표제지
목차
국문요약 8
Abstract 10
1. 서론 16
2. 이론적 배경 19
2.1. 정밀주조 19
2.1.1. 정밀주조의 개요 19
2.1.2. 정밀주조의 분류 22
2.2. 적층제조 공정 26
2.2.1. 적층제조 공정의 개요 26
2.2.2. 적층제조 공정의 분류 28
2.3. 사출성형 39
2.4. 표면개질 41
2.4.1. 표면개질 종류 42
2.4.2. 표면개질에 따른 표면 특성 평가 44
3. 실험 방법 46
3.1. 설계 및 제작 47
3.1.1. 폴리머 몰드 표면개질 56
3.1.2. 왁스 사출 61
3.1.3. 정밀주조 64
3.2. 특성 평가 66
3.2.1. 표면개질에 따른 접촉각 및 표면 에너지 측정 66
3.2.2. 표면개질에 따른 몰드의 표면 경도 및 거칠기 측정 69
3.2.3. 냉각 방식과 몰드소재 따른 온도 및 냉각속도 측정 72
3.2.4. 표면개질에 따른 몰드별 왁스패턴 취출력 측정 73
4. 실험결과 및 고찰 74
4.1. 표면개질에 따른 젖음성 분석 74
4.2. 표면개질에 따른 접촉각 및 표면에너지 측정 결과 76
4.3. 표면개질에 따른 표면 경도 및 표면 거칠기 분석 결과 81
4.4. 표면개질에 따른 왁스패턴 취출력 분석 결과 86
4.5. 적층제조 폴리머 몰드 냉각 방식에 따른 냉각속도 분석 90
4.6. Moldflow 프로그램을 활용한 시뮬레이션 결과 93
5. 결론 97
6. 참고 문헌 99
Table. 1. Physical and mechanical properties of the materials used for wax pattern molds 52
Table. 2. Parameters of wax injection condition. 63
Table. 3. Slope angle of paraffin wax droplet on the surface modification polymer molds fabricated by selective laser sintering 75
Table. 4. Measured contact angles of paraffin wax droplet on surface-modified polymer molds using sessile droplet method 80
Table. 5. Measured surface hardness and average Ra values of the surface-modified polymer molds fabricated by sele... 83
Table. 6. Measured surface hardness and average Ra values of surface-modified polymer molds fabricated by selective... 85
Table. 7. Measured eject pressure values wax pattern from (a) UV coated and (b) Teflon coated polymer molds fabricat... 89
Fig. 1. Lost wax casting Process 24
Fig. 2. CO₂ mold Process 25
Fig. 3. Shaw Process 25
Fig. 4. Schematics of the FDM technology 33
Fig. 5. Schematics of the SLA technology 34
Fig. 6. Schematics of the SLS technology 35
Fig. 7. Schematics of the Materials jetting technology 36
Fig. 8. Schematics of the DMT technology 37
Fig. 9. Schematics of the CJP technology 38
Fig. 10. A schematic diagram of wax injection process 40
Fig. 11. A schematic diagram representing surface energy equlibrium and corresponding contact angle formed at the... 45
Fig. 12. Process flow charts for experimental procedures 46
Fig. 13. Design of the wax pattern for precision casting 49
Fig. 14. Schematics of the 3D model for the moldflow simulation 50
Fig. 15. Cooling systems for the comparison of the cooling performance 51
Fig. 16. Wax pattern molds fabricated by (a) Aluminium mold, (b) SLS using PA2200 as a mold... 53
Fig. 17. SLSed specimens for the analysis of the surface properties 54
Fig. 18. SLS Printer(EOS, EOS P3953D) 55
Fig. 19. Schematic diagrams of UV curing Acrylic resin coating process 58
Fig. 20. Schematic diagrams of the PVD process 59
Fig. 21. Schematic diagrams of the Teflon coating process 60
Fig. 22. Schematic diagram of wax injection process 62
Fig. 23. Lost wax casting process 65
Fig. 24. Digital hot air dry oven (HQ-FDO156) 67
Fig. 25. Contact angle measurements apparatus (KRUSS DSA10) 68
Fig. 26. Shore A scale measurement device: Shore A Durometer 100HA 70
Fig. 27. Surface roughness measurement apparatus: Olympus OLS 3100 71
Fig. 28. Evaluation process of the eject pressure of wax pattern 73
Fig. 29. Contact angle of paraffin wax droplet on the surface modification polymer molds fabricated by selective laser sintering 75
Fig. 30. Measured contact angles and calculated surface energy of DI water and Diiodomathane droplets on... 78
Fig. 31. Photographs showing contact angles of (a), (b), (c), (d) water and (e), (f), (g), (h)... 79
Fig. 32. Measured surface hardness and average Ra values of the surface-modified polymer molds fabricat... 82
Fig. 33. Measured surface hardness and average Ra values of the surface-modified polymer molds fabricated by... 84
Fig. 34. Measured eject pressure of wax pattern from (a) UV coated and (b) Teflon coated polymer molds fabrica... 87
Fig. 35. Measured eject pressure of wax pattern from (a) UV coated and (b) Teflon coated polymer molds fabricated... 88
Fig. 36. Temperature measurement results of PA and ABS molds with and without conformal cooling channels 91
Fig. 37. Temperature measurement results of polymer molds and wax patterns with and without conformal... 92
Fig. 38. Cooling behavior analysis results for wax pattern with respect to both mold materials and cooling methods 94
Fig. 39. Deformation analysis results for wax pattern with respect to mold materials 95
Fig. 40. Cooling curve of the polymer core with respect to three different types of cooling systems 96