MODELLING OF POWDER DIE COMPACTION
CONTENTS 1 INTRODUCTION 1 1 TREATMENT OF MAIN SUBJECTS IN COMPACTION MODELLING 1 2 SUMMARIES OF INDIVIDUAL CHAPTERS 2 MODELLING AND PART MANUFACTURE 2 1 INTRODUCTION 2 2 REQUIREMENTS FOR IMPROVING THE PM PRODUCTION PROCESS 2 2 1 INTRODUCTION 2 2 2 SELECTION OF POWDER BLENDS 2 2 3 TOOLING DESIGN 2 2 4 PRESS SELECTION 2 2 5 PRODUCTION AND QUALITY CONTROL 2 2 6 SINTERING AND INFILTRATION 2 3 REQUIREMENTS FOR COMPACTION MODELLING 2 3 1 INPUT-DATA GENERATION 2 3 2 MODELLING AND PART MANUFACTURE: REQUIREMENTS OF THE HARDMETAL INDUSTRY (“HM”) 2 3 3 MODELLING AND PARTS MANUFACTURE: REQUIREMENTS OF FERROUS STRUCTURAL (“FS”) PARTS INDUSTRY 2 3 4 VALIDATION REFERENCES…… 3 MECHANICS OF POWDER COMPACTION 3 1 INTRODUCTION 3 2 UNIAXIAL DEFORMATION 3 3 DEFORMATION UNDER MULTIAXIAL STATES OF STRESS REFERENCES 4 COMPACTION MODELS 4 1 MICROMECHANICAL COMPACTION MODELS 4 1 1 STAGE 0 MODELS 4 1 2 STAGE 1 MODELS 4 1 3 STAGE 2 MODELS 4 2 PHENOMENOLOGICAL COMPACTION MODELS 4 2 1 INTRODUCTION 4 2 2 CAP MODEL 4 2 3 CAM-CLAY MODEL 4 3 CLOSURE… 5 MODEL INPUT DATA – ELASTIC PROPERTIES 5 1 INTRODUCTION 5 2 ELASTIC MODEL 5 3 EXPERIMENTAL TECHNIQUES 5 3 1 CHARACTERISATION OF ELASTIC PROPERTIES OF GREEN COMPACTED SAMPLES 5 3 2 CHARACTERISATION OF ELASTIC PROPERTIES AT HIGH STRESSES 5 4 CONCLUSIONS 6 MODEL INPUT DATA – PLASTIC PROPERTIES 6 1 INTRODUCTION 6 2 CLOSED-DIE COMPACTION TEST 6 2 1 DISCUSSION OF ASSUMPTIONS A1,A2,A3 6 2 2 INFLUENCE OF THE SAMPLE ASPECT RATIO ON EXPERIMENTAL RESULTS 6 3 POWDER CHARACTERISATION FROM TRIAXIAL TEST 6 4 CONCLUDING COMMENTS 7 MODEL INPUT DATA – FAILURE 7 1 INTRODUCTION 7 2 TENSILE TEST 7 3 DIAMETRAL COMPRESSION TEST 7 4 SIMPLE COMPRESSION TEST 7 5 CONCLUDING COMMENTS REFERENCES……………………………………………………………………… 8 FRICTION AND ITS MEASUREMENT IN POWDER-COMPACTION PROCESSES 8 1 INTRODUCTION 8 2 FRICTION MEASUREMENT BY AN INSTRUMENTED DIE 8 3 FRICTION MEASUREMENT BY A SHEAR PLATE 8 4 EXAMPLE MEASUREMENTS 8 4 1 INSTRUMENTED-DIE MEASUREMENTS 8 4 2 SHEAR-PLATE EXPERIMENTS 8 5 FACTORS THAT AFFECT FRICTION BEHAVIOUR 8 5 1 SURFACE PROPERTIES 8 5 2 COMPACT AND PROCESS INFLUENCES 8 6 OTHER FRICTION MEASUREMENT METHODS 8 7 RELEVANT BIBLIOGRAPHY 8 8 CONCLUDING COMMENTS CHAPTER BIBLIOGRAPHY 9 DIE FILL AND POWDER TRANSFER 9 1 INTRODUCTION 9 2 POTENTIAL SIGIFICANCE OF DIE FILL DENSITY DISTRIBUTION 9 3 DIE-FILLING RIG 9 4 THE FLOW BEHAVIOUR OF POWDER INTO DIES CONTAINING STEP-LIKE FEATURES 9 5 METALLOGRAPHIC TECHNIQUES FOR DETERMINING DENSITY VARIATIONS 9 6 MEASUREMENT OF DIE FILL DENSITY DISTRIBUTION BY X-RAY COMPUTERISED TOMOGRAPHY 9 6 1 HARDWARE COMPONENTS NEEDED FOR X-RAY CT 9 6 2 TECHNIQUE FOR THE QUANTITATIVE MEASUREMENT OF DENSITY VARIATIONS 9 6 3 RESULTS FOR DIE FILL DENSITY DISTRIBUTION USING X-RAY COMPUTERISED TOMOGRAPHY 9 7 MODELLING OF DIE FILLING 9 8 CONCLUDING COMMENTS 10 CALIBRATION OF COMPACTION MODELS 10 1 INTRODUCTION 10 2 CALIBRATION OF THE DRUCKER-PRAGER CAP