This paper presents initial development of polymer application. PNC materials containing a polyamide （PA） and nano to improve the mechanical properties. Commercial polyamide 6 nanocomposites （PNC） material for rap...This paper presents initial development of polymer application. PNC materials containing a polyamide （PA） and nano to improve the mechanical properties. Commercial polyamide 6 nanocomposites （PNC） material for rapid manufacturing （RM） particles （5 wt%） were produced by solution blending with the aim （PA6） was dissolved in formic acid （HCO2H） together with two different types of nano particle materials： yttrium stabilised zirconia （YSZ） and Hectorite clay （Benton 166） and spray-dried to create powder, creating powder with particle sizes in the range of 10-40 μm. The materials were processed on a CO2 selective laser sintering （SLS） experimental machine. Mechanical properties of the PNCs were evaluated and the results were compared with the unfilled base polymer. Good dispersion of additives was achieved by solution blending, however the PA6 was degraded during the material preparation and spray drying process which resulted in the formation of porous structure and low strength. However the addition of 5 （wt%） nano particles in the PA6 has shown to increase strength by an average of 50-60%. Further work on powder preparation is required in order to fully realize these performance benefits.展开更多
Direct slicing from GAD models to generate sectional contours of the part to be sintered for Selective Laser Sintering （SLS） may overcome inherent disadvantages of using a Stereo Lithography （STL） format. In this ...Direct slicing from GAD models to generate sectional contours of the part to be sintered for Selective Laser Sintering （SLS） may overcome inherent disadvantages of using a Stereo Lithography （STL） format. In this paper, a direct slicing procedure is proposed for Selective Laser Sintering based on material performance and process parameters. Slicing thickness depends on the 3 D geometric model, material performance and process parameters. The relationship among material performance, process parameters and the largest slicing thickness is established using analysis of a sintering temperature field. A dynamic linked library is developed to realize direct slicing from a CAD model.展开更多
Selective laser sintering （SLS） is a new process to prepare the polystyrene （PS）/Al2O3 nanocomposites. In this paper, with different laser power and other processing parameters unchanged, the morphology, density a...Selective laser sintering （SLS） is a new process to prepare the polystyrene （PS）/Al2O3 nanocomposites. In this paper, with different laser power and other processing parameters unchanged, the morphology, density and mechanical properties of the sintered specimens were investigated. It was found that nano-sized inorganic particles are uniformly located in the PS matrix and the maximum density of the sintered specimens with pure PS powder reaches 1.07 g/cm^3, higher than 1.04 g/cm^3 that of the sintered specimens with mixture powder. Due to strengthening and toughness of the nano-sized Al2O3 inorganic particles, the maximum notched impact strength and tensile strength of the sintered part mixed with nano-sized inorganic particles are improved greatly from 7.5 to 12.1 kJ/m^2 and from 6.5 to 31.2 MPa, respectively, under the same sintering condition.展开更多
In order to improve parts accuracy, a method of adding heat balance support （HBS） was proposed, and the detailed algorithm for generating HBS was developed. A number of experiments and a comparison between similar s...In order to improve parts accuracy, a method of adding heat balance support （HBS） was proposed, and the detailed algorithm for generating HBS was developed. A number of experiments and a comparison between similar softwares, showed that the algorithm is efficient and feasible. Moreover, different features of riBS were studied for different kinds of materials, such as PS and nylon. The research findings indicate that automatically adding HBS can significantly improve the accuracy of the parts, and that the algorithm for generating HBS is efficient and precise.展开更多
文摘This paper presents initial development of polymer application. PNC materials containing a polyamide （PA） and nano to improve the mechanical properties. Commercial polyamide 6 nanocomposites （PNC） material for rapid manufacturing （RM） particles （5 wt%） were produced by solution blending with the aim （PA6） was dissolved in formic acid （HCO2H） together with two different types of nano particle materials： yttrium stabilised zirconia （YSZ） and Hectorite clay （Benton 166） and spray-dried to create powder, creating powder with particle sizes in the range of 10-40 μm. The materials were processed on a CO2 selective laser sintering （SLS） experimental machine. Mechanical properties of the PNCs were evaluated and the results were compared with the unfilled base polymer. Good dispersion of additives was achieved by solution blending, however the PA6 was degraded during the material preparation and spray drying process which resulted in the formation of porous structure and low strength. However the addition of 5 （wt%） nano particles in the PA6 has shown to increase strength by an average of 50-60%. Further work on powder preparation is required in order to fully realize these performance benefits.
文摘Direct slicing from GAD models to generate sectional contours of the part to be sintered for Selective Laser Sintering （SLS） may overcome inherent disadvantages of using a Stereo Lithography （STL） format. In this paper, a direct slicing procedure is proposed for Selective Laser Sintering based on material performance and process parameters. Slicing thickness depends on the 3 D geometric model, material performance and process parameters. The relationship among material performance, process parameters and the largest slicing thickness is established using analysis of a sintering temperature field. A dynamic linked library is developed to realize direct slicing from a CAD model.
文摘Selective laser sintering （SLS） is a new process to prepare the polystyrene （PS）/Al2O3 nanocomposites. In this paper, with different laser power and other processing parameters unchanged, the morphology, density and mechanical properties of the sintered specimens were investigated. It was found that nano-sized inorganic particles are uniformly located in the PS matrix and the maximum density of the sintered specimens with pure PS powder reaches 1.07 g/cm^3, higher than 1.04 g/cm^3 that of the sintered specimens with mixture powder. Due to strengthening and toughness of the nano-sized Al2O3 inorganic particles, the maximum notched impact strength and tensile strength of the sintered part mixed with nano-sized inorganic particles are improved greatly from 7.5 to 12.1 kJ/m^2 and from 6.5 to 31.2 MPa, respectively, under the same sintering condition.
基金supported by the Innovatory Group Program of the Natural Science Foundation of Hubei Province (No. 2004ABC001)the Open Foundation of State Key Laboratory of Powder Metallurgy of Center South University (No. 200506123102A), China
文摘In order to improve parts accuracy, a method of adding heat balance support （HBS） was proposed, and the detailed algorithm for generating HBS was developed. A number of experiments and a comparison between similar softwares, showed that the algorithm is efficient and feasible. Moreover, different features of riBS were studied for different kinds of materials, such as PS and nylon. The research findings indicate that automatically adding HBS can significantly improve the accuracy of the parts, and that the algorithm for generating HBS is efficient and precise.
