CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. For using CFRP composite, the cutting and drilling process is necessary, and the study of optimal cutting conditions is very necess...
CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. For using CFRP composite, the cutting and drilling process is necessary, and the study of optimal cutting conditions is very necessary, too. This dissertation is a study on the optimal drilling conditions of CFRP composite with various drilling condition. For the drilling of each specimen with different stacking sequence, three kinds of quasi-isotropic specimen, [0°/45°/90°/-45°]_6S, [0₃°/45₃°/90₃°/-45₃°]_2S, [0_6°/45_6°/90_6°/-45_6°]_S, and orthotropic [0°/90°/0°/90°]_6S, [0₃°/90₃°/0₃°/90₃°]_2S, [0_6°/90_6°/0_6°/90_6°]_S were fabricated with different stacking angle. The drilling of these various specimens with different machining condition is performed. For finding the mechanical characteristics of the CFRP composite depend on the stacking angle, 3 point bending and transverse bending test are performed, which are very similar to drilling test, and with this result the relationship between initial peak load in this test and cutting force in drilling is compared and analyzed. For studying and finding the optimal drilling condition, with 4 kinds of 10 mm diameter drill, high speed, cemented carbide, Ti-A/N coated, and PCD drill, the drilling test of the composite with different staking sequences is performed. From this test results, the cutting force of the each drills, the roughness of the hole, and the inter laminar delamination of the exit area are measured. The relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48 ply specimen with the 8, 10, and 12mm cemented carbide drill. The following results are obtained with the above experiments. 1. The difference of cutting force is very small in the specimens with the same number of stacking and the different number of laminar, however the difference of cutting force between the quasi-isotropic and orthotropic specimen ; the cutting force of the quasi-isotropic is less than the orthotropic. 2. The drilling test result with high speed, TiA/N, cemented carbide and PCD drill shows that PCD drill has the best in the life of drill and cemented carbide drill has the smallest cutting force, excellent roughness at exit, and the smallest delamination. 3. The drilling experiment, which conditions are with the high speed drill, the quasi-isotropic specimen of stacking sequence, [0°/45°/90°/-45°]_6S, the cutting speeds, 31.4, 47.1, 62.8, and 78.5 m/min, and the feed speeds, 5, 10, 40, and 60mm/min, shows that the flank wear is decreasing as the feed speed is increasing, but increasing as the cutting speed is increasing. 4. The specimen with stacking sequence, [0°/45°/90°/-45°]_6S, which is stacked with each ply to the different direction have smaller cutting force and better cutting result than the [0_6°/45_6°/90_6°/-45_6°]_s which is stacked to the same direction. 5. In the 16 ply stack thickness the difference of cutting force depend on feed speed is very small but in 32 ply and 48 ply, very big as feed speed increase, and in the 8mm diameter drill, the change of thrust as the increment of feed speed is small, but as the drill diameter is increasing, the change of thrust is increasing with very big increment. 6. From the transverse static test, it shows that the initial peack load of the specimen with isotropic stacking sequence is bigger than orthotropic and also, from the drilling test, the isotropic has smaller cutting force and better cutting result than the orthotropic. From the both test results, these shows that the isotropic is more suitable for the cutting.
CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. For using CFRP composite, the cutting and drilling process is necessary, and the study of optimal cutting conditions is very necessary, too. This dissertation is a study on the optimal drilling conditions of CFRP composite with various drilling condition. For the drilling of each specimen with different stacking sequence, three kinds of quasi-isotropic specimen, [0°/45°/90°/-45°]_6S, [0₃°/45₃°/90₃°/-45₃°]_2S, [0_6°/45_6°/90_6°/-45_6°]_S, and orthotropic [0°/90°/0°/90°]_6S, [0₃°/90₃°/0₃°/90₃°]_2S, [0_6°/90_6°/0_6°/90_6°]_S were fabricated with different stacking angle. The drilling of these various specimens with different machining condition is performed. For finding the mechanical characteristics of the CFRP composite depend on the stacking angle, 3 point bending and transverse bending test are performed, which are very similar to drilling test, and with this result the relationship between initial peak load in this test and cutting force in drilling is compared and analyzed. For studying and finding the optimal drilling condition, with 4 kinds of 10 mm diameter drill, high speed, cemented carbide, Ti-A/N coated, and PCD drill, the drilling test of the composite with different staking sequences is performed. From this test results, the cutting force of the each drills, the roughness of the hole, and the inter laminar delamination of the exit area are measured. The relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48 ply specimen with the 8, 10, and 12mm cemented carbide drill. The following results are obtained with the above experiments. 1. The difference of cutting force is very small in the specimens with the same number of stacking and the different number of laminar, however the difference of cutting force between the quasi-isotropic and orthotropic specimen ; the cutting force of the quasi-isotropic is less than the orthotropic. 2. The drilling test result with high speed, TiA/N, cemented carbide and PCD drill shows that PCD drill has the best in the life of drill and cemented carbide drill has the smallest cutting force, excellent roughness at exit, and the smallest delamination. 3. The drilling experiment, which conditions are with the high speed drill, the quasi-isotropic specimen of stacking sequence, [0°/45°/90°/-45°]_6S, the cutting speeds, 31.4, 47.1, 62.8, and 78.5 m/min, and the feed speeds, 5, 10, 40, and 60mm/min, shows that the flank wear is decreasing as the feed speed is increasing, but increasing as the cutting speed is increasing. 4. The specimen with stacking sequence, [0°/45°/90°/-45°]_6S, which is stacked with each ply to the different direction have smaller cutting force and better cutting result than the [0_6°/45_6°/90_6°/-45_6°]_s which is stacked to the same direction. 5. In the 16 ply stack thickness the difference of cutting force depend on feed speed is very small but in 32 ply and 48 ply, very big as feed speed increase, and in the 8mm diameter drill, the change of thrust as the increment of feed speed is small, but as the drill diameter is increasing, the change of thrust is increasing with very big increment. 6. From the transverse static test, it shows that the initial peack load of the specimen with isotropic stacking sequence is bigger than orthotropic and also, from the drilling test, the isotropic has smaller cutting force and better cutting result than the orthotropic. From the both test results, these shows that the isotropic is more suitable for the cutting.
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#드릴가공 복합재료 적층구성 CFRP복합재료
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