MODEL 10 2 1 ELASTICITY 10 2 2 CALIBRATION OF YIELD STRESS SURFACE AND PLASTIC STRAIN METHOD BASED ON SIMPLE TESTS 10 3 CALIBRATION OF THE CAM-CLAY MODEL 10 4 CALIBRATION OF THE DRUCKER-PRAGER CAP MODEL FROM TRIAXIAL DATA 10 5 COMPARISON OF THE TWO CALIBRATIONS 10 6 CONCLUDING COMMENTS 11 PRODUCTION OF CASE-STUDY COMPONENTS 11 1 INTRODUCTION 11 2 PRESS INSTRUMENTATION FOR FORCE AND DISPLACEMENT 11 2 1 PUNCH FORCE 11 2 2 PUNCH TRAVEL 11 3 SIDE EFFECTS OF LOAD BUILDUP – PRESS AND PUNCH DEFLECTIONS 11 3 1 PRESS DEFLECTIONS 11 3 2 PUNCH DEFLECTIONS 11 3 3 IMPLICATIONS FOR THE ACQUIRED POSITION VALUES 11 3 4 CONCLUDING COMMENTS ON SYSTEM DEFLECTIONS 11 4 CASE-STUDY COMPONENTS 12 ASSESSING POWDER COMPACTS 12 1 INTRODUCTION 12 2 DENSITY DISTRIBUTION BY THE ARCHIMEDES METHOD 12 2 1 HARDMETALS 12 2 2 ZIRCONIA AND SM-CO SAMPLES 12 3 DENSITY DETERMINATION BY MACHINING 12 4 DENSITY DISTRIBUTION DETERMINED BY SEM-EDS LINE SCAN OF POLISHED CROSS-SECTIONS 12 4 1 GENERAL CONSIDERATIONS ON DENSITY MEASUREMENTS OF GREEN SAMPLES 12 4 2 SAMPLES 12 4 3 EXPERIMENTAL PROCEDURE 12 4 4 SEM-EDS METHOD TO DETERMINE DENSITY DISTRIBUTION 12 4 5 RESULTS 12 4 6 DISCUSSION AND CONCLUSION 12 5 DENSITY DETERMINATION BY X-RAY COMPUTERISED TOMOGRAPHY 12 6 COMPARISON OF RESULT OF DENSITY DISTRIBUTION MEASUREMENT TECHNIQUES 12 7 DETERMINATION OF DEFECT DISTRIBUTION 12 8 CONCLUDING COMMENTS 13 CASE STUDIES: DISCUSSION AND GUIDELINES 13 1 INTRODUCTION 13 2 CONSTITUTIVE PARAMETERS SENSITIVITY 13 2 1 CASE STUDY 3 13 2 2 CONSTITUTIVE MODEL USED FOR THE PARAMETER STUDY 13 2 3 INFLUENCE OF THE CONSTITUTIVE PARAMETER R 13 2 4 INFLUENCE OF THE HARDENING FOR HIGH DENSITY VALUES 13 2 5 LOOKING FOR GOOD AGREEMENT WITH EXPERIMENTAL VALUES 13 2 6 DISCUSSION 13 3 FRAMEWORK FOR THE NUMERICAL SIMULATION 13 4 INFLUENCE OF MESHING 13 5 INFLUENCE OF THE INITIAL AND PROCESS DATA 13 5 1 REFERENCE CASE 13 5 2 INFLUENCE OF THE FILL DENSITY DISTRIBUTION 13 5 3 INFLUENCE OF THE PUNCH KINEMATICS 13 5 4 DISCUSSION 13 6 CONCLUSIONS AND GUIDELINE 14 MODELLING DIE COMPACTION IN THE PHARMACEUTICAL INDUSTRY 14 1 INTRODUCTION 14 2 PHARMACEUTICAL FORMULATIONS AND PROCESSES 14 3 ROTARY TABLET PRESS PRODUCTION CYCLE 14 3 1 DIE FILL ON ROTARY PRESSES 14 3 2 COMPRESSION AND EJECTION 14 4 TABLET COMPACTION MODELLING 14 4 1 MATERIAL CHARACTERISATION FOR MODEL INPUT 14 4 2 FRICTION 14 5 CASE STUDIES 14 5 1 CASE STUDY 1: THE DENSITY DISTRIBUTION IN CURVED-FACED TABLETS 14 5 2 CASE STUDY 2: THE DENSITY DISTRIBUTION IN BI-LAYER TABLETS 14 5 3 CASE STUDY 3: THE DENSITY DISTRIBUTION IN COMPRESSION COATED TABLETS 14 6 SUMMARY AND CONCLUSIONS 14 7 ACKNOWLEDGEMENTS 15 APPLICATIONS IN INDUSTRY 15 1 NUMERICAL SIMULATION OF DIE COMPACTION AND SINTERING OF HARDMETAL DRILL TIPS 15 1 1 SUMMARY 15 1 2 INTRODUCTION 15 1 3 NUMERICAL SIMULATION OF DIE COMPACTION 15 1 4 NUMERICAL SIMULATION OF SINTERING 15 1 5 DISCUSSION AND CONCLUSIONS 15 2 CERAMIC CASE STUDIES 15 3 CONCLUDING COMMENTS