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The printing of the complex shapes by DLP technology from the ceramic materials
Popek, Tomáš ; Roleček, Jakub (referee) ; Spusta, Tomáš (advisor)
This work is focused on the characteristics of advanced ceramics, the basic principles of the 3D printing, and the division of methods for the 3D printing of ceramic materials. It also discusses the removal of the binder from the printed samples, subsequent sintering, and associated TGA analysis and high-temperature dilatometry. Al2O3 ceramic powder was used to print ceramic components, from which two suspensions with a weight fill of 60 and 65 % were prepared. These components have been progressively subjected to TGA analysis and high-temperature dilatometry. The results of the two measurements were used to determine the debinding and sintering cycle. Debinding took place in a vacuum at 410 . As a result, the weights decreased to 63.91 ± 0.45% and 68.62 ± 1.08% of the original weights. The parts were sintered for 120 minutes at 1550 and then the relative densities were measured, which were 87.89 ± 1.05 % and 88.36 ± 0.81 %. The complex components were a turbine with a height of h = 4.4 mm and a diameter of d = 27 mm, a hexagon head screw with a length of 20 mm and an M8 thread, and a nut with a height of 6.5 mm and a width of 13 mm with an M8 thread.
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Optimization of a debinding procedure for objects prepared by 3D printing of the low loaded photopolymeric ceramic suspensions
Rotter, Marek ; Roleček, Jakub (referee) ; Spusta, Tomáš (advisor)
Digital Light Processing (DLP) is one of the additive manufacturing methods suitable for preparing ceramic objects. The most important part of this manufacturing process is debinding, which eliminates cracks and defects due to the controlled transport of organic additives from inside to outside. Optimization of the debinding procedure of green bodies from suspension with loading 33.6 vol.% ZrO2 was accomplished for obtaining samples with maximal density and minimum defects. Samples with dimensions 14x14x15 mm were divided into nine groups with unequal debinding procedures. Each group has different heating rates (three heating rates) and atmosphere types (air, nitrogen, vacuum). The group contains six samples with wall thicknesses of 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm and 4.0 mm. Overall 54 samples were obtained. Evaluation of debinding groups included mass loss after debinding, after sintering and whole mass loss, visual observation of defects, calculation of relative density and porosity and shrinkage of samples. The most optimal debinding procedure takes 12 hours 30 min and it was performed under a vacuum. The average relative density of prepared samples was 98.4 ± 0.1 % and hardness HV1 was 1366 ± 17. Shrinkage in the cross-sectional direction reached 28 %, respectively 29 % in the printing direction. If stress concentrators are eliminated, this cycle provides good samples with 1 – 3 mm thick walls.
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The printing of the complex shapes by DLP technology from the ceramic materials
Popek, Tomáš ; Roleček, Jakub (referee) ; Spusta, Tomáš (advisor)
This work is focused on the characteristics of advanced ceramics, the basic principles of the 3D printing, and the division of methods for the 3D printing of ceramic materials. It also discusses the removal of the binder from the printed samples, subsequent sintering, and associated TGA analysis and high-temperature dilatometry. Al2O3 ceramic powder was used to print ceramic components, from which two suspensions with a weight fill of 60 and 65 % were prepared. These components have been progressively subjected to TGA analysis and high-temperature dilatometry. The results of the two measurements were used to determine the debinding and sintering cycle. Debinding took place in a vacuum at 410 . As a result, the weights decreased to 63.91 ± 0.45% and 68.62 ± 1.08% of the original weights. The parts were sintered for 120 minutes at 1550 and then the relative densities were measured, which were 87.89 ± 1.05 % and 88.36 ± 0.81 %. The complex components were a turbine with a height of h = 4.4 mm and a diameter of d = 27 mm, a hexagon head screw with a length of 20 mm and an M8 thread, and a nut with a height of 6.5 mm and a width of 13 mm with an M8 thread.
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