMMENDATIONS FOR FURTHER RESEARCH .. 65 5.1 Conclusions .................................................................................................65 5.1.1. Application of computer techniques to improve mold design ..... 65 5.1.2. System implementation feasibility ..............................................65 5.2. Recommendations for further research .......................................................67 5.2.1. Finite Element Analysis of the assembly model ....................... 67 5.2.2. Possibility of research on the glass forming process .................. 67 5.2.2.1. Viscoplastic behavior ...................................................67 5.2.2.2. Flow stress ...................................................................68 5.2.2.3. General method of analysis ........................................69 5.2.2.4. ANTARES ....................................................................72 REFERENCES ..............................................................................................................78 APPENDIX A: GLASS MANUFACTURING TECHNIQUES ...................................80 APPENDIX B: ANTARES 4.0 INPUT FOR COMPRESSION MOLDING ............... 87 LIST OF TABLES Table 2.1 . Manufacturing tolerances and glass design for pressed glassware .............. 20 Table 3- 1. Characteristics of the tumbler- 176 ............................................................... 47 Table 4.1 . Thermal structural stresses for various shapes analyzed ............................. 61 LIST OF FIGURES Figure 1.1 . Relationship between the viscosity and temperature of glass ..................... 6 Figure 1.2 . Flow diagram of a typical glass plant ........................................................... 8 Figure 1.3 . Pressed glass-mold types and pressing operations ..................................... 10 Figure 1.4 . Examples of pressed glassware ................................................................... 11 Figure 1.5 . Straight mold pressing process ................................................................... 14 Figure 2.1 . Linear element under thermal stresses ........................................................ 24 Figure 2.2 . Standard molds and new design .................................................................. 26 Figure 2.3 . Temperature distributions at the outside wall along the height .................. 27 Figure 2.4 . Nature of variation of heat flow and temperature depending on time ....... 32 Figure 2.5 . Finite elements ............................................................................................ 35 Figure 2.6 . Distribution of displacement u, temperature T, or fluid head ................. 37 Figure 2.7 . One-dimensional problems ......................................................................... 40 Figure 2.8 . Boundary conditions or constraints . Body with constraints ....................... 44 Figure 2.9 . Examples of boundary conditions. Beam with boundary conditions ......... 44 Figure 3. 1 . Tumbler- 176 molding equipment. Assembly drawing ............................... 47 Figure 3.2 . 3D solid modeling of the plunger ............................................................... 51 Figure 3.3 . 3D solid modeling of the mold insert ......................................................... 52 F igure 3.4 . Tetrahedral elements ................................................................................... 55 Figure 4.1 . Thermal structural stress distribution on the mold Insert .......................... 59 Figure 4.2 . Thermal structural stress distribution for various plunger shapes analyzed 74 Figure 4-3.Thermal structural stress distribution for an original model of a plunger .. 63 Figure 4.4 . Thermal structural stress distribution for an optimized model of a plunger 64 Figure 5.1 . Design for manufacturing of compression glass molds .............................. 66 Figure 5.2 . Forming of a Gudgeon pin .......................................................................... 70 FIgure 5.3 . Predicted grid distorsion during Gudgeon pin forming .............................. 71 Figure 5.4 . Simulation of the deformation and meshing steps for the molten glass ..... 74 Figure 5.5 . Flow stress contours of the molten glass during compression .................... 75 Figure A.1 . Hartford I.S. narrow neck blow and blow process ..................................... 82 Figure A.2 . Pressed glass .............................................................................................. 83 Figure A.3 . Ring roll casting machine .......................................................................... 84 Figure A.4 . 200-inch Telescope disk cast in 1934 ....................................................... 86 1. INTRODUCTION AND STATEMENT OF THE PROBLEM 1.1. General Introduction Anchor Hocking Glass Company, Lancaster, Ohio, is a division of Anchor Glass Inc., a major glass manufacturer in the United States. In the past decades the company has been developing mold design and manufacturing techniques by applying empirical methods. Studies in the field of glass molds and their effects on the final product have been done by several researchers in the past, based on field experiments with prototypes. Some of these previous studies established the need of computer applications